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  • IList<T> and IReadOnlyList<T>

    - by Safak Gür
    My problem is that I have a method that can take a collection as parameter that, Has a Count property Has an integer indexer (get-only) And I don't know what type should this parameter be. I would choose IList<T> before .NET 4.5 since there is no other indexable collection interface for this and arrays implement it, which is a big plus. But .NET 4.5 introduces the new IReadOnlyList<T> interface and I want my method to support that, too. How can I write this method to support both IList<T> and IReadOnlyList<T> without violating the basic principles like DRY? Can I convert IList<T> to IReadOnlyList<T> somehow in an overload? What is the way to go here? Edit: Daniel's answer gave me some pretty ideas, I guess I'll go with this: public void Do<T>(IList<T> collection) { DoInternal(collection, collection.Count, i => collection[i]); } public void Do<T>(IReadOnlyList<T> collection) { DoInternal(collection, collection.Count, i => collection[i]); } private void DoInternal<T>(IEnumerable<T> collection, int count, Func<int, T> indexer) { // Stuff } Or I could just accept a ReadOnlyList<T> and provide an helper like this: public static class CollectionEx { public static IReadOnlyList<T> AsReadOnly<T>(this IList<T> collection) { if (collection == null) throw new ArgumentNullException("collection"); return new ReadOnlyWrapper<T>(collection); } private sealed class ReadOnlyWrapper<T> : IReadOnlyList<T> { private readonly IList<T> _Source; public int Count { get { return _Source.Count; } } public T this[int index] { get { return _Source[index]; } } public ReadOnlyWrapper(IList<T> source) { _Source = source; } public IEnumerator<T> GetEnumerator() { return _Source.GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); } } } Then I could call Do(array.AsReadOnly())

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  • What is the best approach in SQL to store multi-level descriptions?

    - by gime
    I need a new perspective on how to design a reliable and efficient SQL database to store multi-level arrays of data. This problem applies to many situations but I came up with this example: There are hundreds of products. Each product has an undefined number of parts. Each part is built from several elements. All products are described in the same way. All parts would require the same fields to describe them (let's say: price, weight, part name), all elements of all parts also have uniform design (for example: element code, manufacturer). Plain and simple. One element may be related to only part, and each part is related to one product only. I came up with idea of three tables: Products: -------------------------------------------- prod_id prod_name prod_price prod_desc 1 hoover 120 unused next Parts: ---------------------------------------------------- part_id part_name part_price part_weight prod_id 3 engine 10 20 1 and finally Elements: --------------------------------------- el_id el_code el_manufacturer part_id 1 BFG12 GE 3 Now, select a desired product, select all from PARTS where prod_id is the same, and then select all from ELEMENTS where part_id matches - after multiple queries you've got all data. I'm just not sure if this is the right approach. I've got also another idea, without ELEMENTS table. That would decrease queries but I'm a bit afraid it might be lame and bad practice. Instead of ELEMENTS table there are two more fields in the PARTS table, so it looks like this: part_id, part_name, part_price, part_weight, prod_id, part_el_code, part_el_manufacturer they would be text type, and for each part, information about elements would be stored as strings, this way: part_el_code | code_of_element1; code_of_element2; code_of_element3 part_el_manufacturer | manuf_of_element1; manuf_of_element2; manuf_of_element3 Then all we need is to explode() data from those fields, and we get arrays, easy to display. Of course this is not perfect and has some limitations, but is this idea ok? Or should I just go with the first idea? Or maybe there is a better approach to this problem? It's really hard to describe it in few words, and that means it's hard to search for answer. Also, understanding the principles of designing databases is not that easy as it seems.

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  • BNF – how to read syntax?

    - by Piotr Rodak
    A few days ago I read post of Jen McCown (blog) about her idea of blogging about random articles from Books Online. I think this is a great idea, even if Jen says that it’s not exciting or sexy. I noticed that many of the questions that appear on forums and other media arise from pure fact that people asking questions didn’t bother to read and understand the manual – Books Online. Jen came up with a brilliant, concise acronym that describes very well the category of posts about Books Online – RTFM365. I take liberty of tagging this post with the same acronym. I often come across questions of type – ‘Hey, i am trying to create a table, but I am getting an error’. The error often says that the syntax is invalid. 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT DEFAULT Guid_Default NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); 5 The answer is usually(1), ‘Ok, let me check it out.. Ah yes – you have to put name of the DEFAULT constraint before the type of constraint: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); Why many people stumble on syntax errors? Is the syntax poorly documented? No, the issue is, that correct syntax of the CREATE TABLE statement is documented very well in Books Online and is.. intimidating. Many people can be taken aback by the rather complex block of code that describes all intricacies of the statement. However, I don’t know better way of defining syntax of the statement or command. The notation that is used to describe syntax in Books Online is a form of Backus-Naur notatiion, called BNF for short sometimes. This is a notation that was invented around 50 years ago, and some say that even earlier, around 400 BC – would you believe? Originally it was used to define syntax of, rather ancient now, ALGOL programming language (in 1950’s, not in ancient India). If you look closer at the definition of the BNF, it turns out that the principles of this syntax are pretty simple. Here are a few bullet points: italic_text is a placeholder for your identifier <italic_text_in_angle_brackets> is a definition which is described further. [everything in square brackets] is optional {everything in curly brackets} is obligatory everything | separated | by | operator is an alternative ::= “assigns” definition to an identifier Yes, it looks like these six simple points give you the key to understand even the most complicated syntax definitions in Books Online. Books Online contain an article about syntax conventions – have you ever read it? Let’s have a look at fragment of the CREATE TABLE statement: 1 CREATE TABLE 2 [ database_name . [ schema_name ] . | schema_name . ] table_name 3 ( { <column_definition> | <computed_column_definition> 4 | <column_set_definition> } 5 [ <table_constraint> ] [ ,...n ] ) 6 [ ON { partition_scheme_name ( partition_column_name ) | filegroup 7 | "default" } ] 8 [ { TEXTIMAGE_ON { filegroup | "default" } ] 9 [ FILESTREAM_ON { partition_scheme_name | filegroup 10 | "default" } ] 11 [ WITH ( <table_option> [ ,...n ] ) ] 12 [ ; ] Let’s look at line 2 of the above snippet: This line uses rules 3 and 5 from the list. So you know that you can create table which has specified one of the following. just name – table will be created in default user schema schema name and table name – table will be created in specified schema database name, schema name and table name – table will be created in specified database, in specified schema database name, .., table name – table will be created in specified database, in default schema of the user. Note that this single line of the notation describes each of the naming schemes in deterministic way. The ‘optionality’ of the schema_name element is nested within database_name.. section. You can use either database_name and optional schema name, or just schema name – this is specified by the pipe character ‘|’. The error that user gets with execution of the first script fragment in this post is as follows: Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'DEFAULT'. Ok, let’s have a look how to find out the correct syntax. Line number 3 of the BNF fragment above contains reference to <column_definition>. Since column_definition is in angle brackets, we know that this is a reference to notion described further in the code. And indeed, the very next fragment of BNF contains syntax of the column definition. 1 <column_definition> ::= 2 column_name <data_type> 3 [ FILESTREAM ] 4 [ COLLATE collation_name ] 5 [ NULL | NOT NULL ] 6 [ 7 [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] 8 | [ IDENTITY [ ( seed ,increment ) ] [ NOT FOR REPLICATION ] 9 ] 10 [ ROWGUIDCOL ] [ <column_constraint> [ ...n ] ] 11 [ SPARSE ] Look at line 7 in the above fragment. It says, that the column can have a DEFAULT constraint which, if you want to name it, has to be prepended with [CONSTRAINT constraint_name] sequence. The name of the constraint is optional, but I strongly recommend you to make the effort of coming up with some meaningful name yourself. So the correct syntax of the CREATE TABLE statement from the beginning of the article is like this: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); That is practically everything you should know about BNF. I encourage you to study the syntax definitions for various statements and commands in Books Online, you can find really interesting things hidden there. Technorati Tags: SQL Server,t-sql,BNF,syntax   (1) No, my answer usually is a question – ‘What error message? What does it say?’. You’d be surprised to know how many people think I can go through time and space and look at their screen at the moment they received the error.

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  • A Guided Tour of Complexity

    - by JoshReuben
    I just re-read Complexity – A Guided Tour by Melanie Mitchell , protégé of Douglas Hofstadter ( author of “Gödel, Escher, Bach”) http://www.amazon.com/Complexity-Guided-Tour-Melanie-Mitchell/dp/0199798109/ref=sr_1_1?ie=UTF8&qid=1339744329&sr=8-1 here are some notes and links:   Evolved from Cybernetics, General Systems Theory, Synergetics some interesting transdisciplinary fields to investigate: Chaos Theory - http://en.wikipedia.org/wiki/Chaos_theory – small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for chaotic systems, rendering long-term prediction impossible. System Dynamics / Cybernetics - http://en.wikipedia.org/wiki/System_Dynamics – study of how feedback changes system behavior Network Theory - http://en.wikipedia.org/wiki/Network_theory – leverage Graph Theory to analyze symmetric  / asymmetric relations between discrete objects Algebraic Topology - http://en.wikipedia.org/wiki/Algebraic_topology – leverage abstract algebra to analyze topological spaces There are limits to deterministic systems & to computation. Chaos Theory definitely applies to training an ANN (artificial neural network) – different weights will emerge depending upon the random selection of the training set. In recursive Non-Linear systems http://en.wikipedia.org/wiki/Nonlinear_system – output is not directly inferable from input. E.g. a Logistic map: Xt+1 = R Xt(1-Xt) Different types of bifurcations, attractor states and oscillations may occur – e.g. a Lorenz Attractor http://en.wikipedia.org/wiki/Lorenz_system Feigenbaum Constants http://en.wikipedia.org/wiki/Feigenbaum_constants express ratios in a bifurcation diagram for a non-linear map – the convergent limit of R (the rate of period-doubling bifurcations) is 4.6692016 Maxwell’s Demon - http://en.wikipedia.org/wiki/Maxwell%27s_demon - the Second Law of Thermodynamics has only a statistical certainty – the universe (and thus information) tends towards entropy. While any computation can theoretically be done without expending energy, with finite memory, the act of erasing memory is permanent and increases entropy. Life & thought is a counter-example to the universe’s tendency towards entropy. Leo Szilard and later Claude Shannon came up with the Information Theory of Entropy - http://en.wikipedia.org/wiki/Entropy_(information_theory) whereby Shannon entropy quantifies the expected value of a message’s information in bits in order to determine channel capacity and leverage Coding Theory (compression analysis). Ludwig Boltzmann came up with Statistical Mechanics - http://en.wikipedia.org/wiki/Statistical_mechanics – whereby our Newtonian perception of continuous reality is a probabilistic and statistical aggregate of many discrete quantum microstates. This is relevant for Quantum Information Theory http://en.wikipedia.org/wiki/Quantum_information and the Physics of Information - http://en.wikipedia.org/wiki/Physical_information. Hilbert’s Problems http://en.wikipedia.org/wiki/Hilbert's_problems pondered whether mathematics is complete, consistent, and decidable (the Decision Problem – http://en.wikipedia.org/wiki/Entscheidungsproblem – is there always an algorithm that can determine whether a statement is true).  Godel’s Incompleteness Theorems http://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorems  proved that mathematics cannot be both complete and consistent (e.g. “This statement is not provable”). Turing through the use of Turing Machines (http://en.wikipedia.org/wiki/Turing_machine symbol processors that can prove mathematical statements) and Universal Turing Machines (http://en.wikipedia.org/wiki/Universal_Turing_machine Turing Machines that can emulate other any Turing Machine via accepting programs as well as data as input symbols) that computation is limited by demonstrating the Halting Problem http://en.wikipedia.org/wiki/Halting_problem (is is not possible to know when a program will complete – you cannot build an infinite loop detector). You may be used to thinking of 1 / 2 / 3 dimensional systems, but Fractal http://en.wikipedia.org/wiki/Fractal systems are defined by self-similarity & have non-integer Hausdorff Dimensions !!!  http://en.wikipedia.org/wiki/List_of_fractals_by_Hausdorff_dimension – the fractal dimension quantifies the number of copies of a self similar object at each level of detail – eg Koch Snowflake - http://en.wikipedia.org/wiki/Koch_snowflake Definitions of complexity: size, Shannon entropy, Algorithmic Information Content (http://en.wikipedia.org/wiki/Algorithmic_information_theory - size of shortest program that can generate a description of an object) Logical depth (amount of info processed), thermodynamic depth (resources required). Complexity is statistical and fractal. John Von Neumann’s other machine was the Self-Reproducing Automaton http://en.wikipedia.org/wiki/Self-replicating_machine  . Cellular Automata http://en.wikipedia.org/wiki/Cellular_automaton are alternative form of Universal Turing machine to traditional Von Neumann machines where grid cells are locally synchronized with their neighbors according to a rule. Conway’s Game of Life http://en.wikipedia.org/wiki/Conway's_Game_of_Life demonstrates various emergent constructs such as “Glider Guns” and “Spaceships”. Cellular Automatons are not practical because logical ops require a large number of cells – wasteful & inefficient. There are no compilers or general program languages available for Cellular Automatons (as far as I am aware). Random Boolean Networks http://en.wikipedia.org/wiki/Boolean_network are extensions of cellular automata where nodes are connected at random (not to spatial neighbors) and each node has its own rule –> they demonstrate the emergence of complex  & self organized behavior. Stephen Wolfram’s (creator of Mathematica, so give him the benefit of the doubt) New Kind of Science http://en.wikipedia.org/wiki/A_New_Kind_of_Science proposes the universe may be a discrete Finite State Automata http://en.wikipedia.org/wiki/Finite-state_machine whereby reality emerges from simple rules. I am 2/3 through this book. It is feasible that the universe is quantum discrete at the plank scale and that it computes itself – Digital Physics: http://en.wikipedia.org/wiki/Digital_physics – a simulated reality? Anyway, all behavior is supposedly derived from simple algorithmic rules & falls into 4 patterns: uniform , nested / cyclical, random (Rule 30 http://en.wikipedia.org/wiki/Rule_30) & mixed (Rule 110 - http://en.wikipedia.org/wiki/Rule_110 localized structures – it is this that is interesting). interaction between colliding propagating signal inputs is then information processing. Wolfram proposes the Principle of Computational Equivalence - http://mathworld.wolfram.com/PrincipleofComputationalEquivalence.html - all processes that are not obviously simple can be viewed as computations of equivalent sophistication. Meaning in information may emerge from analogy & conceptual slippages – see the CopyCat program: http://cognitrn.psych.indiana.edu/rgoldsto/courses/concepts/copycat.pdf Scale Free Networks http://en.wikipedia.org/wiki/Scale-free_network have a distribution governed by a Power Law (http://en.wikipedia.org/wiki/Power_law - much more common than Normal Distribution). They are characterized by hubs (resilience to random deletion of nodes), heterogeneity of degree values, self similarity, & small world structure. They grow via preferential attachment http://en.wikipedia.org/wiki/Preferential_attachment – tipping points triggered by positive feedback loops. 2 theories of cascading system failures in complex systems are Self-Organized Criticality http://en.wikipedia.org/wiki/Self-organized_criticality and Highly Optimized Tolerance http://en.wikipedia.org/wiki/Highly_optimized_tolerance. Computational Mechanics http://en.wikipedia.org/wiki/Computational_mechanics – use of computational methods to study phenomena governed by the principles of mechanics. This book is a great intuition pump, but does not cover the more mathematical subject of Computational Complexity Theory – http://en.wikipedia.org/wiki/Computational_complexity_theory I am currently reading this book on this subject: http://www.amazon.com/Computational-Complexity-Christos-H-Papadimitriou/dp/0201530821/ref=pd_sim_b_1   stay tuned for that review!

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  • 202 blog articles

    - by mprove
    All my blog articles under blogs.oracle.com since August 2005: 202 blog articles Apr 2012 blogs.oracle.com design patch Mar 2012 Interaction 12 - Critique Mar 2012 Typing. Clicking. Dancing. Feb 2012 Desktop Mobility in Hospitals with Oracle VDI /video Feb 2012 Interaction 12 in Dublin - Highlights of Day 3 Feb 2012 Interaction 12 in Dublin - Highlights of Day 2 Feb 2012 Interaction 12 in Dublin - Highlights of Day 1 Feb 2012 Shit Interaction Designers Say Feb 2012 Tips'n'Tricks for WebCenter #3: How to display custom page titles in Spaces Jan 2012 Tips'n'Tricks for WebCenter #2: How to create an Admin menu in Spaces and save a lot of time Jan 2012 Tips'n'Tricks for WebCenter #1: How to apply custom resources in Spaces Jan 2012 Merry XMas and a Happy 2012! Dec 2011 One Year Oracle SocialChat - The Movie Nov 2011 Frank Ludolph's Last Working Day Nov 2011 Hans Rosling at TED Oct 2011 200 Countries x 200 Years Oct 2011 Blog Aggregation for Desktop Virtualization Oct 2011 Oracle VDI at OOW 2011 Sep 2011 Design for Conversations & Conversations for Design Sep 2011 All Oracle UX Blogs Aug 2011 Farewell Loriot Aug 2011 Oracle VDI 3.3 Overview Aug 2011 Sutherland's Closing Remarks at HyperKult Aug 2011 Surface and Subface Aug 2011 Back to Childhood in UI Design Jul 2011 The Art of Engineering and The Engineering of Art Jul 2011 Oracle VDI Seminar - June-30 Jun 2011 SGD White Paper May 2011 TEDxHamburg Live Feed May 2011 Oracle VDI in 3 Minutes May 2011 Space Ship Earth 2011 May 2011 blog moving times Apr 2011 Frozen tag cloud Apr 2011 Oracle: Hardware Software Complete in 1953 Apr 2011 Interaction Design with Wireframes Apr 2011 A guide to closing down a project Feb 2011 Oracle VDI 3.2.2 Jan 2011 free VDI charts Jan 2011 Sun Founders Panel 2006 Dec 2010 Sutherland on Leadership Dec 2010 SocialChat: Efficiency of E20 Dec 2010 ALWAYS ON Desktop Virtualization Nov 2010 12,000 Desktops at JavaOne Nov 2010 SocialChat on Sharing Best Practices Oct 2010 Globe of Visitors Oct 2010 SocialChat about the Next Big Thing Oct 2010 Oracle VDI UX Story - Wireframes Oct 2010 What's a PC anyway? Oct 2010 SocialChat on Getting Things Done Oct 2010 SocialChat on Infoglut Oct 2010 IT Twenty Twenty Oct 2010 Desktop Virtualization Webcasts from OOW Oct 2010 Oracle VDI 3.2 Overview Sep 2010 Blog Usability Top 7 Sep 2010 100 and counting Aug 2010 Oracle'izing the VDI Blogs Aug 2010 SocialChat on Apple Aug 2010 SocialChat on Video Conferencing Aug 2010 Oracle VDI 3.2 - Features and Screenshots Aug 2010 SocialChat: Don't stop making waves Aug 2010 SocialChat: Giving Back to the Community Aug 2010 SocialChat on Learning in Meetings Aug 2010 iPAD's Natural User Interface Jul 2010 Last day for Sun Microsystems GmbH Jun 2010 SirValUse Celebration Snippets Jun 2010 10 years SirValUse - Happy Birthday! Jun 2010 Wim on Virtualization May 2010 New Home for Oracle VDI Apr 2010 Renaissance Slide Sorter Comments Apr 2010 Unboxing Sun Ray 3 Plus Apr 2010 Desktop Virtualisierung mit Sun VDI 3.1 Apr 2010 Blog Relaunch Mar 2010 Social Messaging Slides from CeBIT Mar 2010 Social Messaging Talk at CeBIT Feb 2010 Welcome Oracle Jan 2010 My last presentation at Sun Jan 2010 Ivan Sutherland on Leadership Jan 2010 Learning French with Sun VDI Jan 2010 Learning Danish with Sun Ray Jan 2010 VDI workshop in Nieuwegein Jan 2010 Happy New Year 2010 Jan 2010 On Creating Slides Dec 2009 Best VDI Ever Nov 2009 How to store the Big Bang Nov 2009 Social Enterprise Tools. Beipiel Sun. Nov 2009 Nov-19 Nov 2009 PDF and ODF links on your blog Nov 2009 Q&A on VDI and MySQL Cluster Nov 2009 Zürich next week: Swiss Intranet Summit 09 Nov 2009 Designing for a Sustainable World - World Usabiltiy Day, Nov-12 Nov 2009 How to export a desktop from VDI 3 Nov 2009 Virtualisation Roadshow in the UK Nov 2009 Project Wonderland at EDUCAUSE 09 Nov 2009 VDI Roadshow in Dublin, Nov-26, 2009 Nov 2009 Sun VDI at EDUCAUSE 09 Nov 2009 Sun VDI 3.1 Architecture and New Features Oct 2009 VDI 3.1 is Early-Access Sep 2009 Virtualization for MySQL on VMware Sep 2009 Silpion & 13. Stock Sommerparty Sep 2009 Sun Ray and VMware View 3.1.1 2009-08-31 New Set of Sun Ray Status Icons 2009-08-25 Virtualizing the VDI Core? 2009-08-23 World Usability Day Hamburg 2009 - CfP 2009-07-16 Rising Sun 2009-07-15 featuring twittermeme 2009-06-19 ISC09 Student Party on June-20 /Hamburg 2009-06-18 Before and behind the curtain of JavaOne 2009-06-09 20k desktops at JavaOne 2009-06-01 sweet microblogging 2009-05-25 VDI 3 - Why you need 3 VDI hosts and what you can do about that? 2009-05-21 IA Konferenz 2009 2009-05-20 Sun VDI 3 UX Story - Power of the Web 2009-05-06 Planet of Sun and Oracle User Experience Design 2009-04-22 Sun VDI 3 UX Story - User Research 2009-04-08 Sun VDI 3 UX Story - Concept Workshops 2009-04-06 Localized documentation for Sun Ray Connector for VMware View Manager 1.1 2009-04-03 Sun VDI 3 Press Release 2009-03-25 Sun VDI 3 launches today! 2009-03-25 Sun Ray Connector for VMware View Manager 1.1 Update 2009-03-11 desktop virtualization wiki relaunch 2009-03-06 VDI 3 at CeBIT hall 6, booth E36 2009-03-02 Keyboard layout problems with Sun Ray Connector for VMware VDM 2009-02-23 wikis.sun.com tips & tricks 2009-02-23 Sun VDI 3 is in Early Access 2009-02-09 VirtualCenter unable to decrypt passwords 2009-02-02 Sun & VMware Desktop Training 2009-01-30 VDI at next09? 2009-01-16 Sun VDI: How to use virtual machines with multiple network adapters 2009-01-07 Sun Ray and VMware View 2009-01-07 Hamburg World Usability Day 2008 - Webcasts 2009-01-06 Sun Ray Connector for VMware VDM slides 2008-12-15 mother of all demos 2008-12-08 Build your own Thumper 2008-12-03 Troubleshooting Sun Ray Connector for VMware VDM 2008-12-02 My Roller Tag Cloud 2008-11-28 Sun Ray Connector: SSL connection to VDM 2008-11-25 Setting up SSL and Sun Ray Connector for VMware VDM 2008-11-13 Inspiration for Today and Tomorrow 2008-10-23 Sun Ray Connector for VMware VDM released 2008-10-14 From Sketchpad to ILoveSketch 2008-10-09 Desktop Virtualization on Xing 2008-10-06 User Experience Forum on Xing 2008-10-06 Sun Ray Connector for VMware VDM certified 2008-09-17 Virtual Clouds over Las Vegas 2008-09-14 Bill Verplank sketches metaphors 2008-09-04 End of Early Access - Sun Ray Connector for VMware 2008-08-27 Early Access: Sun Ray Connector for VMware Virtual Desktop Manager 2008-08-12 Sun Virtual Desktop Connector - Insides on Recycling Part 2 2008-07-20 Sun Virtual Desktop Connector - Insides on Recycling Part 3 2008-07-20 Sun Virtual Desktop Connector - Insides on Recycling 2008-07-20 lost in wiki space 2008-07-07 Evolution of the Desktop 2008-06-17 Virtual Desktop Webcast 2008-06-16 Woodstock 2008-06-16 What's a Desktop PC anyway? 2008-06-09 Virtual-T-Box 2008-06-05 Virtualization Glossary 2008-05-06 Five User Experience Principles 2008-04-25 Virtualization News Feed 2008-04-21 Acetylcholinesterase - Second Season 2008-04-18 Acetylcholinesterase - End of Signal 2007-12-31 Produkt-Management ist... 2007-10-22 Usability Verbände, Verteiler und Netzwerke. 2007-10-02 The Meaning is the Message 2007-09-28 Visualization Methods 2007-09-10 Inhouse und Open Source Projekte – Usability verankern und Synergien nutzen 2007-09-03 Der Schwabe Darth Vader entdeckt das Virale Marketing 2007-08-29 Dick Hardt 3.0 on Identity 2.0 2007-08-27 quality of written text depends on the tool 2007-07-27 podcasts for reboot9 2007-06-04 It is the user's itch that need to be scratched 2007-05-25 A duel at reboot9 2007-05-14 Taxonomien und Folksonomien - Tagging als neues HCI-Element 2007-05-10 Dueling Interaction Models of Personal-Computing and Web-Computing 2007-03-01 22.März: Weizenbaum. Rebel at Work. /Filmpremiere Hamburg 2007-02-25 Bruce Sterling at UbiComp 2006 /webcast 2006-11-12 FSOSS 2006 /webcasts 2006-11-10 Highway 101 2006-11-09 User Experience Roundtable Hamburg: EuroGEL 2006 2006-11-08 Douglas Adams' Hyperland (BBC 1990) 2006-10-08 Taxonomien und Folksonomien – Tagging als neues HCI-Element 2006-09-13 Usability im Unternehmen 2006-09-13 Doug does HyperScope 2006-08-26 TED Talks and TechTalks 2006-08-21 Kai Krause über seine Freundschaft zu Douglas Adams 2006-07-20 Rebel At Work: Film Portrait on Weizenbaum 2006-07-04 Gabriele Fischer, mp3 2006-06-07 Dick Hardt at ETech 06 2006-06-05 Weinberger: From Control to Conversation 2006-04-16 Eye Tracking at User Experience Roundtable Hamburg 2006-04-14 dropping knowledge 2006-04-09 GEL 2005 2006-03-13 slide photos of reboot7 2006-03-04 Dick Hardt on Identity 2.0 2006-02-28 User Experience Newsletter #13: Versioning 2006-02-03 Ester Dyson on Choice and Happyness 2006-02-02 Requirements-Engineering im Spannungsfeld von Individual- und Produktsoftware 2006-01-15 User Experience Newsletter #12: Intuition Quiz 2005-11-30 User Experience und Requirements-Engineering für Software-Projekte 2005-10-31 Ivan Sutherland on "Research and Fun" 2005-10-18 Ars Electronica / Mensch und Computer 2005 2005-09-14 60 Jahre nach Memex: Über die Unvereinbarkeit von Desktop- und Web-Paradigma 2005-08-31 reboot 7 2005-06-30

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  • Migrating SQL Server Databases – The DBA’s Checklist (Part 1)

    - by Sadequl Hussain
    It is a fact of life: SQL Server databases change homes. They move from one instance to another, from one version to the next, from old servers to new ones.  They move around as an organisation’s data grows, applications are enhanced or new versions of the database software are released. If not anything else, servers become old and unreliable and databases eventually need to find a new home. Consider the following scenarios: 1.     A new  database application is rolled out in a production server from the development or test environment 2.     A copy of the production database needs to be installed in a test server for troubleshooting purposes 3.     A copy of the development database is regularly refreshed in a test server during the system development life cycle 4.     A SQL Server is upgraded to a newer version. This can be an in-place upgrade or a side-by-side migration 5.     One or more databases need to be moved between different instances as part of a consolidation strategy. The instances can be running the same or different version of SQL Server 6.     A database has to be restored from a backup file provided by a third party application vendor 7.     A backup of the database is restored in the same or different instance for disaster recovery 8.     A database needs to be migrated within the same instance: a.     Files are moved from direct attached storage to storage area network b.    The same database is copied under a different name for another application Migrating SQL Server database applications is a complex topic in itself. There are a number of components that can be involved: jobs, DTS or SSIS packages, logins or linked servers are only few pieces of the puzzle. However, in this article we will focus only on the central part of migration: the installation of the database itself. Unless it is an in-place upgrade, typically the database is taken from a source server and installed in a destination instance.  Most of the time, a full backup file is used for the rollout. The backup file is either provided to the DBA or the DBA takes the backup and restores it in the target server. Sometimes the database is detached from the source and the files are copied to and attached in the destination. Regardless of the method of copying, moving, refreshing, restoring or upgrading the physical database, there are a number of steps the DBA should follow before and after it has been installed in the destination. It is these post database installation steps we are going to discuss below. Some of these steps apply in almost every scenario described above while some will depend on the type of objects contained within the database.  Also, the principles hold regardless of the number of databases involved. Step 1:  Make a copy of data and log files when attaching and detaching When detaching and attaching databases, ensure you have made copies of the data and log files if the destination is running a newer version of SQL Server. This is because once attached to a newer version, the database cannot be detached and attached back to an older version. Trying to do so will give you a message like the following: Server: Msg 602, Level 21, State 50, Line 1 Could not find row in sysindexes for database ID 6, object ID 1, index ID 1. Run DBCC CHECKTABLE on sysindexes. Connection Broken If you try to backup the attached database and restore it in the source, it will still fail. Similarly, if you are restoring the database in a newer version, it cannot be backed up or detached and put back in an older version of SQL. Unlike detach and attach method though, you do not lose the backup file or the original database here. When detaching and attaching a database, it is important you keep all the log files available along with the data files. It is possible to attach a database without a log file and SQL Server can be instructed to create a new log file, however this does not work if the database was detached when the primary file group was read-only. You will need all the log files in such cases. Step 2: Change database compatibility level Once the database has been restored or attached to a newer version of SQL Server, change the database compatibility level to reflect the newer version unless there is a compelling reason not to do so. When attaching or restoring from a previous version of SQL, the database retains the older version’s compatibility level.  The only time you would want to keep a database with an older compatibility level is when the code within your database is no longer supported by SQL Server. For example, outer joins with *= or the =* operators were still possible in SQL 2000 (with a warning message), but not in SQL 2005 anymore. If your stored procedures or triggers are using this form of join, you would want to keep the database with an older compatibility level.  For a list of compatibility issues between older and newer versions of SQL Server databases, refer to the Books Online under the sp_dbcmptlevel topic. Application developers and architects can help you in deciding whether you should change the compatibility level or not. You can always change the compatibility mode from the newest to an older version if necessary. To change the compatibility level, you can either use the database’s property from the SQL Server Management Studio or use the sp_dbcmptlevel stored procedure.   Bear in mind that you cannot run the built-in reports for databases from SQL Server Management Studio if you keep the database with an older compatibility level. The following figure shows the error message I received when trying to run the “Disk Usage by Top Tables” report against a database. This database was hosted in a SQL Server 2005 system and still had a compatibility mode 80 (SQL 2000).     Continues…

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  • Best of Breed vs. Suite – Oracle’s SaaS Delivers Both

    - by yaldahhakim
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} The debate of which is better: “best of breed” business applications vs. an integrated suite is certainly not a new conversation. This has been argued between IT vendors and CIOs for years. It’s also important to clarify that “best of breed” does not necessarily translate into being the richest functionality; rather it’s often about just having the best fit solution to solve a specific business problem or need. So what does cloud have to do with the niche vs. suite debate? Consuming business applications in a cloud or SaaS deployment model can change the best of breed vs. suite discussion - if the cloud is done right. It’s having your cake and eating it too only better: you don’t have to gather all the ingredients or wait to bake your cake, and you can adjust how big of slice you take. Before you eat, it’s worth pausing to recall much of what we learned about IT over the last decade. These basic IT principles still hold true even though the financial model has changed from buying to renting. In other words, what’s under the technology hood still matters. Architecture and development methodologies like building an application based on open standards so it works with other systems - is still important. Data and information silos, complex integrations, and proprietary technologies that lock you in, are still bad. While some may argue that IT no longer matters with cloud, the opposite is actually true. If anything cloud can help return IT back to its rightful place as key strategic asset vs. a liability on the balance sheet. The “I” in CIO was never meant to stand for “integration” yet it’s amazing how much time and money is poured into these types of initiatives for most organizations each year. Rather the “I” needs to stand for “innovation”. This is where Oracle SaaS can uniquely help. Oracle’s application strategy has not really changed over the years. It’s always been about bringing the best and richest functionality across the enterprise to our customers while leveraging a common, standards-based, and enterprise-grade platform. So not jut best fit, but the best capabilities based on the input of thousands of enterprise customers across the globe. Oracle invests billions in R&D every year to add new capabilities to the broadest cloud portfolio in the industry, spanning across functional pillars like CRM, HCM, ERP, etc. And where it makes sense, Oracle combines key strategic acquisitions to complement organic functionality. The result is best of breed delivered in a suite. Again this is not something new. The game changer now with cloud is that it impacts HOW Oracle customers adopt the richest, most modern applications across the business – and continue on getting it. Consuming oracle applications in the cloud means you can adopt new capabilities and updates very quickly and easily. There’s no hardware to buy or software to manage. Oracle does it for you. Low upfront costs and an OpEx financial model is the easy part. Oracle Cloud Applications take it a big step further. For organizations that demand having the latest and richest functionality and accelerating the time to value from their IT investment, Oracle Cloud is the right path. It’s about holistically changing the “hows” and the “whys” of the organization by leveraging transformational innovations like social, mobile, and big data in a consistent and more powerful way. Not just about sales force automation or talent management. These technologies should impact all parts of the company and Oracle Cloud is the enterprise-grade delivery vehicle. Oracle SaaS helps break down barriers of adoption and is eases the headache of upgrades, investing in new supporting hardware, or adding internal expertise to manage it all. With Oracle Cloud, customers can get best of breed capabilities in either a full suite model or a la carte. And because it’s entirely built on open standards, it’s built to co-exist with existing IT investments. Updates can be automatic or delayed based on a customer’s requirements. And it’s complete – a full suite of cross pillar functionality. Even better, if you don’t like it, need more or less, just turn the dial up or down. Just like your utility bill, you pay for what you use, and can consume more or less power whenever you need it. Lower cost, lower investment risk, without compromising on functionality, security, or performance. Technology still matters in the cloud. So our cloud customers also like that when they adopt our cloud applications, they also get the best underlying technology, from the middleware and database platform down to infrastructure and Oracle’s engineered systems. Therefore it’s not just the greatest and latest in application functionality, but everything underneath that makes it work is also the latest and greatest. The best of breed technology stack powering best of breed business applications, and all delivered in a subscription based model. The best of both worlds. Yep, that’s the idea.

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  • Time Tracking on an Agile Team

    - by Stephen.Walther
    What’s the best way to handle time-tracking on an Agile team? Your gut reaction to this question might be to resist any type of time-tracking at all. After all, one of the principles of the Agile Manifesto is “Individuals and interactions over processes and tools”.  Forcing the developers on your team to track the amount of time that they devote to completing stories or tasks might seem like useless bureaucratic red tape: an impediment to getting real work done. I completely understand this reaction. I’ve been required to use time-tracking software in the past to account for each hour of my workday. It made me feel like Fred Flintstone punching in at the quarry mine and not like a professional. Why You Really Do Need Time-Tracking There are, however, legitimate reasons to track time spent on stories even when you are a member of an Agile team.  First, if you are working with an outside client, you might need to track the number of hours spent on different stories for the purposes of billing. There might be no way to avoid time-tracking if you want to get paid. Second, the Product Owner needs to know when the work on a story has gone over the original time estimated for the story. The Product Owner is concerned with Return On Investment. If the team has gone massively overtime on a story, then the Product Owner has a legitimate reason to halt work on the story and reconsider the story’s business value. Finally, you might want to track how much time your team spends on different types of stories or tasks. For example, if your team is spending 75% of their time doing testing then you might need to bring in more testers. Or, if 10% of your team’s time is expended performing a software build at the end of each iteration then it is time to consider better ways of automating the build process. Time-Tracking in SonicAgile For these reasons, we added time-tracking as a feature to SonicAgile which is our free Agile Project Management tool. We were heavily influenced by Jeff Sutherland (one of the founders of Scrum) in the way that we implemented time-tracking (see his article http://scrum.jeffsutherland.com/2007/03/time-tracking-is-anti-scrum-what-do-you.html). In SonicAgile, time-tracking is disabled by default. If you want to use this feature then the project owner must enable time-tracking in Project Settings. You can choose to estimate using either days or hours. If you are estimating at the level of stories then it makes more sense to choose days. Otherwise, if you are estimating at the level of tasks then it makes more sense to use hours. After you enable time-tracking then you can assign three estimates to a story: Original Estimate – This is the estimate that you enter when you first create a story. You don’t change this estimate. Time Spent – This is the amount of time that you have already devoted to the story. You update the time spent on each story during your daily standup meeting. Time Left – This is the amount of time remaining to complete the story. Again, you update the time left during your daily standup meeting. So when you first create a story, you enter an original estimate that becomes the time left. During each daily standup meeting, you update the time spent and time left for each story on the Kanban. If you had perfect predicative power, then the original estimate would always be the same as the sum of the time spent and the time left. For example, if you predict that a story will take 5 days to complete then on day 3, the story should have 3 days spent and 2 days left. Unfortunately, never in the history of mankind has anyone accurately predicted the exact amount of time that it takes to complete a story. For this reason, SonicAgile does not update the time spent and time left automatically. Each day, during the daily standup, your team should update the time spent and time left for each story. For example, the following table shows the history of the time estimates for a story that was originally estimated to take 3 days but, eventually, takes 5 days to complete: Day Original Estimate Time Spent Time Left Day 1 3 days 0 days 3 days Day 2 3 days 1 day 2 days Day 3 3 days 2 days 2 days Day 4 3 days 3 days 2 days Day 5 3 days 4 days 0 days In the table above, everything goes as predicted until you reach day 3. On day 3, the team realizes that the work will require an additional two days. The situation does not improve on day 4. All of the sudden, on day 5, all of the remaining work gets done. Real work often follows this pattern. There are long periods when nothing gets done punctuated by occasional and unpredictable bursts of progress. We designed SonicAgile to make it as easy as possible to track the time spent and time left on a story. Detecting when a Story Goes Over the Original Estimate Sometimes, stories take much longer than originally estimated. There’s a surprise. For example, you discover that a new software component is incompatible with existing software components. Or, you discover that you have to go through a month-long certification process to finish a story. In those cases, the Product Owner has a legitimate reason to halt work on a story and re-evaluate the business value of the story. For example, the Product Owner discovers that a story will require weeks to implement instead of days, then the story might not be worth the expense. SonicAgile displays a warning on both the Backlog and the Kanban when the time spent on a story goes over the original estimate. An icon of a clock is displayed. Time-Tracking and Tasks Another optional feature of SonicAgile is tasks. If you enable Tasks in Project Settings then you can break stories into one or more tasks. You can perform time-tracking at the level of a story or at the level of a task. If you don’t break a story into tasks then you can enter the time left and time spent for the story. As soon as you break a story into tasks, then you can no longer enter the time left and time spent at the level of the story. Instead, the time left and time spent for a story is rolled up from its tasks. On the Kanban, you can see how the time left and time spent for each task gets rolled up into each story. The progress bar for the story is rolled up from the progress bars for each task. The original estimate is never rolled up – even when you break a story into tasks. A story’s original estimate is entered separately from the original estimates of each of the story’s tasks. Summary Not every Agile team can avoid time-tracking. You might be forced to track time to get paid, to detect when you are spending too much time on a particular story, or to track the amount of time that you are devoting to different types of tasks. We designed time-tracking in SonicAgile to require the least amount of work to track the information that you need. Time-tracking is an optional feature. If you enable time-tracking then you can track the original estimate, time left, and time spent for each story and task. You can use time-tracking with SonicAgile for free. Register at http://SonicAgile.com.

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  • Replication Services as ETL extraction tool

    - by jorg
    In my last blog post I explained the principles of Replication Services and the possibilities it offers in a BI environment. One of the possibilities I described was the use of snapshot replication as an ETL extraction tool: “Snapshot Replication can also be useful in BI environments, if you don’t need a near real-time copy of the database, you can choose to use this form of replication. Next to an alternative for Transactional Replication it can be used to stage data so it can be transformed and moved into the data warehousing environment afterwards. In many solutions I have seen developers create multiple SSIS packages that simply copies data from one or more source systems to a staging database that figures as source for the ETL process. The creation of these packages takes a lot of (boring) time, while Replication Services can do the same in minutes. It is possible to filter out columns and/or records and it can even apply schema changes automatically so I think it offers enough features here. I don’t know how the performance will be and if it really works as good for this purpose as I expect, but I want to try this out soon!” Well I have tried it out and I must say it worked well. I was able to let replication services do work in a fraction of the time it would cost me to do the same in SSIS. What I did was the following: Configure snapshot replication for some Adventure Works tables, this was quite simple and straightforward. Create an SSIS package that executes the snapshot replication on demand and waits for its completion. This is something that you can’t do with out of the box functionality. While configuring the snapshot replication two SQL Agent Jobs are created, one for the creation of the snapshot and one for the distribution of the snapshot. Unfortunately these jobs are  asynchronous which means that if you execute them they immediately report back if the job started successfully or not, they do not wait for completion and report its result afterwards. So I had to create an SSIS package that executes the jobs and waits for their completion before the rest of the ETL process continues. Fortunately I was able to create the SSIS package with the desired functionality. I have made a step-by-step guide that will help you configure the snapshot replication and I have uploaded the SSIS package you need to execute it. Configure snapshot replication   The first step is to create a publication on the database you want to replicate. Connect to SQL Server Management Studio and right-click Replication, choose for New.. Publication…   The New Publication Wizard appears, click Next Choose your “source” database and click Next Choose Snapshot publication and click Next   You can now select tables and other objects that you want to publish Expand Tables and select the tables that are needed in your ETL process In the next screen you can add filters on the selected tables which can be very useful. Think about selecting only the last x days of data for example. Its possible to filter out rows and/or columns. In this example I did not apply any filters. Schedule the Snapshot Agent to run at a desired time, by doing this a SQL Agent Job is created which we need to execute from a SSIS package later on. Next you need to set the Security Settings for the Snapshot Agent. Click on the Security Settings button.   In this example I ran the Agent under the SQL Server Agent service account. This is not recommended as a security best practice. Fortunately there is an excellent article on TechNet which tells you exactly how to set up the security for replication services. Read it here and make sure you follow the guidelines!   On the next screen choose to create the publication at the end of the wizard Give the publication a name (SnapshotTest) and complete the wizard   The publication is created and the articles (tables in this case) are added Now the publication is created successfully its time to create a new subscription for this publication.   Expand the Replication folder in SSMS and right click Local Subscriptions, choose New Subscriptions   The New Subscription Wizard appears   Select the publisher on which you just created your publication and select the database and publication (SnapshotTest)   You can now choose where the Distribution Agent should run. If it runs at the distributor (push subscriptions) it causes extra processing overhead. If you use a separate server for your ETL process and databases choose to run each agent at its subscriber (pull subscriptions) to reduce the processing overhead at the distributor. Of course we need a database for the subscription and fortunately the Wizard can create it for you. Choose for New database   Give the database the desired name, set the desired options and click OK You can now add multiple SQL Server Subscribers which is not necessary in this case but can be very useful.   You now need to set the security settings for the Distribution Agent. Click on the …. button Again, in this example I ran the Agent under the SQL Server Agent service account. Read the security best practices here   Click Next   Make sure you create a synchronization job schedule again. This job is also necessary in the SSIS package later on. Initialize the subscription at first synchronization Select the first box to create the subscription when finishing this wizard Complete the wizard by clicking Finish The subscription will be created In SSMS you see a new database is created, the subscriber. There are no tables or other objects in the database available yet because the replication jobs did not ran yet. Now expand the SQL Server Agent, go to Jobs and search for the job that creates the snapshot:   Rename this job to “CreateSnapshot” Now search for the job that distributes the snapshot:   Rename this job to “DistributeSnapshot” Create an SSIS package that executes the snapshot replication We now need an SSIS package that will take care of the execution of both jobs. The CreateSnapshot job needs to execute and finish before the DistributeSnapshot job runs. After the DistributeSnapshot job has started the package needs to wait until its finished before the package execution finishes. The Execute SQL Server Agent Job Task is designed to execute SQL Agent Jobs from SSIS. Unfortunately this SSIS task only executes the job and reports back if the job started succesfully or not, it does not report if the job actually completed with success or failure. This is because these jobs are asynchronous. The SSIS package I’ve created does the following: It runs the CreateSnapshot job It checks every 5 seconds if the job is completed with a for loop When the CreateSnapshot job is completed it starts the DistributeSnapshot job And again it waits until the snapshot is delivered before the package will finish successfully Quite simple and the package is ready to use as standalone extract mechanism. After executing the package the replicated tables are added to the subscriber database and are filled with data:   Download the SSIS package here (SSIS 2008) Conclusion In this example I only replicated 5 tables, I could create a SSIS package that does the same in approximately the same amount of time. But if I replicated all the 70+ AdventureWorks tables I would save a lot of time and boring work! With replication services you also benefit from the feature that schema changes are applied automatically which means your entire extract phase wont break. Because a snapshot is created using the bcp utility (bulk copy) it’s also quite fast, so the performance will be quite good. Disadvantages of using snapshot replication as extraction tool is the limitation on source systems. You can only choose SQL Server or Oracle databases to act as a publisher. So if you plan to build an extract phase for your ETL process that will invoke a lot of tables think about replication services, it would save you a lot of time and thanks to the Extract SSIS package I’ve created you can perfectly fit it in your usual SSIS ETL process.

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  • Portal And Content - Content Integration - Best Practices

    - by Stefan Krantz
    Lately we have seen an increase in projects that have failed to either get user friendly content integration or non satisfactory performance. Our intention is to mitigate any knowledge gap that our previous post might have left you with, therefore this post will repeat some recommendation or reference back to old useful post. Moreover this post will help you understand ground up how to design, architect and implement business enabled, responsive and performing portals with complex requirements on business centric information publishing. Design the Information Model The key to successful portal deployments is Information modeling, it's a key task to understand the use case you designing for, therefore I have designed a set of question you need to ask yourself or your customer: Question: Who will own the content, IT or Business? Answer: BusinessQuestion: Who will publish the content, IT or Business? Answer: BusinessQuestion: Will there be multiple publishers? Answer: YesQuestion: Are the publishers computer scientist?Answer: NoQuestion: How often do the information changes, daily, weekly, monthly?Answer: Daily, weekly If your answers to the questions matches at least 2, we strongly recommend you design your content with following principles: Divide your pages in to logical sections, where each section is marked with its purpose Assign capabilities to each section, does it contain text, images, formatting and/or is it static and is populated through other contextual information Select editor/design element type WYSIWYG - Rich Text Plain Text - non-format text Image - Image object Static List - static list of formatted informationDynamic Data List - assembled information from multiple data files through CMIS query The result of such design map could look like following below examples: Based on the outcome of the required elements in the design column 3 from the left you will now simply design a data model in WebCenter Content - Site Studio by creating a Region Definition structure matching your design requirements.For more information on how to create a Region definition see following post: Region Definition Post - note see instruction 7 for details. Each region definition can now be used to instantiate data files, a data file will hold the actual data for each element in the region definition. Another way you can see this is to compare the region definition as an extension to the metadata model in WebCenter Content for each data file item. Design content templates With a solid dependable information model we can now proceed to template creation and page design, in this phase focuses on how to place the content sections from the region definition on the page via a Content Presenter template. Remember by creating content presenter templates you will leverage the latest and most integrated technology WebCenter has to offer. This phase is much easier since the you already have the information model and design wire-frames to base the logic on, however there is still few considerations to pay attention to: Base the template on ADF and make only necessary exceptions to markup when required Leverage ADF design components for Tabs, Accordions and other similar components, this way the design in the content published areas will comply with other design areas based on custom ADF taskflows There is no performance impact when using meta data or region definition based data All data access regardless of type, metadata or xml data it can be accessed via the Content Presenter - Node. See below for applied examples on how to access data Access metadata property from Document - #{node.propertyMap['myProp'].value}myProp in this example can be for instance (dDocName, dDocTitle, xComments or any other available metadata) Access element data from data file xml - #{node.propertyMap['[Region Definition Name]:[Element name]'].asTextHtml}Region Definition Name is the expect region definition that the current data file is instantiatingElement name is the element value you like to grab from the data file I recommend you read following  useful post on content template topic:CMIS queries and template creation - note see instruction 9 for detailsStatic List template rendering For more information on templates:Single Item Content TemplateMulti Item Content TemplateExpression Language Internationalization Considerations When integrating content assets via content presenter you by now probably understand that the content item/data file is wired to the page, what is also pretty common at this stage is that the content item/data file only support one language since its not practical or business friendly to mix that into a complex structure. Therefore you will be left with a very common dilemma that you will have to either build a complete new portal for each locale, which is not an good option! However with little bit of information modeling and clear naming convention this can be addressed. Basically you can simply make sure that all content item/data file are named with a predictable naming convention like "Content1_EN" for the English rendition and "Content1_ES" for the Spanish rendition. This way through simple none complex customizations you will be able to dynamically switch the actual content item/data file just before rendering. By following proposed approach above you not only enable a simple mechanism for internationalized content you also preserve the functionality in the content presenter to support business accessible run-time publishing of information on existing and new pages. I recommend you read following useful post on Internationalization topics:Internationalize with Content Presenter Integrate with Review & Approval processes Today the Review and approval functionality and configuration is based out of WebCenter Content - Criteria Workflows. Criteria Workflows uses the metadata of the checked in document to evaluate if the document is under any review/approval process. So for instance if a Criteria Workflow is configured to force any documents with Version = "2" or "higher" and Content Type is "Instructions", any matching content item version on check in will now enter the workflow before getting released for general access. Few things to consider when configuring Criteria Workflows: Make sure to not trigger on version one for Content Items that are Data Files - if you trigger on version 1 you will not only approve an empty document you will also have a content presenter pointing to a none existing document - since the document will only be available after successful completion of the workflow Approval workflows sometimes requires more complex criteria, the recommendation if that is the case is that the meta data triggering such criteria is automatically populated, this can be achieved through many approaches including Content Profiles Criteria workflows are configured and managed in WebCenter Content Administration Applets where you can configure one or more workflows. When you configured Criteria workflows the Content Presenter will support the editors with the approval process directly inline in the "Contribution mode" of the portal. In addition to approve/reject and details of the task, the content presenter natively support the user to view the current and future version of the change he/she is approving. See below for example: Architectural recommendation To support review&approval processes - minimize the amount of data files per page Each CMIS query can consume significant time depending on the complexity of the query - minimize the amount of CMIS queries per page Use Content Presenter Templates based on ADF - this way you minimize the design considerations and optimize the usage of caching Implement the page in as few Data files as possible - simplifies publishing process, increases performance and simplifies release process Named data file (node) or list of named nodes when integrating to pages increases performance vs. querying for data Named data file (node) or list of named nodes when integrating to pages enables business centric page creation and publishing and reduces the need for IT department interaction Summary Just because one architectural decision solves a business problem it doesn't mean its the right one, when designing portals all architecture has to be in harmony and not impacting each other. For instance the most technical complex solution is not always the best since it will most likely defeat the business accessibility, performance or both, therefore the best approach is to first design for simplicity that even a non-technical user can operate, after that consider the performance impact and final look at the technology challenges these brings and workaround them first with out-of-the-box features, after that design and develop functions to complement the short comings.

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  • European Interoperability Framework - a new beginning?

    - by trond-arne.undheim
    The most controversial document in the history of the European Commission's IT policy is out. EIF is here, wrapped in the Communication "Towards interoperability for European public services", and including the new feature European Interoperability Strategy (EIS), arguably a higher strategic take on the same topic. Leaving EIS aside for a moment, the EIF controversy has been around IPR, defining open standards and about the proper terminology around standardization deliverables. Today, as the document finally emerges, what is the verdict? First of all, to be fair to those among you who do not spend your lives in the intricate labyrinths of Commission IT policy documents on interoperability, let's define what we are talking about. According to the Communication: "An interoperability framework is an agreed approach to interoperability for organisations that want to collaborate to provide joint delivery of public services. Within its scope of applicability, it specifies common elements such as vocabulary, concepts, principles, policies, guidelines, recommendations, standards, specifications and practices." The Good - EIF reconfirms that "The Digital Agenda can only take off if interoperability based on standards and open platforms is ensured" and also confirms that "The positive effect of open specifications is also demonstrated by the Internet ecosystem." - EIF takes a productive and pragmatic stance on openness: "In the context of the EIF, openness is the willingness of persons, organisations or other members of a community of interest to share knowledge and stimulate debate within that community, the ultimate goal being to advance knowledge and the use of this knowledge to solve problems" (p.11). "If the openness principle is applied in full: - All stakeholders have the same possibility of contributing to the development of the specification and public review is part of the decision-making process; - The specification is available for everybody to study; - Intellectual property rights related to the specification are licensed on FRAND terms or on a royalty-free basis in a way that allows implementation in both proprietary and open source software" (p. 26). - EIF is a formal Commission document. The former EIF 1.0 was a semi-formal deliverable from the PEGSCO, a working group of Member State representatives. - EIF tackles interoperability head-on and takes a clear stance: "Recommendation 22. When establishing European public services, public administrations should prefer open specifications, taking due account of the coverage of functional needs, maturity and market support." - The Commission will continue to support the National Interoperability Framework Observatory (NIFO), reconfirming the importance of coordinating such approaches across borders. - The Commission will align its internal interoperability strategy with the EIS through the eCommission initiative. - One cannot stress the importance of using open standards enough, whether in the context of open source or non-open source software. The EIF seems to have picked up on this fact: What does the EIF says about the relation between open specifications and open source software? The EIF introduces, as one of the characteristics of an open specification, the requirement that IPRs related to the specification have to be licensed on FRAND terms or on a royalty-free basis in a way that allows implementation in both proprietary and open source software. In this way, companies working under various business models can compete on an equal footing when providing solutions to public administrations while administrations that implement the standard in their own software (software that they own) can share such software with others under an open source licence if they so decide. - EIF is now among the center pieces of the Digital Agenda (even though this demands extensive inter-agency coordination in the Commission): "The EIS and the EIF will be maintained under the ISA Programme and kept in line with the results of other relevant Digital Agenda actions on interoperability and standards such as the ones on the reform of rules on implementation of ICT standards in Europe to allow use of certain ICT fora and consortia standards, on issuing guidelines on essential intellectual property rights and licensing conditions in standard-setting, including for ex-ante disclosure, and on providing guidance on the link between ICT standardisation and public procurement to help public authorities to use standards to promote efficiency and reduce lock-in.(Communication, p.7)" All in all, quite a few good things have happened to the document in the two years it has been on the shelf or was being re-written, depending on your perspective, in any case, awaiting the storms to calm. The Bad - While a certain pragmatism is required, and governments cannot migrate to full openness overnight, EIF gives a bit too much room for governments not to apply the openness principle in full. Plenty of reasons are given, which should maybe have been put as challenges to be overcome: "However, public administrations may decide to use less open specifications, if open specifications do not exist or do not meet functional interoperability needs. In all cases, specifications should be mature and sufficiently supported by the market, except if used in the context of creating innovative solutions". - EIF does not use the internationally established terminology: open standards. Rather, the EIF introduces the notion of "formalised specification". How do "formalised specifications" relate to "standards"? According to the FAQ provided: The word "standard" has a specific meaning in Europe as defined by Directive 98/34/EC. Only technical specifications approved by a recognised standardisation body can be called a standard. Many ICT systems rely on the use of specifications developed by other organisations such as a forum or consortium. The EIF introduces the notion of "formalised specification", which is either a standard pursuant to Directive 98/34/EC or a specification established by ICT fora and consortia. The term "open specification" used in the EIF, on the one hand, avoids terminological confusion with the Directive and, on the other, states the main features that comply with the basic principle of openness laid down in the EIF for European Public Services. Well, this may be somewhat true, but in reality, Europe is 30 year behind in terminology. Unless the European Standardization Reform gets completed in the next few months, most Member States will likely conclude that they will go on referencing and using standards beyond those created by the three European endorsed monopolists of standardization, CEN, CENELEC and ETSI. Who can afford to begin following the strict Brussels rules for what they can call open standards when, in reality, standards stemming from global standardization organizations, so-called fora/consortia, dominate in the IT industry. What exactly is EIF saying? Does it encourage Member States to go on using non-ESO standards as long as they call it something else? I guess I am all for it, although it is a bit cumbersome, no? Why was there so much interest around the EIF? The FAQ attempts to explain: Some Member States have begun to adopt policies to achieve interoperability for their public services. These actions have had a significant impact on the ecosystem built around the provision of such services, e.g. providers of ICT goods and services, standardisation bodies, industry fora and consortia, etc... The Commission identified a clear need for action at European level to ensure that actions by individual Member States would not create new electronic barriers that would hinder the development of interoperable European public services. As a result, all stakeholders involved in the delivery of electronic public services in Europe have expressed their opinions on how to increase interoperability for public services provided by the different public administrations in Europe. Well, it does not take two years to read 50 consultation documents, and the EU Standardization Reform is not yet completed, so, more pragmatically, you finally had to release the document. Ok, let's leave some of that aside because the document is out and some people are happy (and others definitely not). The Verdict Considering the controversy, the delays, the lobbying, and the interests at stake both in the EU, in Member States and among vendors large and small, this document is pretty impressive. As with a good wine that has not yet come to full maturity, let's say that it seems to be coming in in the 85-88/100 range, but only a more fine-grained analysis, enjoyment in good company, and ultimately, implementation, will tell. The European Commission has today adopted a significant interoperability initiative to encourage public administrations across the EU to maximise the social and economic potential of information and communication technologies. Today, we should rally around this achievement. Tomorrow, let's sit down and figure out what it means for the future.

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  • top tweets WebLogic Partner Community – June 2013

    - by JuergenKress
    Send us your tweets @wlscommunity #WebLogicCommunity and follow us on twitter http://twitter.com/wlscommunity. Please feel free to send us your news! Lucas Jellema ?Getting started with Java EE 7: The Tutorial http://docs.oracle.com/javaee/7/tutorial/doc/home.htm … Simon Haslam I'm looking forward to starting a "WLS on ODA" proof of concept - some ideas for testing: http://www.veriton.co.uk/roller/fmw/entry/virtualised_oda_proof_of_concept … Frank Munz ?It's not too late - I just submitted two presentations about #OracleWebLogic and #Coherence for the @DOAGeV conference in Nürnberg. Did you? Arun Gupta ?Tyrus 1.0 User Guide: https://tyrus.java.net/documentation/1.0/user-guide.html … #WebSocket #JavaEE7 #GlassFish Arun Gupta #JavaEE7 Launch Webinar Technical Breakout replays on Youtube: http://bit.ly/12uUicT JSON 1.0 , EJB .2, Batch 1.0 more coming! OracleBlogs ?FREE Virtual Developer Day: Java SE, Java EE, Java Emebedded on Jun 19th and 25th http://ow.ly/2xBkwV Markus Eisele #Oracle #JavaSE Critical Patch Update Pre-Release Announcement - June 2013 http://www.oracle.com/technetwork/topics/security/javacpujun2013-1899847.html … #security OracleSupport_WLS ?Simple Custom #JMX MBeans with #WebLogic 12c and #Spring http://pub.vitrue.com/3kEr Oracle Technet Building Java HTML5/WebSocket Applications with JSR 356 - 4pm - Grand Ballroom Salon A/B #qconnewyork WebLogic Community Oracle Fusion Middleware (OFM) 11g (11.1.1.7) Starter Kit available & Customizable Demos http://wp.me/p1LMIb-BK Oracle Technet #Java EE 7: Moving Java Forward for the Enterprise | @java http://pub.vitrue.com/tHiM OTNArchBeat ?Oracle Forms to ADF Modernization Reference - Convero (AMEC) Project | @AndrejusB http://pub.vitrue.com/lZPR WebLogic Community ?ExaLogic In Memory Applications & Whitepapers Building Large Scale E-Commerce Platforms & Rethink the Entire Application Lifecycle… WebLogic Community ?Coherence YouTube videos http://wp.me/p1LMIb-BG Arun Gupta ?WARNING: Next 2 days are going to be loaded with #JavaEE7 launch related tweets, and offline next week! JDeveloper & ADF Using Contextual Event in Oracle ADF http://dlvr.it/3Vpybr Oracle WebLogic Check out new blog on #hybrid_cloud & why choice is important http://bit.ly/1b1QGhL Andrejus Baranovskis Oracle Forms to ADF Modernization Reference - Convero (AMEC) Project http://fb.me/1M9iWNmAw WebLogic Community WebLogic on Oracle Database Appliance by Frances Zhao http://wp.me/p1LMIb-BE OTNArchBeat ?New: A-Team Chronicles >> A great resource for technical content covering Oracle Fusion Middleware / Fusion Apps http://pub.vitrue.com/qbzS Oracle for Partners ?Take Java To The Edge: Java Virtual Developer Day – June 19 & June 25 http://bit.ly/19fGlSX Adam Bien ?Looking forward to tomorrow's #javaee7 + #angularjs #html5 marriage at #jpoint. See you there: http://www.jpoint.nl/meetingpoint/editie-2013#sessie-1 … shay shmeltzer ?There is a new patch for the #Oracle #ADF Mobile extension - use help->check for updates to get it. Frank Munz ?Not using @OracleWebLogic 12c yet? Australia does! Reviews from my @AUSOUG workshops in Brisbane, Adelaide and Perth. http://goo.gl/BfVc4 Arun Gupta ?WebSocket, Server-Sent Events, #JavaEE7 sessions accepted at #jaxlondon ... that's gonna be at least third trip to London this year! WebLogic Community SPARC T5-8 Delivers Best Single System SPECjEnterprise2010 Benchmark running WebLogic 12c http://wp.me/p1LMIb-BC WebLogic Community The Ultimate Java EE Event - 16 Power Workshops mit allen wichtigen Java-EE-Themen http://wp.me/p1LMIb-BY Oracle WebLogic ?@OracleWebLogic 7 Jun New Blog Post: Using try-with-resources with JDBC objects http://ow.ly/2xryb5 JDeveloper & ADF Switching Lists of Values http://dlvr.it/3PbCkw WebLogic Community ?YouTube channel Learning Oracle's ADF http://wp.me/p1LMIb-zA Markus Eisele [GER] RT @heisedc: #Java-Entwicklung in #Oracles Public #Cloud http://heise.de/-1866388/ftw OracleBlogs ?Coherence Incubator & Community Source Code & Release Documentation http://ow.ly/2x2fXK chriscmuir ?New blog post: Migrating ADF Mobile apps from 1.0 to 1.1 https://blogs.oracle.com/onesizedoesntfitall/entry/migrating_adf_mobile_apps_from … JDeveloper & ADF ?ADF JavaScript Partitioning for Performance http://dlvr.it/3Trw15 WebLogic Community WebLogic Server Security Workshop June 27th 2013 Germany http://wp.me/p1LMIb-C7 WebLogic Community Oracle Optimized Solution for WebLogic Server 12c http://wp.me/p1LMIb-BA WebLogic Community Virtualize and Run Your Forms Applications in the Cloud - Now On Demand http://wp.me/p1LMIb-By Lucas Jellema Innteresting presentation on various aspects of end user assistance in Fusion Applications (ADF based): http://www.slideshare.net/uobroin/ouag-ireland-final2012slideshare … Adam Bien ?Summer Of JavaEE Workshops And Gigs: Free Hacking night:11.06.2013, Utrecht JavaEE 7 Meets HTML 5 and AngularJ... http://bit.ly/11XRjt4 WebLogic Community ?Real World ADF Design & Architecture Principles Trainings Germany, Poland & Portugal http://wp.me/p1LMIb-Bw Oracle for Partners ?JAVA Virtual Developer Day – June 19 & June 25 - Watch educational content and engage with Oracle experts online https://oracle.6connex.com/portal/java2013/login/?langR=en_US&mcc=OPNNSL … Markus Eisele ?[blog] Java EE 7 is final. Thoughts, Insights and further Pointers. http://dlvr.it/3SrxnB #javaee7 WebLogic Community Oracle takes the top spot for market share in the Application Server Market Segment for 2012 http://wp.me/p1LMIb-Bu OTNArchBeat ?Oracle ACE Director @LucasJellema is "very pleasantly surprised" with the new ADF Academy. http://pub.vitrue.com/8fad chriscmuir ?Sell out crowd for our ADF architecture course in Munich #adfarch pic.twitter.com/zhNtQJ25JV Markus Eisele ?[blog] New German Article: Java 7 Update 21 Security Improvements http://dlvr.it/3Sc8V9 #java #heise #security Markus Eisele ?[blog] New German Article: Oracle Java Cloud Service http://dlvr.it/3Sc20V #java #heise #OracleCloud OracleSupport_WLS ?Troubleshooting and Tuning with #WebLogic - Developer Webcast now available on #Youtube http://pub.vitrue.com/GSOy Andrejus Baranovskis New ADF Academy - Impressive Concept for ADF eLearning http://fb.me/2kYSMKKR5 OracleSupport_WLS ?Removing a #weblogic domain properly http://pub.vitrue.com/ZndM WebLogic Community WebLogic Partner Community Newsletter May 2013 http://wp.me/p1LMIb-Bp Oracle WebLogic ?Blog: Troubleshooting tools Part 3- Heap Dumps #Oracle #WebLogic Read the series http://bit.ly/14CQSD2 Oracle WebLogic ?Blog: #WebLogic_Server on #Oracle_Database_Appliance- How to conjure a WebLogic cluster- http://bit.ly/11fciHA Oracle WebLogic ?Check out new cool features in Oracle Traffic Director- http://bit.ly/11fbz9h WebLogic Community Additional new material WebLogic Community April 2013 http://wp.me/p1LMIb-zM WebLogic Community New WebLogic references - we want yours http://wp.me/p1LMIb-zK OracleSupport_WLS ?#Weblogic Session Replication jsession ID and F5 http://pub.vitrue.com/dWZp OracleBlogs ?top tweets WebLogic Partner Community May 2013 http://ow.ly/2xc8M5 WebLogic Community Welcome to the Spring edition of Oracle Scene http://wp.me/p1LMIb-zE Andreas Koop ?[blog post] ADF: Static Values View Object does not show any values (solved) http://bit.ly/14RDZ8p OracleBlogs ?ADF Mobile - accessing the SQLite database http://ow.ly/2x85r0 OracleSupport_WLS Youtube channel- Troubleshooting and Tuning with #WebLogic.#JRockit #SOAP #JRF http://pub.vitrue.com/qMxu Arun Gupta Next Java Magazine is all about #JavaEE7...productivity, HTML5, WebSocket, Batch & more. Subscribe http://ow.ly/lkD5D (@Oraclejavamag) Oracle WebLogic How to configure a #WebLogic cluster on #Oracle_Database_Appliance? It’s easy, read how. http://bit.ly/11fciHA Oracle WebLogic ?Blog: How to use Heap Dumps to troubleshooting memory leaks- #Oracle #WebLogic_Server http://bit.ly/14CQSD2 OracleBlogs ?Over 100 Images To Be Added to NetBeans Platform Showcase http://ow.ly/2x7Fvp Lucas Jellema A new release of the ADF EMG Task Flow Tester is now available for both JDeveloper 11 R1 and R2. https://java.net/projects/adf-task-flow-tester/pages/GettingStarted … WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: twitter,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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  • More Fun With Math

    - by PointsToShare
    More Fun with Math   The runaway student – three different ways of solving one problem Here is a problem I read in a Russian site: A student is running away. He is moving at 1 mph. Pursuing him are a lion, a tiger and his math teacher. The lion is 40 miles behind and moving at 6 mph. The tiger is 28 miles behind and moving at 4 mph. His math teacher is 30 miles behind and moving at 5 mph. Who will catch him first? Analysis Obviously we have a set of three problems. They are all basically the same, but the details are different. The problems are of the same class. Here is a little excursion into computer science. One of the things we strive to do is to create solutions for classes of problems rather than individual problems. In your daily routine, you call it re-usability. Not all classes of problems have such solutions. If a class has a general (re-usable) solution, it is called computable. Otherwise it is unsolvable. Within unsolvable classes, we may still solve individual (some but not all) problems, albeit with different approaches to each. Luckily the vast majority of our daily problems are computable, and the 3 problems of our runaway student belong to a computable class. So, let’s solve for the catch-up time by the math teacher, after all she is the most frightening. She might even make the poor runaway solve this very problem – perish the thought! Method 1 – numerical analysis. At 30 miles and 5 mph, it’ll take her 6 hours to come to where the student was to begin with. But by then the student has advanced by 6 miles. 6 miles require 6/5 hours, but by then the student advanced by another 6/5 of a mile as well. And so on and so forth. So what are we to do? One way is to write code and iterate it until we have solved it. But this is an infinite process so we’ll end up with an infinite loop. So what to do? We’ll use the principles of numerical analysis. Any calculator – your computer included – has a limited number of digits. A double floating point number is good for about 14 digits. Nothing can be computed at a greater accuracy than that. This means that we will not iterate ad infinidum, but rather to the point where 2 consecutive iterations yield the same result. When we do financial computations, we don’t even have to go that far. We stop at the 10th of a penny.  It behooves us here to stop at a 10th of a second (100 milliseconds) and this will how we will avoid an infinite loop. Interestingly this alludes to the Zeno paradoxes of motion – in particular “Achilles and the Tortoise”. Zeno says exactly the same. To catch the tortoise, Achilles must always first come to where the tortoise was, but the tortoise keeps moving – hence Achilles will never catch the tortoise and our math teacher (or lion, or tiger) will never catch the student, or the policeman the thief. Here is my resolution to the paradox. The distance and time in each step are smaller and smaller, so the student will be caught. The only thing that is infinite is the iterative solution. The race is a convergent geometric process so the steps are diminishing, but each step in the solution takes the same amount of effort and time so with an infinite number of steps, we’ll spend an eternity solving it.  This BTW is an original thought that I have never seen before. But I digress. Let’s simply write the code to solve the problem. To make sure that it runs everywhere, I’ll do it in JavaScript. function LongCatchUpTime(D, PV, FV) // D is Distance; PV is Pursuers Velocity; FV is Fugitive’ Velocity {     var t = 0;     var T = 0;     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     t = d / pv;     while (t > 0.000001) //a 10th of a second is 1/36,000 of an hour, I used 1/100,000     {         T = T + t;         d = t * fv;         t = d / pv;     }     return T;     } By and large, the higher the Pursuer’s velocity relative to the fugitive, the faster the calculation. Solving this with the 10th of a second limit yields: 7.499999232000001 Method 2 – Geometric Series. Each step in the iteration above is smaller than the next. As you saw, we stopped iterating when the last step was small enough, small enough not to really matter.  When we have a sequence of numbers in which the ratio of each number to its predecessor is fixed we call the sequence geometric. When we are looking at the sum of sequence, we call the sequence of sums series.  Now let’s look at our student and teacher. The teacher runs 5 times faster than the student, so with each iteration the distance between them shrinks to a fifth of what it was before. This is a fixed ratio so we deal with a geometric series.  We normally designate this ratio as q and when q is less than 1 (0 < q < 1) the sum of  + … +  is  – 1) / (q – 1). When q is less than 1, it is easier to use ) / (1 - q). Now, the steps are 6 hours then 6/5 hours then 6/5*5 and so on, so q = 1/5. And the whole series is multiplied by 6. Also because q is less than 1 , 1/  diminishes to 0. So the sum is just  / (1 - q). or 1/ (1 – 1/5) = 1 / (4/5) = 5/4. This times 6 yields 7.5 hours. We can now continue with some algebra and take it back to a simpler formula. This is arduous and I am not going to do it here. Instead let’s do some simpler algebra. Method 3 – Simple Algebra. If the time to capture the fugitive is T and the fugitive travels at 1 mph, then by the time the pursuer catches him he travelled additional T miles. Time is distance divided by speed, so…. (D + T)/V = T  thus D + T = VT  and D = VT – T = (V – 1)T  and T = D/(V – 1) This “strangely” coincides with the solution we just got from the geometric sequence. This is simpler ad faster. Here is the corresponding code. function ShortCatchUpTime(D, PV, FV) {     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     return d / (pv - fv); } The code above, for both the iterative solution and the algebraic solution are actually for a larger class of problems.  In our original problem the student’s velocity (speed) is 1 mph. In the code it may be anything as long as it is less than the pursuer’s velocity. As long as PV > FV, the pursuer will catch up. Here is the really general formula: T = D / (PV – FV) Finally, let’s run the program for each of the pursuers.  It could not be worse. I know he’d rather be eaten alive than suffering through yet another math lesson. See the code run? Select  “Catch Up Time” in www.mgsltns.com/games.htm The host is running on Unix, so the link is case sensitive. That’s All Folks

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  • Emit Knowledge - social network for knowledge sharing

    - by hajan
    Emit Knowledge, as the words refer - it's a social network for emitting / sharing knowledge from users by users. Those who can benefit the most out of this network is perhaps all of YOU who have something to share with others and contribute to the knowledge world. I've been closely communicating with the core team of this very, very interesting, brand new social network (with specific purpose!) about the concept, idea and the vision they have for their product and I can say with a lot of confidence that this network has real potential to become something from which we will all benefit. I won't speak much about that and would prefer to give you link and try it yourself - http://www.emitknowledge.com Mainly, through the past few months I've been testing this network and it is getting improved all the time. The user experience is great, you can easily find out what you need and it follows some known patterns that are common for all social networks. They have some real good ideas and plans that are already under development for the next updates of their product. You can do micro blogging or you can do regular normal blogging… it’s up to you, and the way it works, it is seamless. Here is a short Question and Answers (QA) interview I made with the lead of the team, Marijan Nikolovski: 1. Can you please explain us briefly, what is Emit Knowledge? Emit Knowledge is a brand new knowledge based social network, delivering quality content from users to users. We believe that people’s knowledge, experience and professional thoughts compose quality content, worth sharing among millions around the world. Therefore, we created the platform that matches people’s need to share and gain knowledge in the most suitable and comfortable way. Easy to work with, Emit Knowledge lets you to smoothly craft and emit knowledge around the globe. 2. How 'old' is Emit Knowledge? In hamster’s years we are almost five years old start-up :). Just kidding. We’ve released our public beta about three months ago. Our official release date is 27 of June 2012. 3. How did you come up with this idea? Everything started from a simple idea to solve a complex problem. We’ve seen that the social web has become polluted with data and is on the right track to lose its base principles – socialization and common cause. That was our start point. We’ve gathered the team, drew some sketches and started to mind map the idea. After several idea refactoring’s Emit Knowledge was born. 4. Is there any competition out there in the market? Currently we don't have any competitors that share the same cause. What makes our platform different is the ideology that our product promotes and the functionalities that our platform offers for easy socialization based on interests and knowledge sharing. 5. What are the main technologies used to build Emit Knowledge? Emit Knowledge was built on a heterogeneous pallet of technologies. Currently, we have four of separation: UI – Built on ASP.NET MVC3 and Knockout.js; Messaging infrastructure – Build on top of RabbitMQ; Background services – Our in-house solution for job distribution, orchestration and processing; Data storage – Build on top of MongoDB; What are the main reasons you've chosen ASP.NET MVC? Since all of our team members are .NET engineers, the decision was very natural. ASP.NET MVC is the only Microsoft web stack that sticks to the HTTP behavioral standards. It is easy to work with, have a tiny learning curve and everyone who is familiar with the HTTP will understand its architecture and convention without any difficulties. 6. What are the main reasons for choosing ASP.NET MVC? Since all of our team members are .NET engineers, the decision was very natural. ASP.NET MVC is the only Microsoft web stack that sticks to the HTTP behavioral standards. It is easy to work with, have a tiny learning curve and everyone who is familiar with the HTTP will understand its architecture and convention without any difficulties. 7. Did you use some of the latest Microsoft technologies? If yes, which ones? Yes, we like to rock the cutting edge tech house. Currently we are using Microsoft’s latest technologies like ASP.NET MVC, Web API (work in progress) and the best for the last; we are utilizing Windows Azure IaaS to the bone. 8. Can you please tell us shortly, what would be the benefit of regular bloggers in other blogging platforms to join Emit Knowledge? Well, unless you are some of the smoking ace gurus whose blogs are followed by a large number of users, our platform offers knowledge based segregated community equipped with tools that will enable both current and future users to expand their relations and to self-promote in the community based on their activity and knowledge sharing. 10. I see you are working very intensively and there is already integration with some third-party services to make the process of sharing and emitting knowledge easier, which services did you integrate until now and what do you plan do to next? We have “reemit” functionality for internal sharing and we also support external services like: Twitter; LinkedIn; Facebook; For the regular bloggers we have an extra cream, Windows Live Writer support for easy blog posts emitting. 11. What should we expect next? Currently, we are working on a new fancy community feature. This means that we are going to support user groups to be formed. So for all existing communities and user groups out there, wait us a little bit, we are coming for rescue :). One of the top next features they are developing is the Community Feature. It means, if you have your own User Group, Community Group or any other Group on which you and your users are mostly blogging or sharing (emitting) knowledge in various ways, Emit Knowledge as a platform will help you have everything you need to promote your group, make new followers and host all the necessary stuff that you have had need of. I would invite you to try the network and start sharing knowledge in a way that will help you gather new followers and spread your knowledge faster, easier and in a more efficient way! Let’s Emit Knowledge!

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  • DRY and SRP

    - by Timothy Klenke
    Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

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  • CodePlex Daily Summary for Saturday, June 16, 2012

    CodePlex Daily Summary for Saturday, June 16, 2012Popular ReleasesCosmos (C# Open Source Managed Operating System): Release 92560: Prerequisites Visual Studio 2010 - Any version including Express. Express users must also install Visual Studio 2010 Integrated Shell runtime VMWare - Cosmos can run on real hardware as well as other virtualization environments but our default debug setup is configured for VMWare. VMWare Player (Free). or Workstation VMWare VIX API 1.11AutoUpdaterdotNET : Autoupdate for VB.NET and C# Developer: AutoUpdater.NET 1.1: Release Notes *New feature added that allows user to select remind later interval.Sumzlib: API document: API documentMicrosoft SQL Server Product Samples: Database: AdventureWorks 2008 OLTP Script: Install AdventureWorks2008 OLTP database from script The AdventureWorks database can be created by running the instawdb.sql DDL script contained in the AdventureWorks 2008 OLTP Script.zip file. The instawdb.sql script depends on two path environment variables: SqlSamplesDatabasePath and SqlSamplesSourceDataPath. The SqlSamplesDatabasePath environment variable is set to the default Microsoft ® SQL Server 2008 path. You will need to change the SqlSamplesSourceDataPath environment variable to th...HigLabo: HigLabo_20120613: Bug fix HigLabo.Mail Decode header encoded by CP1252Jasc (just another script compressor): 1.3.1: Updated Ajax Minifier to 4.55.WipeTouch, a jQuery touch plugin: 1.2.0: Changes since 1.1.0: New: wipeMove event, triggered while moving the mouse/finger. New: added "source" to the result object. Bug fix: sometimes vertical wipe events would not trigger correctly. Bug fix: improved tapToClick handler. General code refactoring. Windows Phone 7 is not supported, yet! Its behaviour is completely broken and would require some special tricks to make it work. Maybe in the future...Phalanger - The PHP Language Compiler for the .NET Framework: 3.0.0.3026 (June 2012): Fixes: round( 0.0 ) local TimeZone name TimeZone search compiling multi-script-assemblies PhpString serialization DocDocument::loadHTMLFile() token_get_all() parse_url()BlackJumboDog: Ver5.6.4: 2012.06.13 Ver5.6.4  (1) Web???????、???POST??????????????????Yahoo! UI Library: YUI Compressor for .Net: Version 2.0.0.0 - Ferret: - Merging both 3.5 and 2.0 codebases to a single .NET 2.0 assembly. - MSBuild Task. - NAnt Task.Bumblebee: Version 0.3.1: Changed default config values to decent ones. Restricted visibility of Hive.fs to internal. Added some XML documentation. Added Array.shuffle utility. The dll is also available on NuGet My apologies, the initial source code referenced was missing one file which prevented it from building The source code contains two examples, one in C#, one in F#, illustrating the usage of the framework on the Travelling Salesman Problem: Source CodeSharePoint XSL Templates: SPXSLT 0.0.9: Added new template FixAmpersands. Fixed the contents of the MultiSelectValueCheck.xsl file, which was missing the stylesheet wrapper.ExcelFileEditor: .CS File: nothingBizTalk Scheduled Task Adapter: Release 4.0: Works with BizTalk Server 2010. Compiled in .NET Framework 4.0. In this new version are available small improvements compared to the current version (3.0). We can highlight the following improvements or changes: 24 hours support in “start time” property. Previous versions had an issue with setting the start time, as it shown 12 hours watch but no AM/PM. Daily scheduler review. Solved a small bug on Daily Properties: unable to switch between “Every day” and “on these days” Installation e...Weapsy - ASP.NET MVC CMS: 1.0.0 RC: - Upgrade to Entity Framework 4.3.1 - Added AutoMapper custom version (by nopCommerce Team) - Added missed model properties and localization resources of Plugin Definitions - Minor changes - Fixed some bugsXenta Framework - extensible enterprise n-tier application framework: Xenta Framework 1.8.0 Beta: Catalog and Publication reviews and ratings Store language packs in data base Improve reporting system Improve Import/Export system A lot of WebAdmin app UI improvements Initial implementation of the WebForum app DB indexes Improve and simplify architecture Less abstractions Modernize architecture Improve, simplify and unify API Simplify and improve testing A lot of new unit tests Codebase refactoring and ReSharpering Utilize Castle Windsor Utilize NHibernate ORM ...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.55: Properly handle IE extension to CSS3 grammar that allows for multiple parameters to functional pseudo-class selectors. add new switch -braces:(new|same) that affects where opening braces are placed in multi-line output. The default, "new" puts them on their own new line; "same" outputs them at the end of the previous line. add new optional values to the -inline switch: -inline:(force|noforce), which can be combined with the existing boolean value via comma-separators; value "force" (which...Microsoft Media Platform: Player Framework: MMP Player Framework 2.7 (Silverlight and WP7): Additional DownloadsSMFv2.7 Full Installer (MSI) - This will install everything you need in order to develop your own SMF player application, including the IIS Smooth Streaming Client. It only includes the assemblies. If you want the source code please follow the link above. Smooth Streaming Sample Player - This is a pre-built player that includes support for IIS Smooth Streaming. You can configure the player to playback your content by simplying editing a configuration file - no need to co...Liberty: v3.2.1.0 Release 10th June 2012: Change Log -Added -Liberty is now digitally signed! If the certificate on Liberty.exe is missing, invalid, or does not state that it was developed by "Xbox Chaos, Open Source Developer," your copy of Liberty may have been altered in some (possibly malicious) way. -Reach Mass biped max health and shield changer -Fixed -H3/ODST Fixed all of the glitches that users kept reporting (also reverted the changes made in 3.2.0.2) -Reach Made some tag names clearer and more consistent between m...Media Companion: Media Companion 3.503b: It has been a while, so it's about time we release another build! Major effort has been for fixing trailer downloads, plus a little bit of work for episode guide tag in TV show NFOs.New Projects.NinJa (dotNinja): An extensive JavaScript Framework revolving around principles found in .NET and aiming to integrate full Intellisense support. bab-rizg: solve unemployment problemBizTalk Multi-part Message Attachments Zipper Pipeline Component: This pipeline component replaces all attachments of a multi-part message, in a send pipeline, for its zipped equivalent.Boggle.Net: A basic implementation of Boggle for WPF.CFScript: CFScript is an ANT-like scripting system for Compact Framework. Tasks like copying files, setting registry values o install CAB files can be done with CFScript.Diablo3: Diablo3Dygraphs.NET: Dygraphs.NETDynamics CRM plugin for nopCommerce: This plugins is a bridge between nopCommerce and Dynamics CRM. nms.gaming: Place holderProject Bright Star: Project Bright Star. Deal with it.RDFSharp: RDFSharp is a library designed to ease the development of .NET applications based on the RDF and Semantic Web data model.SlamCMS: An application framework that allows you to build content managed sites leveraging SharePoint 2010 for publishing with tools to query and manifest your data.test02: no

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  • Book Review: Brownfield Application Development in .NET

    - by DotNetBlues
    I recently finished reading the book Brownfield Application Development in .NET by Kyle Baley and Donald Belcham.  The book is available from Manning.  First off, let me say that I'm a huge fan of Manning as a publisher.  I've found their books to be top-quality, over all.  As a Kindle owner, I also appreciate getting an ebook copy along with the dead tree copy.  I find ebooks to be much more convenient to read, but hard-copies are easier to reference. The book covers, surprisingly enough, working with brownfield applications.  Which is well and good, if that term has meaning to you.  It didn't for me.  Without retreading a chunk of the first chapter, the authors break code bases into three broad categories: greenfield, brownfield, and legacy.  Greenfield is, essentially, new development that hasn't had time to rust and is (hopefully) being approached with some discipline.  Legacy applications are those that are more or less stable and functional, that do not expect to see a lot of work done to them, and are more likely to be replaced than reworked. Brownfield code is the gray (brown?) area between the two and the authors argue, quite effectively, that it is the most likely state for an application to be in.  Brownfield code has, in some way, been allowed to tarnish around the edges and can be difficult to work with.  Although I hadn't realized it, most of the code I've worked on has been brownfield.  Sometimes, there's talk of scrapping and starting over.  Sometimes, the team dismisses increased discipline as ivory tower nonsense.  And, sometimes, I've been the ignorant culprit vexing my future self. The book is broken into two major sections, plus an introduction chapter and an appendix.  The first section covers what the authors refer to as "The Ecosystem" which consists of version control, build and integration, testing, metrics, and defect management.  The second section is on actually writing code for brownfield applications and discusses object-oriented principles, architecture, external dependencies, and, of course, how to deal with these when coming into an existing code base. The ecosystem section is just shy of 140 pages long and brings some real meat to the matter.  The focus on "pain points" immediately sets the tone as problem-solution, rather than academic.  The authors also approach some of the topics from a different angle than some essays I've read on similar topics.  For example, the chapter on automated testing is on just that -- automated testing.  It's all well and good to criticize a project as conflating integration tests with unit tests, but it really doesn't make anyone's life better.  The discussion on testing is more focused on the "right" level of testing for existing projects.  Sometimes, an integration test is the best you can do without gutting a section of functional code.  Even if you can sell other developers and/or management on doing so, it doesn't actually provide benefit to your customers to rewrite code that works.  This isn't to say the authors encourage sloppy coding.  Far from it.  Just that they point out the wisdom of ignoring the sleeping bear until after you deal with the snarling wolf. The other sections take a similarly real-world, workable approach to the pain points they address.  As the section moves from technical solutions like version control and continuous integration (CI) to the softer, process issues of metrics and defect tracking, the authors begin to gently suggest moving toward a zero defect count.  While that really sounds like an unreasonable goal for a lot of ongoing projects, it's quite apparent that the authors have first-hand experience with taming some gruesome projects.  The suggestions are grounded and workable, and the difficulty of some situations is explicitly acknowledged. I have to admit that I started getting bored by the end of the ecosystem section.  No matter how valuable I think a good project manager or business analyst is to a successful ALM, at the end of the day, I'm a gear-head.  Also, while I agreed with a lot of the ecosystem ideas, in theory, I didn't necessarily feel that a lot of the single-developer projects that I'm often involved in really needed that level of rigor.  It's only after reading the sidebars and commentary in the coding section that I had the context for the arguments made in favor of a strong ecosystem supporting the development process.  That isn't to say that I didn't support good product management -- indeed, I've probably pushed too hard, on occasion, for a strong ALM outside of just development.  This book gave me deeper insight into why some corners shouldn't be cut and how damaging certain sins of omission can be. The code section, though, kept me engaged for its entirety.  Many technical books can be used as reference material from day one.  The authors were clear, however, that this book is not one of these.  The first chapter of the section (chapter seven, over all) addresses object oriented (OO) practices.  I've read any number of definitions, discussions, and treatises on OO.  None of the chapter was new to me, but it was a good review, and I'm of the opinion that it's good to review the foundations of what you do, from time to time, so I didn't mind. The remainder of the book is really just about how to apply OOP to existing code -- and, just because all your code exists in classes does not mean that it's object oriented.  That topic has the potential to be extremely condescending, but the authors miraculously managed to never once make me feel like a dolt or that they were wagging their finger at me for my prior sins.  Instead, they continue the "pain points" and problem-solution presentation to give concrete examples of how to apply some pretty academic-sounding ideas.  That's a point worth emphasizing, as my experience with most OO discussions is that they stay in the academic realm.  This book gives some very, very good explanations of why things like the Liskov Substitution Principle exist and why a corporate programmer should even care.  Even if you know, with absolute certainty, that you'll never have to work on an existing code-base, I would recommend this book just for the clarity it provides on OOP. This book goes beyond just theory, or even real-world application.  It presents some methods for fixing problems that any developer can, and probably will, encounter in the wild.  First, the authors address refactoring application layers and internal dependencies.  Then, they take you through those layers from the UI to the data access layer and external dependencies.  Finally, they come full circle to tie it all back to the overall process.  By the time the book is done, you're left with a lot of ideas, but also a reasonable plan to begin to improve an existing project structure. Throughout the book, it's apparent that the authors have their own preferred methodology (TDD and domain-driven design), as well as some preferred tools.  The "Our .NET Toolbox" is something of a neon sign pointing to that latter point.  They do not beat the reader over the head with anything resembling a "One True Way" mentality.  Even for the most emphatic points, the tone is quite congenial and helpful.  With some of the near-theological divides that exist within the tech community, I found this to be one of the more remarkable characteristics of the book.  Although the authors favor tools that might be considered Alt.NET, there is no reason the advice and techniques given couldn't be quite successful in a pure Microsoft shop with Team Foundation Server.  For that matter, even though the book specifically addresses .NET, it could be applied to a Java and Oracle shop, as well.

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  • Computer Networks UNISA - Chap 10 &ndash; In Depth TCP/IP Networking

    - by MarkPearl
    After reading this section you should be able to Understand methods of network design unique to TCP/IP networks, including subnetting, CIDR, and address translation Explain the differences between public and private TCP/IP networks Describe protocols used between mail clients and mail servers, including SMTP, POP3, and IMAP4 Employ multiple TCP/IP utilities for network discovery and troubleshooting Designing TCP/IP-Based Networks The following sections explain how network and host information in an IPv4 address can be manipulated to subdivide networks into smaller segments. Subnetting Subnetting separates a network into multiple logically defined segments, or subnets. Networks are commonly subnetted according to geographic locations, departmental boundaries, or technology types. A network administrator might separate traffic to accomplish the following… Enhance security Improve performance Simplify troubleshooting The challenges of Classful Addressing in IPv4 (No subnetting) The simplest type of IPv4 is known as classful addressing (which was the Class A, Class B & Class C network addresses). Classful addressing has the following limitations. Restriction in the number of usable IPv4 addresses (class C would be limited to 254 addresses) Difficult to separate traffic from various parts of a network Because of the above reasons, subnetting was introduced. IPv4 Subnet Masks Subnetting depends on the use of subnet masks to identify how a network is subdivided. A subnet mask indicates where network information is located in an IPv4 address. The 1 in a subnet mask indicates that corresponding bits in the IPv4 address contain network information (likewise 0 indicates the opposite) Each network class is associated with a default subnet mask… Class A = 255.0.0.0 Class B = 255.255.0.0 Class C = 255.255.255.0 An example of calculating  the network ID for a particular device with a subnet mask is shown below.. IP Address = 199.34.89.127 Subnet Mask = 255.255.255.0 Resultant Network ID = 199.34.89.0 IPv4 Subnetting Techniques Subnetting breaks the rules of classful IPv4 addressing. Read page 490 for a detailed explanation Calculating IPv4 Subnets Read page 491 – 494 for an explanation Important… Subnetting only applies to the devices internal to your network. Everything external looks at the class of the IP address instead of the subnet network ID. This way, traffic directed to your network externally still knows where to go, and once it has entered your internal network it can then be prioritized and segmented. CIDR (classless Interdomain Routing) CIDR is also known as classless routing or supernetting. In CIDR conventional network class distinctions do not exist, a subnet boundary can move to the left, therefore generating more usable IP addresses on your network. A subnet created by moving the subnet boundary to the left is known as a supernet. With CIDR also came new shorthand for denoting the position of subnet boundaries known as CIDR notation or slash notation. CIDR notation takes the form of the network ID followed by a forward slash (/) followed by the number of bits that are used for the extended network prefix. To take advantage of classless routing, your networks routers must be able to interpret IP addresses that don;t adhere to conventional network class parameters. Routers that rely on older routing protocols (i.e. RIP) are not capable of interpreting classless IP addresses. Internet Gateways Gateways are a combination of software and hardware that enable two different network segments to exchange data. A gateway facilitates communication between different networks or subnets. Because on device cannot send data directly to a device on another subnet, a gateway must intercede and hand off the information. Every device on a TCP/IP based network has a default gateway (a gateway that first interprets its outbound requests to other subnets, and then interprets its inbound requests from other subnets). The internet contains a vast number of routers and gateways. If each gateway had to track addressing information for every other gateway on the Internet, it would be overtaxed. Instead, each handles only a relatively small amount of addressing information, which it uses to forward data to another gateway that knows more about the data’s destination. The gateways that make up the internet backbone are called core gateways. Address Translation An organizations default gateway can also be used to “hide” the organizations internal IP addresses and keep them from being recognized on a public network. A public network is one that any user may access with little or no restrictions. On private networks, hiding IP addresses allows network managers more flexibility in assigning addresses. Clients behind a gateway may use any IP addressing scheme, regardless of whether it is recognized as legitimate by the Internet authorities but as soon as those devices need to go on the internet, they must have legitimate IP addresses to exchange data. When a clients transmission reaches the default gateway, the gateway opens the IP datagram and replaces the client’s private IP address with an Internet recognized IP address. This process is known as NAT (Network Address Translation). TCP/IP Mail Services All Internet mail services rely on the same principles of mail delivery, storage, and pickup, though they may use different types of software to accomplish these functions. Email servers and clients communicate through special TCP/IP application layer protocols. These protocols, all of which operate on a variety of operating systems are discussed below… SMTP (Simple Mail transfer Protocol) The protocol responsible for moving messages from one mail server to another over TCP/IP based networks. SMTP belongs to the application layer of the ODI model and relies on TCP as its transport protocol. Operates from port 25 on the SMTP server Simple sub-protocol, incapable of doing anything more than transporting mail or holding it in a queue MIME (Multipurpose Internet Mail Extensions) The standard message format specified by SMTP allows for lines that contain no more than 1000 ascii characters meaning if you relied solely on SMTP you would have very short messages and nothing like pictures included in an email. MIME us a standard for encoding and interpreting binary files, images, video, and non-ascii character sets within an email message. MIME identifies each element of a mail message according to content type. MIME does not replace SMTP but works in conjunction with it. Most modern email clients and servers support MIME POP (Post Office Protocol) POP is an application layer protocol used to retrieve messages from a mail server POP3 relies on TCP and operates over port 110 With POP3 mail is delivered and stored on a mail server until it is downloaded by a user Disadvantage of POP3 is that it typically does not allow users to save their messages on the server because of this IMAP is sometimes used IMAP (Internet Message Access Protocol) IMAP is a retrieval protocol that was developed as a more sophisticated alternative to POP3 The single biggest advantage IMAP4 has over POP3 is that users can store messages on the mail server, rather than having to continually download them Users can retrieve all or only a portion of any mail message Users can review their messages and delete them while the messages remain on the server Users can create sophisticated methods of organizing messages on the server Users can share a mailbox in a central location Disadvantages of IMAP are typically related to the fact that it requires more storage space on the server. Additional TCP/IP Utilities Nearly all TCP/IP utilities can be accessed from the command prompt on any type of server or client running TCP/IP. The syntaxt may differ depending on the OS of the client. Below is a list of additional TCP/IP utilities – research their use on your own! Ipconfig (Windows) & Ifconfig (Linux) Netstat Nbtstat Hostname, Host & Nslookup Dig (Linux) Whois (Linux) Traceroute (Tracert) Mtr (my traceroute) Route

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  • CodePlex Daily Summary for Wednesday, October 02, 2013

    CodePlex Daily Summary for Wednesday, October 02, 2013Popular ReleasesEla, functional programming language: Ela, dynamic functional language (PDF, book, 0.6): A book about Ela, dynamic functional language in PDF format.Compact 2013 Tools: Managed Code Version of Apps 1.0: Compact13MinShell Download https://download-codeplex.sec.s-msft.com/Images/v20779/RuntimeBinary.gif Compact13MinShellV3.0.zip The Codeplex Project Downloads Page AboutCompact13Tools.zip: Each app as an OS Content Subproject. Includes CoreCon3 Subproject. Apps.zip: Just the apps in a a zip file AppInstallersx86.zip: The apps as separate x86 installers Compact13MinShell Download: (Separate Codeplex Project) The Minshell that implements the menu that includes these apps via registr...Application Architecture Guidelines: App Architecture Guidelines 3.0.8: This document is an overview of software qualities, principles, patterns, practices, tools and libraries.C# Intellisense for Notepad++: Release v1.0.7.0: - smart indentation - document formatting To avoid the DLLs getting locked by OS use MSI file for the installation.CS-Script for Notepad++: Release v1.0.7.0: - smart indentation - document formatting To avoid the DLLs getting locked by OS use MSI file for the installation.State of Decay Save Manager: Version 1.0.2: Added Start/Stop button for timer to manually enable/disable Quick save routine updated to force it to refresh the folder date Quick save added to backup listing Manual update button Lower level hooking for F5 and F9 buttons workingSharePoint Farm documentation tool: SPDocumentor 0.1: SPDocumentor 0.1 This is a POC version of the tool that will be implemented.DotNetNuke® Form and List: 06.00.06: DotNetNuke Form and List 06.00.06 Changes to 6.0.6•Add in Sql to remove 'text on row' setting for UserDefinedTable to make SQL Azure compatible. •Add new azureCompatible element to manifest. •Added a fix for importing templates. Changes to 6.0.2•Fix: MakeThumbnail was broken if the application pool was configured to .Net 4 •Change: Data is now stored in nvarchar(max) instead of ntext Changes to 6.0.1•Scripts now compatible with SQL Azure. Changes to 6.0.0•Icons are shown in module action b...BlackJumboDog: Ver5.9.6: 2013.09.30 Ver5.9.6 (1)SMTP???????、???????????????? (2)WinAPI??????? (3)Web???????CGI???????????????????????Microsoft Ajax Minifier: Microsoft Ajax Minifier 5.2: Mostly internal code tweaks. added -nosize switch to turn off the size- and gzip-calculations done after minification. removed the comments in the build targets script for the old AjaxMin build task (discussion #458831). Fixed an issue with extended Unicode characters encoded inside a string literal with adjacent \uHHHH\uHHHH sequences. Fixed an IndexOutOfRange exception when encountering a CSS identifier that's a single underscore character (_). In previous builds, the net35 and net20...AJAX Control Toolkit: September 2013 Release: AJAX Control Toolkit Release Notes - September 2013 Release (Updated) Version 7.1001September 2013 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4.5 – AJAX Control Toolkit for .NET 4.5 and sample site (Recommended). AJAX Control Toolkit .NET 4 – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Important UpdateThis release has been updated to fix two issues: Upda...WDTVHubGen - Adds Metadata, thumbnails and subtitles to WDTV Live Hubs: WDTVHubGen.v2.1.4.apifix-alpha: WDTVHubGen.v2.1.4.apifix-alpha is for testers to figure out if we got the NEW api plugged in ok. thanksVisual Log Parser: VisualLogParser: Portable Visual Log Parser for Dotnet 4.0Trace Reader for Microsoft Dynamics CRM: Trace Reader (1.2013.9.29): Initial releaseAudioWordsDownloader: AudioWordsDownloader 1.1 build 88: New features list of words (mp3 files) is available upon typing when a download path is defined list of download paths is added paths history settings added Bug fixed case mismatch in word search field fixed path not exist bug fixed when history has been used path, when filled from dialog, not stored refresh autocomplete list after path change word sought is deleted when path is changed at the end sought word list is deleted word list not refreshed download ends. word lis...Wsus Package Publisher: Release v1.3.1309.28: Fix a bug, where WPP crash when running on a computer where Windows was installed in another language than Fr, En or De, and launching the Update Creation Wizard. Fix a bug, where WPP crash if some Multi-Thread job are launch with more than 64 items. Add a button to abort "Install This Update" wizard. Allow WPP to remember which columns are shown last time. Make URL clickable on the Update Information Tab. Add a new feature, when Double-Clicking on an update, the default action exec...Tweetinvi a friendly Twitter C# API: Alpha 0.8.3.0: Version 0.8.3.0 emphasis on the FIlteredStream and ease how to manage Exceptions that can occur due to the network or any other issue you might encounter. Will be available through nuget the 29/09/2013. FilteredStream Features provided by the Twitter Stream API - Ability to track specific keywords - Ability to track specific users - Ability to track specific locations Additional features - Detect the reasons the tweet has been retrieved from the Filtered API. You have access to both the ma...AcDown?????: AcDown????? v4.5: ??●AcDown??????????、??、??、???????。????,????,?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????,??????、????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ??v4.5 ???? AcPlay????????v3.5 ????????,???????????30% ?? ???????GoodManga.net???? ?? ?????????? ?? ??Acfun?????????? ??Bilibili??????????? ?????????flvcd???????? ??SfAcg????????????? ???????????? ???????????????? ????32...Magick.NET: Magick.NET 6.8.7.001: Magick.NET linked with ImageMagick 6.8.7.0. Breaking changes: - ToBitmap method of MagickImage returns a png instead of a bmp. - Changed the value for full transparency from 255(Q8)/65535(Q16) to 0. - MagickColor now uses floats instead of Byte/UInt16.Media Companion: Media Companion MC3.578b: With the feedback received over the renaming of Movie Folders, and files, there has been some refinement done. As well as I would like to introduce Blu-Ray movie folder support, for Pre-Frodo and Frodo onwards versions of XBMC. To start with, Context menu option for renaming movies, now has three sub options: Movie & Folder, Movie only & Folder only. The option Manual Movie Rename needs to be selected from Movie Preferences, but the autoscrape boxes do not need to be selected. Blu Ray Fo...New ProjectsAll CRM Resources for Microsoft Dynamics CRM: Microsoft Dynamics CRM Resources Windows 8 App with News, Feeds, Forums, Blogs, Videos & Twitter updates, information, guides & resources #MSDynCRM community.BasiliskBugTracker: A sample teamwork project for the Telerik Academy's ASP.NET Course 2013.CagerAutoPilot: Programmatically control a toy helicopter with kinectClass Libraries & Database Management: ClassDBManager permette la sincronizzazione delle classi (creazione/modifica/cancellazione) in base alle tabelle contenute nel databaseCommand Line Utility: Enables fast, easy creation of object-oriented settings classes in C# that interface directly with command line input. Minimize code and increase robustness.Controles | Versa: Login Pagina Principal Cadastro UsuáriosDispage: DisPage is a system to hide a website under a different browser title (For example "Vimeo" could look like "Google" (I am working on a way of changing this)ExpressiveDataGenerators: Expressive and powerfull test data generators.Fabrikam Fiber: This project provides download and support to anyone (i.e. trainers) who want to access the Fabrikam Fiber sample application, setup scripts, notes, etc.Get all numbers in between a pair of numbers: Get all integers between two numbers. C#, VB.NETHungryCrowd food lovers market: food lovers market, food, marketsInvalid User Details for SharePoint 2007 and 2010 Sites: Client Based Utility to export invalid users from a SharePoint site (2007 and 2010), as a CSV file using native SP Web Services (UserGroup.asmx and People.asmx)Kh?o Sát Công Ngh?: 1. Tên d? tài: Th?c tr?ng và gi?i pháp h? tr? nâng cao nang l?c c?nh tranh c?a các doanh nghi?p nh? và v?a t?nh Thanh Hóa Lightning: Micro toolkit to make it easy to get content on your site, and serve it fast.LovelyCMS: LovelyCMS ist ein sehr einfaches Content Management System auf der Basis von ASP.NET MVC4.MVC Error Handler: Simple library that allows you to easily create error pages for common HTTP error and application exceptions.MVC Table Styling selection to CSS and demo table: Enter table styling by selection from drop-down list and both generated CSS and see effect of the CSS on a demo table.MvcWebApiFramework: main frameworkNoDemo: It is not only a demo.NumbersInWordsRU: ?????? ??? ??????????? ????? ??????? ? ????? ????????Omnifactotum: Omnifactotum is the .NET library intended to help .NET developers avoid writing the same helper types, methods and extension methods for different projects.Outlook Rules Offline Processor: A utility for organizing Microsoft Outlook rules. The utility uses the rules export file, *.RWZ, to make changes.SharePoint Farm documentation tool: The SPDocumentor (SharePoint Farm documentation tool) allows you to generate a word document that includes most of your farm settings. Startup Shutdown Mailer: This tool is a simple Windows Service which sends an e-mail to a specified account whenever your PC was started up or shut down.YüzKitabi: Daha güvenli ve etkilesimli YüzKitabi Uygulamasi

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  • How to Reuse Your Old Wi-Fi Router as a Network Switch

    - by Jason Fitzpatrick
    Just because your old Wi-Fi router has been replaced by a newer model doesn’t mean it needs to gather dust in the closet. Read on as we show you how to take an old and underpowered Wi-Fi router and turn it into a respectable network switch (saving your $20 in the process). Image by mmgallan. Why Do I Want To Do This? Wi-Fi technology has changed significantly in the last ten years but Ethernet-based networking has changed very little. As such, a Wi-Fi router with 2006-era guts is lagging significantly behind current Wi-Fi router technology, but the Ethernet networking component of the device is just as useful as ever; aside from potentially being only 100Mbs instead of 1000Mbs capable (which for 99% of home applications is irrelevant) Ethernet is Ethernet. What does this matter to you, the consumer? It means that even though your old router doesn’t hack it for your Wi-Fi needs any longer the device is still a perfectly serviceable (and high quality) network switch. When do you need a network switch? Any time you want to share an Ethernet cable among multiple devices, you need a switch. For example, let’s say you have a single Ethernet wall jack behind your entertainment center. Unfortunately you have four devices that you want to link to your local network via hardline including your smart HDTV, DVR, Xbox, and a little Raspberry Pi running XBMC. Instead of spending $20-30 to purchase a brand new switch of comparable build quality to your old Wi-Fi router it makes financial sense (and is environmentally friendly) to invest five minutes of your time tweaking the settings on the old router to turn it from a Wi-Fi access point and routing tool into a network switch–perfect for dropping behind your entertainment center so that your DVR, Xbox, and media center computer can all share an Ethernet connection. What Do I Need? For this tutorial you’ll need a few things, all of which you likely have readily on hand or are free for download. To follow the basic portion of the tutorial, you’ll need the following: 1 Wi-Fi router with Ethernet ports 1 Computer with Ethernet jack 1 Ethernet cable For the advanced tutorial you’ll need all of those things, plus: 1 copy of DD-WRT firmware for your Wi-Fi router We’re conducting the experiment with a Linksys WRT54GL Wi-Fi router. The WRT54 series is one of the best selling Wi-Fi router series of all time and there’s a good chance a significant number of readers have one (or more) of them stuffed in an office closet. Even if you don’t have one of the WRT54 series routers, however, the principles we’re outlining here apply to all Wi-Fi routers; as long as your router administration panel allows the necessary changes you can follow right along with us. A quick note on the difference between the basic and advanced versions of this tutorial before we proceed. Your typical Wi-Fi router has 5 Ethernet ports on the back: 1 labeled “Internet”, “WAN”, or a variation thereof and intended to be connected to your DSL/Cable modem, and 4 labeled 1-4 intended to connect Ethernet devices like computers, printers, and game consoles directly to the Wi-Fi router. When you convert a Wi-Fi router to a switch, in most situations, you’ll lose two port as the “Internet” port cannot be used as a normal switch port and one of the switch ports becomes the input port for the Ethernet cable linking the switch to the main network. This means, referencing the diagram above, you’d lose the WAN port and LAN port 1, but retain LAN ports 2, 3, and 4 for use. If you only need to switch for 2-3 devices this may be satisfactory. However, for those of you that would prefer a more traditional switch setup where there is a dedicated WAN port and the rest of the ports are accessible, you’ll need to flash a third-party router firmware like the powerful DD-WRT onto your device. Doing so opens up the router to a greater degree of modification and allows you to assign the previously reserved WAN port to the switch, thus opening up LAN ports 1-4. Even if you don’t intend to use that extra port, DD-WRT offers you so many more options that it’s worth the extra few steps. Preparing Your Router for Life as a Switch Before we jump right in to shutting down the Wi-Fi functionality and repurposing your device as a network switch, there are a few important prep steps to attend to. First, you want to reset the router (if you just flashed a new firmware to your router, skip this step). Following the reset procedures for your particular router or go with what is known as the “Peacock Method” wherein you hold down the reset button for thirty seconds, unplug the router and wait (while still holding the reset button) for thirty seconds, and then plug it in while, again, continuing to hold down the rest button. Over the life of a router there are a variety of changes made, big and small, so it’s best to wipe them all back to the factory default before repurposing the router as a switch. Second, after resetting, we need to change the IP address of the device on the local network to an address which does not directly conflict with the new router. The typical default IP address for a home router is 192.168.1.1; if you ever need to get back into the administration panel of the router-turned-switch to check on things or make changes it will be a real hassle if the IP address of the device conflicts with the new home router. The simplest way to deal with this is to assign an address close to the actual router address but outside the range of addresses that your router will assign via the DHCP client; a good pick then is 192.168.1.2. Once the router is reset (or re-flashed) and has been assigned a new IP address, it’s time to configure it as a switch. Basic Router to Switch Configuration If you don’t want to (or need to) flash new firmware onto your device to open up that extra port, this is the section of the tutorial for you: we’ll cover how to take a stock router, our previously mentioned WRT54 series Linksys, and convert it to a switch. Hook the Wi-Fi router up to the network via one of the LAN ports (consider the WAN port as good as dead from this point forward, unless you start using the router in its traditional function again or later flash a more advanced firmware to the device, the port is officially retired at this point). Open the administration control panel via  web browser on a connected computer. Before we get started two things: first,  anything we don’t explicitly instruct you to change should be left in the default factory-reset setting as you find it, and two, change the settings in the order we list them as some settings can’t be changed after certain features are disabled. To start, let’s navigate to Setup ->Basic Setup. Here you need to change the following things: Local IP Address: [different than the primary router, e.g. 192.168.1.2] Subnet Mask: [same as the primary router, e.g. 255.255.255.0] DHCP Server: Disable Save with the “Save Settings” button and then navigate to Setup -> Advanced Routing: Operating Mode: Router This particular setting is very counterintuitive. The “Operating Mode” toggle tells the device whether or not it should enable the Network Address Translation (NAT)  feature. Because we’re turning a smart piece of networking hardware into a relatively dumb one, we don’t need this feature so we switch from Gateway mode (NAT on) to Router mode (NAT off). Our next stop is Wireless -> Basic Wireless Settings: Wireless SSID Broadcast: Disable Wireless Network Mode: Disabled After disabling the wireless we’re going to, again, do something counterintuitive. Navigate to Wireless -> Wireless Security and set the following parameters: Security Mode: WPA2 Personal WPA Algorithms: TKIP+AES WPA Shared Key: [select some random string of letters, numbers, and symbols like JF#d$di!Hdgio890] Now you may be asking yourself, why on Earth are we setting a rather secure Wi-Fi configuration on a Wi-Fi router we’re not going to use as a Wi-Fi node? On the off chance that something strange happens after, say, a power outage when your router-turned-switch cycles on and off a bunch of times and the Wi-Fi functionality is activated we don’t want to be running the Wi-Fi node wide open and granting unfettered access to your network. While the chances of this are next-to-nonexistent, it takes only a few seconds to apply the security measure so there’s little reason not to. Save your changes and navigate to Security ->Firewall. Uncheck everything but Filter Multicast Firewall Protect: Disable At this point you can save your changes again, review the changes you’ve made to ensure they all stuck, and then deploy your “new” switch wherever it is needed. Advanced Router to Switch Configuration For the advanced configuration, you’ll need a copy of DD-WRT installed on your router. Although doing so is an extra few steps, it gives you a lot more control over the process and liberates an extra port on the device. Hook the Wi-Fi router up to the network via one of the LAN ports (later you can switch the cable to the WAN port). Open the administration control panel via web browser on the connected computer. Navigate to the Setup -> Basic Setup tab to get started. In the Basic Setup tab, ensure the following settings are adjusted. The setting changes are not optional and are required to turn the Wi-Fi router into a switch. WAN Connection Type: Disabled Local IP Address: [different than the primary router, e.g. 192.168.1.2] Subnet Mask: [same as the primary router, e.g. 255.255.255.0] DHCP Server: Disable In addition to disabling the DHCP server, also uncheck all the DNSMasq boxes as the bottom of the DHCP sub-menu. If you want to activate the extra port (and why wouldn’t you), in the WAN port section: Assign WAN Port to Switch [X] At this point the router has become a switch and you have access to the WAN port so the LAN ports are all free. Since we’re already in the control panel, however, we might as well flip a few optional toggles that further lock down the switch and prevent something odd from happening. The optional settings are arranged via the menu you find them in. Remember to save your settings with the save button before moving onto a new tab. While still in the Setup -> Basic Setup menu, change the following: Gateway/Local DNS : [IP address of primary router, e.g. 192.168.1.1] NTP Client : Disable The next step is to turn off the radio completely (which not only kills the Wi-Fi but actually powers the physical radio chip off). Navigate to Wireless -> Advanced Settings -> Radio Time Restrictions: Radio Scheduling: Enable Select “Always Off” There’s no need to create a potential security problem by leaving the Wi-Fi radio on, the above toggle turns it completely off. Under Services -> Services: DNSMasq : Disable ttraff Daemon : Disable Under the Security -> Firewall tab, uncheck every box except “Filter Multicast”, as seen in the screenshot above, and then disable SPI Firewall. Once you’re done here save and move on to the Administration tab. Under Administration -> Management:  Info Site Password Protection : Enable Info Site MAC Masking : Disable CRON : Disable 802.1x : Disable Routing : Disable After this final round of tweaks, save and then apply your settings. Your router has now been, strategically, dumbed down enough to plod along as a very dependable little switch. Time to stuff it behind your desk or entertainment center and streamline your cabling.     

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  • TOTD #166: Using NoSQL database in your Java EE 6 Applications on GlassFish - MongoDB for now!

    - by arungupta
    The Java EE 6 platform includes Java Persistence API to work with RDBMS. The JPA specification defines a comprehensive API that includes, but not restricted to, how a database table can be mapped to a POJO and vice versa, provides mechanisms how a PersistenceContext can be injected in a @Stateless bean and then be used for performing different operations on the database table and write typesafe queries. There are several well known advantages of RDBMS but the NoSQL movement has gained traction over past couple of years. The NoSQL databases are not intended to be a replacement for the mainstream RDBMS. As Philosophy of NoSQL explains, NoSQL database was designed for casual use where all the features typically provided by an RDBMS are not required. The name "NoSQL" is more of a category of databases that is more known for what it is not rather than what it is. The basic principles of NoSQL database are: No need to have a pre-defined schema and that makes them a schema-less database. Addition of new properties to existing objects is easy and does not require ALTER TABLE. The unstructured data gives flexibility to change the format of data any time without downtime or reduced service levels. Also there are no joins happening on the server because there is no structure and thus no relation between them. Scalability and performance is more important than the entire set of functionality typically provided by an RDBMS. This set of databases provide eventual consistency and/or transactions restricted to single items but more focus on CRUD. Not be restricted to SQL to access the information stored in the backing database. Designed to scale-out (horizontal) instead of scale-up (vertical). This is important knowing that databases, and everything else as well, is moving into the cloud. RBDMS can scale-out using sharding but requires complex management and not for the faint of heart. Unlike RBDMS which require a separate caching tier, most of the NoSQL databases comes with integrated caching. Designed for less management and simpler data models lead to lower administration as well. There are primarily three types of NoSQL databases: Key-Value stores (e.g. Cassandra and Riak) Document databases (MongoDB or CouchDB) Graph databases (Neo4J) You may think NoSQL is panacea but as I mentioned above they are not meant to replace the mainstream databases and here is why: RDBMS have been around for many years, very stable, and functionally rich. This is something CIOs and CTOs can bet their money on without much worry. There is a reason 98% of Fortune 100 companies run Oracle :-) NoSQL is cutting edge, brings excitement to developers, but enterprises are cautious about them. Commercial databases like Oracle are well supported by the backing enterprises in terms of providing support resources on a global scale. There is a full ecosystem built around these commercial databases providing training, performance tuning, architecture guidance, and everything else. NoSQL is fairly new and typically backed by a single company not able to meet the scale of these big enterprises. NoSQL databases are good for CRUDing operations but business intelligence is extremely important for enterprises to stay competitive. RDBMS provide extensive tooling to generate this data but that was not the original intention of NoSQL databases and is lacking in that area. Generating any meaningful information other than CRUDing require extensive programming. Not suited for complex transactions such as banking systems or other highly transactional applications requiring 2-phase commit. SQL cannot be used with NoSQL databases and writing simple queries can be involving. Enough talking, lets take a look at some code. This blog has published multiple blogs on how to access a RDBMS using JPA in a Java EE 6 application. This Tip Of The Day (TOTD) will show you can use MongoDB (a document-oriented database) with a typical 3-tier Java EE 6 application. Lets get started! The complete source code of this project can be downloaded here. Download MongoDB for your platform from here (1.8.2 as of this writing) and start the server as: arun@ArunUbuntu:~/tools/mongodb-linux-x86_64-1.8.2/bin$./mongod./mongod --help for help and startup optionsSun Jun 26 20:41:11 [initandlisten] MongoDB starting : pid=11210port=27017 dbpath=/data/db/ 64-bit Sun Jun 26 20:41:11 [initandlisten] db version v1.8.2, pdfile version4.5Sun Jun 26 20:41:11 [initandlisten] git version:433bbaa14aaba6860da15bd4de8edf600f56501bSun Jun 26 20:41:11 [initandlisten] build sys info: Linuxbs-linux64.10gen.cc 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 2017:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41Sun Jun 26 20:41:11 [initandlisten] waiting for connections on port 27017Sun Jun 26 20:41:11 [websvr] web admin interface listening on port 28017 The default directory for the database is /data/db and needs to be created as: sudo mkdir -p /data/db/sudo chown `id -u` /data/db You can specify a different directory using "--dbpath" option. Refer to Quickstart for your specific platform. Using NetBeans, create a Java EE 6 project and make sure to enable CDI and add JavaServer Faces framework. Download MongoDB Java Driver (2.6.3 of this writing) and add it to the project library by selecting "Properties", "LIbraries", "Add Library...", creating a new library by specifying the location of the JAR file, and adding the library to the created project. Edit the generated "index.xhtml" such that it looks like: <h1>Add a new movie</h1><h:form> Name: <h:inputText value="#{movie.name}" size="20"/><br/> Year: <h:inputText value="#{movie.year}" size="6"/><br/> Language: <h:inputText value="#{movie.language}" size="20"/><br/> <h:commandButton actionListener="#{movieSessionBean.createMovie}" action="show" title="Add" value="submit"/></h:form> This page has a simple HTML form with three text boxes and a submit button. The text boxes take name, year, and language of a movie and the submit button invokes the "createMovie" method of "movieSessionBean" and then render "show.xhtml". Create "show.xhtml" ("New" -> "Other..." -> "Other" -> "XHTML File") such that it looks like: <head> <title><h1>List of movies</h1></title> </head> <body> <h:form> <h:dataTable value="#{movieSessionBean.movies}" var="m" > <h:column><f:facet name="header">Name</f:facet>#{m.name}</h:column> <h:column><f:facet name="header">Year</f:facet>#{m.year}</h:column> <h:column><f:facet name="header">Language</f:facet>#{m.language}</h:column> </h:dataTable> </h:form> This page shows the name, year, and language of all movies stored in the database so far. The list of movies is returned by "movieSessionBean.movies" property. Now create the "Movie" class such that it looks like: import com.mongodb.BasicDBObject;import com.mongodb.BasicDBObject;import com.mongodb.DBObject;import javax.enterprise.inject.Model;import javax.validation.constraints.Size;/** * @author arun */@Modelpublic class Movie { @Size(min=1, max=20) private String name; @Size(min=1, max=20) private String language; private int year; // getters and setters for "name", "year", "language" public BasicDBObject toDBObject() { BasicDBObject doc = new BasicDBObject(); doc.put("name", name); doc.put("year", year); doc.put("language", language); return doc; } public static Movie fromDBObject(DBObject doc) { Movie m = new Movie(); m.name = (String)doc.get("name"); m.year = (int)doc.get("year"); m.language = (String)doc.get("language"); return m; } @Override public String toString() { return name + ", " + year + ", " + language; }} Other than the usual boilerplate code, the key methods here are "toDBObject" and "fromDBObject". These methods provide a conversion from "Movie" -> "DBObject" and vice versa. The "DBObject" is a MongoDB class that comes as part of the mongo-2.6.3.jar file and which we added to our project earlier.  The complete javadoc for 2.6.3 can be seen here. Notice, this class also uses Bean Validation constraints and will be honored by the JSF layer. Finally, create "MovieSessionBean" stateless EJB with all the business logic such that it looks like: package org.glassfish.samples;import com.mongodb.BasicDBObject;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.DBObject;import com.mongodb.Mongo;import java.net.UnknownHostException;import java.util.ArrayList;import java.util.List;import javax.annotation.PostConstruct;import javax.ejb.Stateless;import javax.inject.Inject;import javax.inject.Named;/** * @author arun */@Stateless@Namedpublic class MovieSessionBean { @Inject Movie movie; DBCollection movieColl; @PostConstruct private void initDB() throws UnknownHostException { Mongo m = new Mongo(); DB db = m.getDB("movieDB"); movieColl = db.getCollection("movies"); if (movieColl == null) { movieColl = db.createCollection("movies", null); } } public void createMovie() { BasicDBObject doc = movie.toDBObject(); movieColl.insert(doc); } public List<Movie> getMovies() { List<Movie> movies = new ArrayList(); DBCursor cur = movieColl.find(); System.out.println("getMovies: Found " + cur.size() + " movie(s)"); for (DBObject dbo : cur.toArray()) { movies.add(Movie.fromDBObject(dbo)); } return movies; }} The database is initialized in @PostConstruct. Instead of a working with a database table, NoSQL databases work with a schema-less document. The "Movie" class is the document in our case and stored in the collection "movies". The collection allows us to perform query functions on all movies. The "getMovies" method invokes "find" method on the collection which is equivalent to the SQL query "select * from movies" and then returns a List<Movie>. Also notice that there is no "persistence.xml" in the project. Right-click and run the project to see the output as: Enter some values in the text box and click on enter to see the result as: If you reached here then you've successfully used MongoDB in your Java EE 6 application, congratulations! Some food for thought and further play ... SQL to MongoDB mapping shows mapping between traditional SQL -> Mongo query language. Tutorial shows fun things you can do with MongoDB. Try the interactive online shell  The cookbook provides common ways of using MongoDB In terms of this project, here are some tasks that can be tried: Encapsulate database management in a JPA persistence provider. Is it even worth it because the capabilities are going to be very different ? MongoDB uses "BSonObject" class for JSON representation, add @XmlRootElement on a POJO and how a compatible JSON representation can be generated. This will make the fromXXX and toXXX methods redundant.

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  • TOTD #166: Using NoSQL database in your Java EE 6 Applications on GlassFish - MongoDB for now!

    - by arungupta
    The Java EE 6 platform includes Java Persistence API to work with RDBMS. The JPA specification defines a comprehensive API that includes, but not restricted to, how a database table can be mapped to a POJO and vice versa, provides mechanisms how a PersistenceContext can be injected in a @Stateless bean and then be used for performing different operations on the database table and write typesafe queries. There are several well known advantages of RDBMS but the NoSQL movement has gained traction over past couple of years. The NoSQL databases are not intended to be a replacement for the mainstream RDBMS. As Philosophy of NoSQL explains, NoSQL database was designed for casual use where all the features typically provided by an RDBMS are not required. The name "NoSQL" is more of a category of databases that is more known for what it is not rather than what it is. The basic principles of NoSQL database are: No need to have a pre-defined schema and that makes them a schema-less database. Addition of new properties to existing objects is easy and does not require ALTER TABLE. The unstructured data gives flexibility to change the format of data any time without downtime or reduced service levels. Also there are no joins happening on the server because there is no structure and thus no relation between them. Scalability and performance is more important than the entire set of functionality typically provided by an RDBMS. This set of databases provide eventual consistency and/or transactions restricted to single items but more focus on CRUD. Not be restricted to SQL to access the information stored in the backing database. Designed to scale-out (horizontal) instead of scale-up (vertical). This is important knowing that databases, and everything else as well, is moving into the cloud. RBDMS can scale-out using sharding but requires complex management and not for the faint of heart. Unlike RBDMS which require a separate caching tier, most of the NoSQL databases comes with integrated caching. Designed for less management and simpler data models lead to lower administration as well. There are primarily three types of NoSQL databases: Key-Value stores (e.g. Cassandra and Riak) Document databases (MongoDB or CouchDB) Graph databases (Neo4J) You may think NoSQL is panacea but as I mentioned above they are not meant to replace the mainstream databases and here is why: RDBMS have been around for many years, very stable, and functionally rich. This is something CIOs and CTOs can bet their money on without much worry. There is a reason 98% of Fortune 100 companies run Oracle :-) NoSQL is cutting edge, brings excitement to developers, but enterprises are cautious about them. Commercial databases like Oracle are well supported by the backing enterprises in terms of providing support resources on a global scale. There is a full ecosystem built around these commercial databases providing training, performance tuning, architecture guidance, and everything else. NoSQL is fairly new and typically backed by a single company not able to meet the scale of these big enterprises. NoSQL databases are good for CRUDing operations but business intelligence is extremely important for enterprises to stay competitive. RDBMS provide extensive tooling to generate this data but that was not the original intention of NoSQL databases and is lacking in that area. Generating any meaningful information other than CRUDing require extensive programming. Not suited for complex transactions such as banking systems or other highly transactional applications requiring 2-phase commit. SQL cannot be used with NoSQL databases and writing simple queries can be involving. Enough talking, lets take a look at some code. This blog has published multiple blogs on how to access a RDBMS using JPA in a Java EE 6 application. This Tip Of The Day (TOTD) will show you can use MongoDB (a document-oriented database) with a typical 3-tier Java EE 6 application. Lets get started! The complete source code of this project can be downloaded here. Download MongoDB for your platform from here (1.8.2 as of this writing) and start the server as: arun@ArunUbuntu:~/tools/mongodb-linux-x86_64-1.8.2/bin$./mongod./mongod --help for help and startup optionsSun Jun 26 20:41:11 [initandlisten] MongoDB starting : pid=11210port=27017 dbpath=/data/db/ 64-bit Sun Jun 26 20:41:11 [initandlisten] db version v1.8.2, pdfile version4.5Sun Jun 26 20:41:11 [initandlisten] git version:433bbaa14aaba6860da15bd4de8edf600f56501bSun Jun 26 20:41:11 [initandlisten] build sys info: Linuxbs-linux64.10gen.cc 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 2017:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41Sun Jun 26 20:41:11 [initandlisten] waiting for connections on port 27017Sun Jun 26 20:41:11 [websvr] web admin interface listening on port 28017 The default directory for the database is /data/db and needs to be created as: sudo mkdir -p /data/db/sudo chown `id -u` /data/db You can specify a different directory using "--dbpath" option. Refer to Quickstart for your specific platform. Using NetBeans, create a Java EE 6 project and make sure to enable CDI and add JavaServer Faces framework. Download MongoDB Java Driver (2.6.3 of this writing) and add it to the project library by selecting "Properties", "LIbraries", "Add Library...", creating a new library by specifying the location of the JAR file, and adding the library to the created project. Edit the generated "index.xhtml" such that it looks like: <h1>Add a new movie</h1><h:form> Name: <h:inputText value="#{movie.name}" size="20"/><br/> Year: <h:inputText value="#{movie.year}" size="6"/><br/> Language: <h:inputText value="#{movie.language}" size="20"/><br/> <h:commandButton actionListener="#{movieSessionBean.createMovie}" action="show" title="Add" value="submit"/></h:form> This page has a simple HTML form with three text boxes and a submit button. The text boxes take name, year, and language of a movie and the submit button invokes the "createMovie" method of "movieSessionBean" and then render "show.xhtml". Create "show.xhtml" ("New" -> "Other..." -> "Other" -> "XHTML File") such that it looks like: <head> <title><h1>List of movies</h1></title> </head> <body> <h:form> <h:dataTable value="#{movieSessionBean.movies}" var="m" > <h:column><f:facet name="header">Name</f:facet>#{m.name}</h:column> <h:column><f:facet name="header">Year</f:facet>#{m.year}</h:column> <h:column><f:facet name="header">Language</f:facet>#{m.language}</h:column> </h:dataTable> </h:form> This page shows the name, year, and language of all movies stored in the database so far. The list of movies is returned by "movieSessionBean.movies" property. Now create the "Movie" class such that it looks like: import com.mongodb.BasicDBObject;import com.mongodb.BasicDBObject;import com.mongodb.DBObject;import javax.enterprise.inject.Model;import javax.validation.constraints.Size;/** * @author arun */@Modelpublic class Movie { @Size(min=1, max=20) private String name; @Size(min=1, max=20) private String language; private int year; // getters and setters for "name", "year", "language" public BasicDBObject toDBObject() { BasicDBObject doc = new BasicDBObject(); doc.put("name", name); doc.put("year", year); doc.put("language", language); return doc; } public static Movie fromDBObject(DBObject doc) { Movie m = new Movie(); m.name = (String)doc.get("name"); m.year = (int)doc.get("year"); m.language = (String)doc.get("language"); return m; } @Override public String toString() { return name + ", " + year + ", " + language; }} Other than the usual boilerplate code, the key methods here are "toDBObject" and "fromDBObject". These methods provide a conversion from "Movie" -> "DBObject" and vice versa. The "DBObject" is a MongoDB class that comes as part of the mongo-2.6.3.jar file and which we added to our project earlier.  The complete javadoc for 2.6.3 can be seen here. Notice, this class also uses Bean Validation constraints and will be honored by the JSF layer. Finally, create "MovieSessionBean" stateless EJB with all the business logic such that it looks like: package org.glassfish.samples;import com.mongodb.BasicDBObject;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.DBObject;import com.mongodb.Mongo;import java.net.UnknownHostException;import java.util.ArrayList;import java.util.List;import javax.annotation.PostConstruct;import javax.ejb.Stateless;import javax.inject.Inject;import javax.inject.Named;/** * @author arun */@Stateless@Namedpublic class MovieSessionBean { @Inject Movie movie; DBCollection movieColl; @PostConstruct private void initDB() throws UnknownHostException { Mongo m = new Mongo(); DB db = m.getDB("movieDB"); movieColl = db.getCollection("movies"); if (movieColl == null) { movieColl = db.createCollection("movies", null); } } public void createMovie() { BasicDBObject doc = movie.toDBObject(); movieColl.insert(doc); } public List<Movie> getMovies() { List<Movie> movies = new ArrayList(); DBCursor cur = movieColl.find(); System.out.println("getMovies: Found " + cur.size() + " movie(s)"); for (DBObject dbo : cur.toArray()) { movies.add(Movie.fromDBObject(dbo)); } return movies; }} The database is initialized in @PostConstruct. Instead of a working with a database table, NoSQL databases work with a schema-less document. The "Movie" class is the document in our case and stored in the collection "movies". The collection allows us to perform query functions on all movies. The "getMovies" method invokes "find" method on the collection which is equivalent to the SQL query "select * from movies" and then returns a List<Movie>. Also notice that there is no "persistence.xml" in the project. Right-click and run the project to see the output as: Enter some values in the text box and click on enter to see the result as: If you reached here then you've successfully used MongoDB in your Java EE 6 application, congratulations! Some food for thought and further play ... SQL to MongoDB mapping shows mapping between traditional SQL -> Mongo query language. Tutorial shows fun things you can do with MongoDB. Try the interactive online shell  The cookbook provides common ways of using MongoDB In terms of this project, here are some tasks that can be tried: Encapsulate database management in a JPA persistence provider. Is it even worth it because the capabilities are going to be very different ? MongoDB uses "BSonObject" class for JSON representation, add @XmlRootElement on a POJO and how a compatible JSON representation can be generated. This will make the fromXXX and toXXX methods redundant.

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  • Building services with .Net Part 1

    - by Allan Rwakatungu
    On the 26th of May 2010 , I made a presentation to the .NET user group meeting (thanks to Malisa Ncube for organizing this event every month … ). If you missed my presentation , we talked about why we should all be building services … better still using the .NET framework. This blog post is an introduction to services , why you would want to build services and how you can build services using the .NET framework. What is a service? OASIS defines service as "a mechanism to enable access to one or more capabilities, where the access is provided using a prescribed interface and is exercised consistent with constraints and policies as specified by the service description." [1]. If the above definition sounds to academic , you can also define a service as loosely coupled units of functionality that have no calls to each other embedded in the. Instead of services embedding calls to each other in their service code they use defined protocols that describe how services pass and parse messages. This is a good way to think about services if you’re from an objected oriented background. While in object oriented programming functions make calls to each other, in service oriented programming, functions pass messages between each other. Why would you want to use services? 1. If your enterprise architecture looks like this   Services are the building blocks for SOA . With SOA you can move away from the sphaggetti infrastructure that is common in most enterprises. The complexity or lack of visibility of the integration points in your enterprises makes it difficult and costly to implement new initiatives and changes into the business - and even impossible in some cases - as it is not possible to identify the impact a change in one system might have to other systems. With services you can move to an architecture like this Your building blocks from Spaghetti infrastructure to something that is more well-defined and manageable to achieve cost efficiency and not least business agility - enabling you to react to changes in the market with speed and achieve operational efficiency and control are services. 2. If you want to become the Gates or Zuckerburger. Have you heard about Web 2.0 ? Mashups? Software as a service (SAAS) ? Cloud computing ?   They all offer you the opportunity to have scalable but low cost business models and they built using services.  Some of my favorite companies that leverage services for their business models include  https://www.salesforce.com/ (cloud CRM) http://www. twitter.com (more people use twitter clients built by 3rd parties than their official clients) http://www.kayak.com/ (compares data from other travel sites to give information to users in one location) Services with the .NET framework      If you are a .NET developer and you want to develop services, Windows Communication Framework (WCF) is the tool for you. WCF is Microsoft’s unified programming model (service model) for building service oriented applications. ( Before .NET 3.0 you had several models for programming services in .NET including .NET remoting, Web services (ASMX), COM +, Microsoft Messaging queuing (MSMQ) etc, after .NET 3.0 the programming model was unified into one i.e. WCF ). Windows Communication Framework (WCF) provides you 1. An Software Development Kit (SDK) for creating SOA applications 2. A runtime for running services on the Windows platform Why should you use Windows Communication Foundation if you’re programming services?   1. It supports interoperable and open standards e.g. WS* protocols for programming SOAP services 2. It has a unified programming model. Whether you use TCP or Http or Pipes or transmitting using Messaging Queues, programmers need to learn just one way to program. Previously you had .NET remoting, MSMQ, Web services, COM+ and they were all done differently 3. Productive programming model You don’t have to worry about all the plumbing involved to write services. You have a rich declarative programming model to add stuff like logging, transactions, and reliable messages in-built in the Windows Communication Framework. Understanding services in WCF The basic principles of WCF are as easy as ABC A – Address This is where the service is located B- Binding This describes how you communicate with the service e.g. Use TCP, HTTP or both. How to exchange security information with the service etc. C – Contract This defines what the service can do. E.g. Pay water bill, Make a phone call A - Addresses In WCF, an address is a combination of transport, server name, port and path Example addresses may include http://localhost:8001 net.tcp://localhost:8002/MyService net.pipe://localhost/MyPipe net.msmq://localhost/private/MyService net.msmq://localhost/MyService B- Binding   There are numerous ways to communicate with services , different ways that a message can be formatted/sent/secured, that allows you to tailor your service for the compatibility/performance you require for your solution. Transport You can use HTTP TCP MSMQ , Named pipes, Your own custom transport etc Message You  can send a plain text binary, Message Transmission Optimization Mechanism (MTOM) message Communication security No security Transport security Message security Authenticating and authorizing callers etc Behaviour You service can support Transactions Be reliable Use queues Support ajax etc C - Contract You define what your service can do using Service contracts :- Define operations that your service can do, communications and behaviours Data contracts :- Define the messages that are passed from and into your service and how they are formatted Fault contracts :- Defines errors types in your service   As an example, suppose your service service shows money. You define your service contract using a interface [ServiceContract] public interface IShowMeTheMoney {   [OperationContract]    Money Show(); } You define the data contract by annotating a class it with the Data Contract attribute and fields you want to pass in the message as Data Members. (Note:- In the latest versions of WCF you dont have to use attributes if you passing all the objects properties in the message) [DataContract] public Money {   [DataMember]   public string Currency { get; set; }   [DataMember]   public Decimal Amount { get; set; }   public string Comment { get; set; } } Features of Windows Communication Foundation Windows Communication Foundation is not only simple but feature rich , offering you several options to tweak your service to fit your business requirements. Some of the features of WCF include 1. Workflow services You can combine WCF with Windows WorkFlow Foundation (WWF) to write workflow type services 2. Control how your data (messages) are transferred and serialized e.g. you can serialize your business objects as XML or binary 3. control over session management , instance creation and concurrency management without writing code if you like 4. Queues and reliable sessions. You can store messages from the sending client and later forward them to the receiving application. You can also guarantee that messages will arrive at their destincation. 5.Transactions:  You can have different services participate in a transaction operations that can be rolled back if needed 6. Security. WCF has rich features for authorization and authentication  as well as keep audit trails 7. Web programming model. WCF allows developers to expose services as non SOAP endpoints 8. Inbuilt features that you can use to write JSON and services that support AJAX applications And lots more In my next blog I will show you how you can use WCF features to write a real world business service.               Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 ]] /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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  • Ada and 'The Book'

    - by Phil Factor
    The long friendship between Charles Babbage and Ada Lovelace created one of the most exciting and mysterious of collaborations ever to have resulted in a technological breakthrough. The fireworks that created by the collision of two prodigious mathematical and creative talents resulted in an invention, the Analytical Engine, which went on to change society fundamentally. However, beyond that, we just don't know what the bulk of their collaborative work was about:;  it was done in strictest secrecy. Even the known outcome of their friendship, the first programmable computer, was shrouded in mystery. At the time, nobody, except close friends and family, had any idea of Ada Byron's contribution to the invention of the ‘Engine’, and how to program it. Her great insight was published in August 1843, under the initials AAL, standing for Ada Augusta Lovelace, her title then being the Countess of Lovelace. It was contained in a lengthy ‘note’ to her translation of a publication that remains the best description of Babbage's amazing Analytical Engine. The secret identity of the person behind those enigmatic initials was finally revealed by Prince de Polignac who, seventy years later, wrote to Ada's daughter to seek confirmation that her mother had, indeed, been the author of the brilliant sentences that described so accurately how Babbage's mechanical computer could be programmed with punch-cards. L.F. Menabrea's paper on the Analytical Engine first appeared in the 'Bibliotheque Universelle de Geneve' in October 1842, and Ada translated it anonymously for Taylor's 'Scientific Memoirs'. Charles Babbage was surprised that she had not written an original paper as she already knew a surprising amount about the way the machine worked. He persuaded her to at least write some explanatory notes. These notes ended up extending to four times the length of the original article and represented the first published account of how a machine could be programmed to perform any calculation. Her example of programming the Bernoulli sequence would have worked on the Analytical engine had the device’s construction been completed, and gave Ada an unassailable claim to have invented the art of programming. What was the reason for Ada's secrecy? She was the only legitimate child of Lord Byron, who was probably the best known celebrity of the age, so she was already famous. She was a senior aristocrat, with titles, a fortune in money and vast estates in the Midlands. She had political influence, and was the cousin of Lord Melbourne, who was the Prime Minister at that time. She was friendly with the young Queen Victoria. Her mathematical activities were a pastime, and not one that would be considered by others to be in keeping with her roles and responsibilities. You wouldn't dare to dream up a fictional heroine like Ada. She was dazzlingly beautiful and talented. She could speak several languages fluently, and play some musical instruments with professional skill. Contemporary accounts refer to her being 'accomplished in science, art and literature'. On top of that, she was a brilliant mathematician, a talent inherited from her mother, Annabella Milbanke. In her mother's circle of literary and scientific friends was Charles Babbage, and Ada's friendship with him dates from her teenage zest for Mathematics. She was one of the first people he'd ever met who understood what he had attempted to achieve with the 'Difference Engine', and with whom he could converse as intellectual equals. He arranged for her to have an education from the most talented academics in the country. Ada melted the heart of the cantankerous genius to the point that he became a faithful and loyal father-figure to her. She was one of the very few who could grasp the principles of the later, and very different, ‘Analytical Engine’ which was designed from the start to tackle a variety of tasks. Sadly, Ada Byron's life ended less than a decade after completing the work that assured her long-term fame, in November 1852. She was dying of cancer, her gambling habits had caused her to run up huge debts, she'd had more than one affairs, and she was being blackmailed. Her brilliant but unempathic mother was nursing her in her final illness, destroying her personal letters and records, and repaying her debts. Her husband was distraught but helpless. Charles Babbage, however, maintained his steadfast paternalistic friendship to the end. She appointed her loyal friend to be her executor. For years, she and Babbage had been working together on a secret project, known only as 'The Book'. We have a clue to what it was in a letter written by her nine years earlier, on 11th August 1843. It was a joint project by herself and Lord Lovelace, her husband, and was intended to involve Babbage's 'undivided energies'. It involved 'consulting your Engine' (it required Babbage’s computer). The letter gives no hint about the project except for the high-minded nature of its purpose, and its highly mathematical nature.  From then on, the surviving correspondence between the two gives only veiled references to 'The Book'. There isn't much, since Babbage later destroyed any letters that could have damaged her reputation within the Establishment. 'I cannot spare the book today, which I am very sorry for. At the moment I want it for constant reference, but I think you can have it tomorrow' (Oct 1844)  And 'I will send you the book directly, and you can say, when you receive it, how long you will want to keep it'. (Nov 1844)  The two of them were obviously intent on the work: She writes, four years later, 'I have an engagement for Wednesday which will prevent me from attending to your wishes about the book' (Dec 1848). This was something that they both needed to work on, but could not do in parallel: 'I will send the book on Tuesday, and it can be left with you till Friday' (11 Feb 1849). After six years work, it had been so well-handled that it was beginning to fall apart: 'Don't forget the new cover you promised for the book. The poor book is very shabby and wants one' (20 Sept 1849). So what was going on? The word 'book' was not a code-word: it was a real book, probably a 'printer's blank', plain paper, but properly bound so printers and publishers could show off how the published work might look. The hints from the correspondence are of advanced mathematics. It is obvious that the book was travelling between them, back and forth, each one working on it for less than a week before passing it back. Ada and her husband were certainly involved in gambling large sums of money on the horses, and so most biographers have concluded that the three of them were trying to calculate the mathematical odds on the horses. This theory has three large problems. Firstly, Ada's original letter proposing the project refers to its high-minded nature. Babbage was temperamentally opposed to gambling and would scarcely have given so much time to the project, even though he was devoted to Ada. Secondly, Babbage would have very soon have realized the hopelessness of trying to beat the bookies. This sort of betting never attracts his type of intellectual background. The third problem is that any work on calculating the odds on horses would not need a well-thumbed book to pass back and forth between them; they would have not had to work in series. The original project was instigated by Ada, along with her husband, William King-Noel, 1st Earl of Lovelace. Charles Babbage was invited to join the project after the couple had come up with the idea. What could William have contributed? One might assume that William was a Bertie Wooster character, addicted only to the joys of the turf, but this was far from the truth. He was a scientist, a Cambridge graduate who was later elected to be a Fellow of the Royal Society. After Eton, he went to Trinity College, Cambridge. On graduation, he entered the diplomatic service and acted as secretary under Lord Nugent, who was Lord Commissioner of the Ionian Islands. William was very friendly with Babbage too, able to discuss scientific matters on equal terms. He was a capable engineer who invented a process for bending large timbers by the application of steam heat. He delivered a paper to the Institution of Civil Engineers in 1849, and received praise from the great engineer, Isambard Kingdom Brunel. As well as being Lord Lieutenant of the County of Surrey for most of Victoria's reign, he had time for a string of scientific and engineering achievements. Whatever the project was, it is unlikely that William was a junior partner. After Ada's death, the project disappeared. Then, two years later, Babbage, through one of his occasional outbursts of temper, demonstrated that he was able to decrypt one of the most powerful of secret codes, Vigenère's autokey cipher.  All contemporary diplomatic and military messages used a variant of this cipher. Babbage had made three important discoveries, namely, the mathematical law of this cipher, the principle of the key periodicity, and the technique of the symmetry of position. The technique is now known as the Kasiski examination, also called the Kasiski test, but Babbage got there first. At one time, he listed amongst his future projects, the writing of a book 'The Philosophy of Decyphering', but it never came to anything. This discovery was going to change the course of history, since it was used to decipher the Russians’ military dispatches in the Crimean war. Babbage himself played a role during the Crimean War as a cryptographical adviser to his friend, Rear-Admiral Sir Francis Beaufort of the Admiralty. This is as much as we can be certain about in trying to make sense of the bulk of the time that Charles Babbage and Ada Lovelace worked together. Nine years of intensive work, involving the 'Engine' and a great deal of mathematics and research seems to have been lost: or has it? I've argued in the past http://www.simple-talk.com/community/blogs/philfactor/archive/2008/06/13/59614.aspx that the cracking of the Vigenère autokey cipher, was a fundamental motive behind the British Government's support and funding of the 'Difference Engine'. The Duke of Wellington, whose understanding of the military significance of being able to read enemy dispatches, was the most steadfast advocate of the project. If the three friends were actually doing the work of cracking codes by mathematical techniques that used the techniques of key periodicity, and symmetry of position (the use of a book being passed quickly to and fro is very suggestive), intending to then use the 'Engine' to do the routine cracking of each dispatch, then this is a rather different story. The project was Ada and William's idea. (William had served in the diplomatic service and would be familiar with the use of codes). This makes Ada Lovelace the initiator of a project which, by giving both Britain, and probably the USA, a diplomatic and military advantage in the second part of the Nineteenth century, changed world history. Ada would never have wanted any credit for cracking the cipher, and developing the method that rendered all contemporary military and diplomatic ciphering techniques nugatory; quite the reverse. And it is clear from the gaps in the record of the letters between the collaborators that the evidence was destroyed, probably on her request by her irascible but intensely honorable executor, Charles Babbage. Charles Babbage toyed with the idea of going public, but the Crimean war put an end to that. The British Government had a valuable secret, and intended to keep it that way. Ada and Charles had quite often discussed possible moneymaking projects that would fund the development of the Analytic Engine, the first programmable computer, but their secret work was never in the running as a potential cash cow. I suspect that the British Government was, even then, working on the concealment of a discovery whose value to the nation depended on it remaining so. The success of code-breaking in the Crimean war, and the American Civil war, led to the British and Americans  subsequently giving much more weight and funding to the science of decryption. Paradoxically, this makes Ada's contribution even closer to the creation of Colossus, the first digital computer, at Bletchley Park, specifically to crack the Nazi’s secret codes.

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  • CodePlex Daily Summary for Wednesday, June 09, 2010

    CodePlex Daily Summary for Wednesday, June 09, 2010New Projects.NET Transactional File Manager: Transactional File Manager is a .NET API that supports including file system operations such as file copy, move, delete in a transaction. It's an i...3D World Studio Content Pipeline for Windows Phone 7: This is a port of PhotonicGames' project: http://xna3dws.codeplex.com/releases/view/42994 for the Windows Phone 7 tools (XNA 4.0 CTP).Advanced Script Editor for 3D Rad: Advanced Script Editor makes it easier for 3D Rad coders to write scripts. Developed in C#, it features a functions list, a favourites list, object...Ajax ASP.Net Forum: A fast & lightweight open source free forum developed in ASP.Net 3.5, AJAX, CSS, SQL & Javascript Cache (filter-sort-move through table records at ...Axon: Axon is the home automation system that I will be running in my home. It will be a collection of different technologies and projects, often experim...BigBallz: Projeto de site de Bolões para campeonatos diversos. A princípio pensado para copa do mundo de futebol de 2010BigfootMVC: MVC Framework for DotNetNukeBigfootSQL: A StringBuilder for SQL. BigfootSQL was built with simplicity in mind. It assumes that you are comfortable writing SQL but dislike effort required ...Bxf (Basic XAML Framework): Basic Xaml Framework (Bxf) is a simple, streamlined set of UI components designed to demonstrate the minimum framework functionality required to ma...elZerf - elektronische Zeiterfassung: elektronisches Zeiterfassungsystem im Rahmen der Seminararbeit im Modul Web-Anwendungsprogrammierung.IntoFactories.Net - Samples: Project to host samples created by members of the IntoFactories.NET Team blog.Lanchonete: Sistema para controle de lanchonetes. Medieval Dynasties: Medieval Dynasties is a game written in C# 3.5 and XNA 3.1 at the moment. It is inspired by Crusader Kings, Total War and Civilization.PMMsg: A project to replace the standard messaging client on the Windows Mobile platform. Mainly geared towards Windows Mobile 6.5.3 VGA devices. Also an...PunkPong: PunkPong is an open source "Pong" alike game totally written in DHTML (JavaScript, CSS and HTML) that uses keyboard or mouse. This cross-platform a...Renegade Legion Fighter Calculator: In working on assigning fighters to squadrons, flights, and groups for a campaign, I was struck by the sheer amount of calculations I had to make. ...Sharpotify - Spotify .Net Library: Sharpotify is a Spotify library in C#. It is based in Jotify and SharPot projects. It is not a libspotify wrapper, It is a full .Net Spotify protoc...Silverlight load on demand with MEF: With MEF, a Silverlight control can be split in several packages(xap files). Each package can contain one or more pages and it will download on dem...SOLID by example: Source code examples to undestood solid design principles. Most of them were taken from http://www.lostechies.com/SQL Server 2008 Reporting Services RS.EXE Supporting Forms Authentication: A version of RS.EXE that you can use with Forms Authentication in Native Mode. Use the following arguments to specify credentials (just like Basic ...Stripper: Stripper Remove Diacritics and other unwanted caracter to fabric a more standardized file naming.study: studyUncoverPIC: UncoverPIC is a Silverlight Game strongly inspired to the famous Arcade Game "GalsPanic" (see http://en.wikipedia.org/wiki/Gals_Panic ). It was dev...Unity3D Untitled MMO: Unity3D Untitled MMO FrameworkUnnamedShop: UnnamedShopXBStudio.asp.net.automation: A Unit Testing Automation library for asp.netXBStudio.Web: XBStudio Web ApplicationNew Releases3D World Studio Content Pipeline for Windows Phone 7: Initial Release (0.1): This is the first release of the project, with plenty of hackery and kludges to go around, but it mostly works! Let me know if you hit any bugs.Acies: Acies - Alpha Build 0.0.10: Alpha release. Requires Microsoft XNA Framework Redistributable 3.1 (http://www.microsoft.com/downloads/details.aspx?FamilyID=53867a2a-e249-4560-...Advanced Script Editor for 3D Rad: Advanced Script Editor - Version 2.6: Despite various previous releases on the 3D Rad forum, this is the first release on CodePlex.Ajax ASP.Net Forum: First Release: First Release prior to CodePlex Publish (send to admins)So, it doesn't all finish VERSION: 0.1.2 FEATURES Main Home Where all the Forums (called ...Artist Follower for Microsoft Access: Artist Follower 0.5.1: Artists Follower changes: Just one form to manage artists and links!!!Artist Follower for Microsoft Access: Artists Follower 0.5.0: This is the first release of Artist Follower.ASP.NET MVC SiteMap provider - MvcSiteMapProvider: MvcSiteMapProvider 2.0.0 CTP1: This is a community technology preview of MvcSiteMapProvider version 2.0. It is not backwards compatible with older MvcSiteMapProvider versions. ...B&W Port Scanner: Black`n`White Port Scanner 4.0: Version 4 includes: - Improved vulnerability detection tools - Report Creation - Improved Stability - Much better port information database - Nume...BaseCalendar: BaseControls 1.1: BaseControls 1.1 contains the BaseCalendar ASP.NET control. Changes: Rendering TH by default inside THEAD. Added option (ShowMinNumWeeks) to r...BigfootSQL: BigfootSQL Source Code: BigfootSQL C# Version 01Commerce Server 2009 Orders using Pipelines in a Console Application: ConsoleApplication To PLace Orders: ConsoleApplication To PLace Orders with Commerce Server 2009 foundationCommunity Forums NNTP bridge: Community Forums NNTP Bridge V33: Release of the Community Forums NNTP Bridge to access the social and anwsers MS forums with a single, open source NNTP bridge. This release has ad...Community Forums NNTP bridge: Community Forums NNTP Bridge V34: Release of the Community Forums NNTP Bridge to access the social and anwsers MS forums with a single, open source NNTP bridge. This release has ad...ContainerOne - C# application server: V0.1.2.0: New minor release containing: Integration test component for runtime testing Refactored and cleaned solution files First unit testsExtend SmallBasic: Teaching Extensions v.020: Moved Tortoise.approve to ProgramWindow.TakeScreenShot()fleet It: v0.06 Alpha: v0.06 Alpha - Features Caching implemented for fleets Various Bug fixes Implemented Settings. Resolved logical issue with Getting fleets U...Frotz.NET: Frotz.NET B2: In addition to B1 changes: - Added ZTools to enable debugging view of zcode files - Added rudimentary scroll back buffer. B1 Changes: - Got Adapt...FsObserver: FsObserver 2.0: This is basically the same as FsObserver 1.0 but the "-help" documentation has been cleaned up somewhat and the code has been refactored so that it...GPdotNET - Genetic Programming Tool: GPdotNETv1.0: GPdotNET v.1.0 - more details on http.bhrnjica.wordpress.com/gpdotnetHERB.IQ: Alpha 0.1 Source code release 8: Alpha 0.1 Source code release 8imdb movie downloader: myImdb 0.9.3: myImdb 0.9.3imdb movie downloader: myImdb 0.9.4: myImdb 0.9.4jccc .NET smart framework: jccc .NET smart framework version 1.2010.06.07: jccc .NET smart framework version 1.2010.06.07 added oracle databases supportLongBar: LongBar 2.1 Build 313: - Fixed library and updates to work with updated live services - Options: You can disable shadow nowMDownloader: MDownloader-0.15.17.59623: Fixed FileFactory provider. Improvied postpone policies. Added network request limiter.MediaCoder.NET: MediaCoder.NET v1.0 beta 1.1: Installer for MediaCoder.NET v1.0 beta1.1. It can now convert files with spaces in the path or filename. I have also created filter for the SaveFil...MediaCoder.NET: MediaCoder.NET v1.0 beta 1.1 Source Code: Source Code for MediaCoder.NET v1.0 beta 1.1.mesoBoard: mesoBoard - 0.9.1 beta: Fixed file download permissions Released under the New BSD License.MPCLI: Alpha Release (0.1.0.0): This release has core functionality and is considered a potential candidate for a feature complete release of this library. However, suggestions fo...N2 CMS: 2.0: N2 is a lightweight CMS framework for ASP.NET. It helps professional developers build great web sites that anyone can update. Major Changes (1.5 -...NHTrace: NHTrace-47571: NHTrace-47571NodeXL: Network Overview, Discovery and Exploration for Excel: NodeXL Class Libraries, version 1.0.1.125: The NodeXL class libraries can be used to display network graphs in .NET applications. To include a NodeXL network graph in a WPF desktop or Windo...NSoup: NSoup 0.2: NSoup 0.2 corresponds to jsoup version 1.1.1. List of changes can be viewed here.Opalis Community Releases: Integration Pack for Data Manipulation: The Integration Pack for Data Manipulation enables you to perform a wider variety of data manipulation tasks as well as aggregate data into common ...Performance Analysis of Logs (PAL) Tool: PAL v2.0 Beta 1: Fixed Counter Sorting: Fixed a minor bug where duplicate counter expression paths were not being removed. Analysis Added: Added LogicalDisk Read/...RoTwee: RoTwee (12.0.0.0): Trial version. 17925 Make it possible to change window sizeSharpotify - Spotify .Net Library: Sharpotify.Library 1.0: Sharpotify Library: Stable release. 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I release this as a .zip archive, because settings are added here, so there will be .exe and .config files.Yet Another GPS: Alfa Release: Alfa working releaseMost Popular ProjectsDozer Enterprise Library for .NETEmployee Management SystemWiiMote PhysicsVisualStudio 2010 JavaScript OutliningSpider CompilerConcurrent CacheOil Slick Live FeedsCSUFVGDC Summer JamWinGetSiteMap Utility for DNN Blog ModuleMost Active ProjectsCommunity Forums NNTP bridgepatterns & practices – Enterprise LibraryRhyduino - Arduino and Managed CodejQuery Library for SharePoint Web ServicesRawrNB_Store - Free DotNetNuke Ecommerce Catalog ModuleAndrew's XNA HelpersBlogEngine.NETStyleCopCustomer Portal Accelerator for Microsoft Dynamics CRM

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