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• I can't program because the code I am using uses old coding styles. Is this normal to programmers? [closed]

  - by Renato Dinhani Conceição

  I'm in my first real job as programmer, but I can't solve any problems because of the coding style used. The code here: Does not have comments Does not have functions (50, 100, 200, 300 or more lines executed in sequence) Uses a lot of if statements with a lot of paths Has variables that make no sense (eg.: cf_cfop, CF_Natop, lnom, r_procod) Uses an old language (Visual FoxPro 8 from 2002), but there are new releases from 2007. I feel like I have gone back to 1970. Is it normal for a programmer familiar with OOP, clean-code, design patterns, etc. to have trouble with coding in this old-fashion way? EDIT: All the answers are very good. For my (un)hope, appears that there are a lot of this kind of code bases around the world. A point mentioned to all answers is refactor the code. Yeah, I really like to do it. In my personal project, I always do this, but... I can't refactor the code. Programmers are only allowed to change the files in the task that they are designed for. Every change in old code must be keep commented in the code (even with Subversion as version control), plus meta informations (date, programmer, task) related to that change (this became a mess, there are code with 3 used lines and 50 old lines commented). I'm thinking that is not only a code problem, but a management of software development problem.

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• TCO Models: Oracle invites you to the next webcast dedicated to Partners on Oracle Hardware and Solutions

  - by mseika

  The Oracle Hardware and Solutions Webcast Series is a sequence of one-hour Sales-Oriented Web Seminars, dedicated to Oracle Partners. This is your opportunity to learn about Oracle's Servers, Storage and Solutions strategy and portfolio, and their business value for you and your customers. The next appointment is for Wednesday, June 22, at 9am UKT / 10am CET:Total Cost of Ownership Models Examples: How we can sell Oracle HW and SW together, with better TCO, and benefits for both Oracle and the Partner!with Ilkka Vanhanen, Business Development Manager, Oracle EMEA Hardware Strategy Organization, who will talk about:   Concrete examples of the HW/SW TCO Model   Understand the competitive advantage provided by Oracle-on-Oracle Solutions   How Partners get new business from Oracle-on-Oracle Solutions   How Oracle is changing the game in Enterprise IT   Key benefits for both SW Resellers and HW Resellers   To register click here , then click on the “Servers and Solutions Webcasts” tab.          

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• How to model the components of a non Information System?

  - by Adel C Kod

  So I am working on a project that's related to the Kernel code(specifically related to the TCP/IP stack of the kernel). I need to build some models to describe the functionality and components of my system. Initially I thought about Class Diagram, it can describe the general architecture of my system but it doesn't make sense since my code is VERY structured(written in standard C). I also thought about DFDs, they'd describe the processes of my system, and how the data is flowing. But they contain something which doesn't really fit in; data-storages. I have no databases here(at all). For the functionality, other team members suggested using Activity and Sequence diagrams, which is kinda okay with me, but what about the system components? So basically my question is; I want to describe the components of my system; what do you suggest as a meaningful diagram to follow? (Again, the project is a research low-level systems-oriented project with almost no user-interface at all)

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• Computer suddenly won't boot - stops at a flashing prompt

  - by Dave M G

  I have been running Ubuntu on my computer for a long time, and I have been using 11.10 since it became available in October. Suddenly, this morning, when I rebooted, the computer would not reach the log in screen. I go through the standard POST boot sequence, and I also get a splash screen for my Nvidia graphics card, so at least most of the hardware seems to be working. After that, all I get is a flashing text prompt - one blinking white underline character on a screen that is otherwise completely blank. I don't think it is even reaching GRUB. No key input is possible. I have tried various key combinations to try and initiate some kind of interface, be it command line or anything else. The only key combination that works is [CTRL]+[ALT]+[Delete] to reboot. I realize this is likely to be a hardware problem, but it could be an Ubuntu problem(?), so I'm hoping for a specific set of troubleshooting steps so I can diagnose and repair this issue. My current suspicion is that one of the drives in my 2 disk software RAID has failed (even though they should be too new for that). However, this computer is critical to my work, so I'd like to invite advice on any possibilities so as to waste as little time as possible in fixing this machine.

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• Oracle E-Business Products New Search Helpers for Guided Resolution of Customer Issues

  - by user793044

  Oracle E-Business Proactive Support has created many new guided resolution documents that you may find helpful in resolving issues in your EBS applications.  These new documents are called “Search Helpers” and they guide you through your issue to a solution.  They are meant to be an easy and fast method to finding a relevant, complete solution. Hundreds of notes and service requests were reviewed and the best solutions to these known issues were selected.  For some issues, notes were updated to better clarify the solution.  In other cases, if a note with a solution did not already exist, one was created. You start the process by selecting the scenario you have encountered.  You may have received an error message, or there may be a particular area of the application in which you have encountered an issue.  Based on your selection of the issue, the Search Helper will present one or more additional possible symptoms.  When you have selected from both of these two sections, you are then presented with one or more articles known to have fully solved this issue in the past.  Several EBS products have produced Search Helpers documents.  Take a look at Doc ID 1501724.1 for an index of the current EBS Search Helpers.  Here is an example of a Search Helper from the Receivables Transactions area: After selecting the Functional Area of "Entering / Updating Transactions" a list of Known Symptoms is presented: And, when "Transaction numbers are not in sequence" is selected, a solution link is provided for Document ID 197212.1: How To Setup Gapless Document Sequencing in Receivables. The EBS applications that currently have published Search Helpers are: Advanced Pricing Applications Technology Configurator General Ledger Human Capital Management Inventory Management Order Management Payables Process Manufacturing Purchasing Receivables Shipping Value Chain Planning

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• F# Application Entry Point

  - by MarkPearl

  Up to now I have been looking at F# for modular solutions, but have never considered writing an end to end application. Today I was wondering how one would even start to write an end to end application and realized that I didn’t even know where the entry point is for an F# application. After browsing MSDN a bit I got a basic example of a F# application with an entry point [<EntryPoint>] let main args = printfn "Arguments passed to function : %A" args // Return 0. This indicates success. 0 Pretty simple stuff… but what happens when you have a few modules in a program – so I created a F# project with two modules and a main module as illustrated in the image below… When I try to compile my program I get a build error… A function labeled with the 'EntryPointAttribute' attribute must be the last declaration in the last file in the compilation sequence, and can only be used when compiling to a .exe… What does this mean? After some more reading I discovered that the Program.fs needs to be the last file in the F# application – the order of the files in a F# solution are important. How do I move a source file up or down? I tried dragging the Program.fs file below ModuleB.fs but it wouldn’t allow me to. Then I thought to right click on a source file and got the following menu.   Wala… to move the source file to the bottom of the solution you can select the “Move Up” or “Move Down” option. Now that I got this right I decided to put some code in ModuleA & ModuleB and I have the start of a basic application structure. ModuleA Code namespace MyApp module ModuleA = let PrintModuleA = printf "hello a \n" ()   ModuleB Code namespace MyApp module ModuleB = let PrintModuleB = printf "hello b \n" ()   Program Code // Learn more about F# at http://fsharp.net #light namespace MyApp module Main = open System [<EntryPoint>] let main args = ModuleA.PrintModuleA let endofapp = Console.ReadKey() 0

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• Tail-recursive implementation of take-while

  - by Giorgio

  I am trying to write a tail-recursive implementation of the function take-while in Scheme (but this exercise can be done in another language as well). My first attempt was (define (take-while p xs) (if (or (null? xs) (not (p (car xs)))) '() (cons (car xs) (take-while p (cdr xs))))) which works correctly but is not tail-recursive. My next attempt was (define (take-while-tr p xs) (let loop ((acc '()) (ys xs)) (if (or (null? ys) (not (p (car ys)))) (reverse acc) (loop (cons (car ys) acc) (cdr ys))))) which is tail recursive but needs a call to reverse as a last step in order to return the result list in the proper order. I cannot come up with a solution that is tail-recursive, does not use reverse, only uses lists as data structure (using a functional data structure like a Haskell's sequence which allows to append elements is not an option), has complexity linear in the size of the prefix, or at least does not have quadratic complexity (thanks to delnan for pointing this out). Is there an alternative solution satisfying all the properties above? My intuition tells me that it is impossible to accumulate the prefix of a list in a tail-recursive fashion while maintaining the original order between the elements (i.e. without the need of using reverse to adjust the result) but I am not able to prove this. Note The solution using reverse satisfies conditions 1, 3, 4.

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• How do I produce "enjoyably" random, as opposed to pseudo-random?

  - by Hilton Campbell

  I'm making a game which presents a number of different kinds of puzzles in sequence. I choose each puzzle with a pseudorandom number. For each puzzle, there are a number of variations. I choose the variation with another pseudorandom number. And so on. The thing is, while this produces near-true randomness, this isn't what the player really wants. The player typically wants what they perceive to be and identify as random, but only if it doesn't tend to repeat puzzles. So, not really random. Just unpredictable. Giving it some thought, I can imagine hacky ways of doing it. For example, temporarily eliminating the most recent N choices from the set of possibilities when selecting a new choice. Or assigning every choice an equal probability, reducing a choice's probability to zero on selection, and then increasing all probabilities slowly with each selection. I assume there's an established way of doing this, but I just don't know the terminology so I can't find it. Anyone know? Or has anyone solved this in a pleasing way?

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• Is there a formula for this?

  - by Gortron

  TL/DR: Any way to work out if known numbers between a known start and ending figure should be positive or negative numbers? I am developing an application in PHP which can import and read PDFs. The PDFs are financial ones such as bank statements with records of transactions in and out of a bank account. I only have PDFs to work with, no other formats such as CSV unfortunately. I convert the PDF to HTML using pdftohtml and start parsing the data, the intended end result is an array of transactions. So far I have it working smoothly collecting dates, descriptions and balance. Converting the XML instead doesn't help. There are other pieces of transcriptional data such as debit or credit amounts. In the PDF, the credit amount is in one column and the debit amount is in another column so it is quite clear in the PDF. However, when converted to HTML, the formatting is lost and therefor I don't know if the amount was a credit or debit amount. So, my question is, given a starting balance and an ending balance and several known figures in between, is it possible for a programme to work out if those known figures in between are credit or debit amounts? I imagine there could potentially be several combinations of those known values to reach the ending balance so I'd like to apply a formula to return the correct credit/debit sequence only if its the only possible solution. If there are several ways of adding/subtracting the known values to reach the end balance, I can ask the user to look at it manually but I'd like to keep this to a minimum if possible. Possible to do, do you think? Thank you in advance for any help.

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• Why is MediaWiki auto-linking the word “files”

  - by dfrankow

  Our MediaWiki installation is auto-linking the word "files". So Here are some files: a, b, c would result in the word "files" being linked to http://ourhost/mediawiki/files. Why is that happening and how do I make it stop? I can use the nowiki tag, but perhaps it does not surprise you that the word "files" appears often, and it is aggravating to use that tag all the time. Here is some info on our MediaWiki installation from Special:Version. Yes, it's old. Installed software Product Version MediaWiki 1.16.5 PHP 5.2.14-pl0-gentoo (apache2handler) MySQL 5.0.84 Installed extensions Parser hooks GoogleDocs4MW (Version 1.1) Adds tag for Google Docs' spreadsheets display Jack Phoenix SyntaxHighlight (Version 1.0.8.6) Provides syntax highlighting using GeSHi Highlighter Brion Vibber, Tim Starling, Rob Church and Niklas Laxström WebServiceSequenceDiagram(Version 1.0) Render inline sequence diagrams using websequencediagrams.com Eddie Olsson Other MWSearch MWSearch plugin Kate Turner and Brion Vibber Extension functions efLucenePrefixSetup Parser extension tags gallery, googlespreadsheet, html, nowiki, pre, sequencediagram, source and syntaxhighlight Parser function hooks anchorencode, basepagename, basepagenamee, defaultsort, displaytitle, filepath, formatdate, formatnum, fullpagename, fullpagenamee, fullurl, fullurle, gender, grammar, int, language, lc, lcfirst, localurl, localurle, namespace, namespacee, ns, nse, numberingroup, numberofactiveusers, numberofadmins, numberofarticles, numberofedits, numberoffiles, numberofpages, numberofusers, numberofviews, padleft, padright, pagename, pagenamee, pagesincategory, pagesize, plural, protectionlevel, special, subjectpagename, subjectpagenamee, subjectspace, subjectspacee, subpagename, subpagenamee, tag, talkpagename, talkpagenamee, talkspace, talkspacee, uc, ucfirst and urlencode

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• Do you do custom tests/work for a potential employer before the interview?

  - by Chuck Stephanski

  Every shop I've worked at we have followed what I thought was a standard hiring sequence: 1. solicit resumes 2. phone screen applicants we are interested in 3. in person interview 4. in some shops 2nd in person interview (just w/ CEO for example) Most places I apply to follow something along these lines. But some shops want to give me a test or ask me to build something after I send in my resume. They usually say "congratulations, you've made it to stage 2 of our hiring process!" But for all I know they are asking every applicant they get a resume from to do the same thing. This annoys me because it doesn't scale. If I'm applying for a lot of positions I can't spend all my time doing work that potentially can only land me one job. Plus there's no shared dedication to the process. If we do a 45 minute phone screen, that's 45 minutes the company commits to me and 45 minutes I commit to the company in hopes of a potential match. Do you guys have a policy regarding these sorts of things?

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• How to implement isValid correctly?

  - by Songo

  I'm trying to provide a mechanism for validating my object like this: class SomeObject { private $_inputString; private $_errors=array(); public function __construct($inputString) { $this->_inputString = $inputString; } public function getErrors() { return $this->_errors; } public function isValid() { $isValid = preg_match("/Some regular expression here/", $this->_inputString); if($isValid==0){ $this->_errors[]= 'Error was found in the input'; } return $isValid==1; } } Then when I'm testing my code I'm doing it like this: $obj = new SomeObject('an INVALID input string'); $isValid = $obj->isValid(); $errors=$obj->getErrors(); $this->assertFalse($isValid); $this->assertNotEmpty($errors); Now the test passes correctly, but I noticed a design problem here. What if the user called $obj->getErrors() before calling $obj->isValid()? The test will fail because the user has to validate the object first before checking the error resulting from validation. I think this way the user depends on a sequence of action to work properly which I think is a bad thing because it exposes the internal behaviour of the class. How do I solve this problem? Should I tell the user explicitly to validate first? Where do I mention that? Should I change the way I validate? Is there a better solution for this? UPDATE: I'm still developing the class so changes are easy and renaming functions and refactoring them is possible.

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• Should I always encapsulate an internal data structure entirely?

  - by Prog

  Please consider this class: class ClassA{ private Thing[] things; // stores data // stuff omitted public Thing[] getThings(){ return things; } } This class exposes the array it uses to store data, to any client code interested. I did this in an app I'm working on. I had a ChordProgression class that stores a sequence of Chords (and does some other things). It had a Chord[] getChords() method that returned the array of chords. When the data structure had to change (from an array to an ArrayList), all client code broke. This made me think - maybe the following approach is better: class ClassA{ private Thing[] things; // stores data // stuff omitted public Thing[] getThing(int index){ return things[index]; } public int getDataSize(){ return things.length; } public void setThing(int index, Thing thing){ things[index] = thing; } } Instead of exposing the data structure itself, all of the operations offered by the data structure are now offered directly by the class enclosing it, using public methods that delegate to the data structure. When the data structure changes, only these methods have to change - but after they do, all client code still works. Note that collections more complex than arrays might require the enclosing class to implement even more than three methods just to access the internal data structure. Is this approach common? What do you think of this? What downsides does it have other? Is it reasonable to have the enclosing class implement at least three public methods just to delegate to the inner data structure?

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• Is it OK to create all primary partitions.?

  - by james

  I have a 320GB hard disk. I only use either ubuntu or kubuntu (12.04 for now). I don't want to use windows or any other dual boot os. And i need only 3 partitions on my hard disk. One for the OS and remaining two for data storage. I don't want to create swap also. Now can i create all primary partitions on the hard disk. Are there any disadvantages in doing so. If all the partitions are primary i think i can easily resize partitions in future. On second thought i have the idea of using seperate partition for /home. Is it good practice . If i have to do this, i will create 4 partitions all primary. In any case i don't want to create more than 4 partitions . And i know the limit will be 4. So is it safe to create all 3 or 4 primary partitions. Pls suggest me, What are the good practices . (previously i used win-xp and win-7 on dual boot with 2 primary partitions and that bugged me somehow i don't remember. Since then i felt there should be only one primary partition in a hard disk.) EDIT 1 : Now i will use four partitions in the sequence - / , /home , /for-data , /swap . I have another question. Does a partition need continuous blocks on the disk. I mean if i want to resize partitions later, can i add space from sda3 to sda1. Is it possible and is it safe to do ?

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• OpenGL : sluggish performance in extracting texture from GPU

  - by Cyan

  I'm currently working on an algorithm which creates a texture within a render buffer. The operations are pretty complex, but for the GPU this is a simple task, done very quickly. The problem is that, after creating the texture, i would like to save it. This requires to extract it from GPU memory. For this operation, i'm using glGetTexImage(). It works, but the performance is sluggish. No, i mean even slower than that. For example, an 8MB texture (uncompressed) requires 3 seconds (yes, seconds) to be extracted. That's mind puzzling. I'm almost wondering if my graphic card is connected by a serial link... Well, anyway, i've looked around, and found some people complaining about the same, but no working solution so far. The most promising advise was to "extract data in the native format of the GPU". Which i've tried and tried, but failed so far. Edit : by moving the call to glGetTexImage() in a different place, the speed has been a bit improved for the most dramatic samples : looking again at the 8MB texture, it knows requires 500ms, instead of 3sec. It's better, but still much too slow. Smaller texture sizes were not affected by the change (typical timing remained into the 60-80ms range). Using glFinish() didn't help either. Note that, if i call glFinish() (without glGetTexImage), i'm getting a fixed 16ms result, whatever the texture size or complexity. It really looks like the timing for a frame at 60fps. The timing is measured for the full rendering + saving sequence. The call to glGetTexImage() alone does not really matter. That being said, it is this call which changes the performance. And yes, of course, as stated at the beginning, the texture is "created into the GPU", hence the need to save it.

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• Eclipse will not install Android Support Package [migrated]

  - by Michael Mossman

  I am an experienced programmer but new to Android, hence using Eclipse for the first time. Unfortunately I cannot get my first project off the ground. I get as far trying to create the project when the following sequence happens. A screen arrives titled 'Install Dependencies' telling me that the required version is 8 and the installed version is 'Not installed' I click on the Install/Upgrade button and something must happen because Android SDK Manager pops up and I get a whole series of 'Fetching:' messages. The next screen asks me to Choose Package to Install and the only option is Android Support Library, revision 10. This doesn't bother me as I presume 10 is better than 8 so I hit the Install button. This is where it all goes wrong as I get a red message saying: File not found: C:\Program Files (X86)\Android\android-sdk\temp\support_r10.zip (Access is denied). Sure enough, when I check this folder, it is empty. Now, something must have happened as as SDK Manager did a whole lot of fetching and must have put these files somewhere. I am quite happy to find them and put them in the correct folder but the question is what is the name of the files that I am looking for?

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• Why does printf report an error on all but three (ASCII-range) Unicode Codepoints, yet is fine with all others?

  - by fred.bear

  The 'printf' I refer to is the standard-issue "program" (not the built-in): /usr/bin/printf I was testing printf out as a viable method of convert a Unicode Codepoint Hex-literal into its Unicoder character representation, I was looking good, and seemed flawless..(btw. the built-in printf can't do this at all (I think)... I then thought to test it at the lower extreme end of the code-spectrum, and it failed with an avalanche of errors.. All in the ASCII range (= 7 bits) The strangest thing was that 3 value printed normally; they are: $ \u0024 @ \u0040 ` \u0060 I'd like to know what is going on here. The ASCII character-set is most definitely part of the Unicode Code-point sequence.... I am puzzled, and still without a good way to bash script this particular converion.. Suggestions are welcome. To be entertained by that same avalanche of errors, paste the following code into a terminal... # Here is one of the error messages # /usr/bin/printf: invalid universal character name \u0041 # ...for them all, run the following script ( for nib1 in {0..9} {A..F}; do for nib0 in {0..9} {A..F}; do [[ $nib1 < A ]] && nl="\n" || nl=" " $(type -P printf) "\u00$nib1$nib0$nl" done done echo )

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• Discrete Math and Computing Course

  - by ShrimpCrackers

  I was recently admitted into a Computing and Software Systems program (basically software engineering) and one of the first courses I'll be taking is called Mathematical Principles of Computing. The course description: "Integrating mathematical principles with detailed instruction in computer programming. Explores mathematical reasoning and discrete structures through object-oriented programming. Includes algorithm analysis, basic abstract data types, and data structures." I'm not a fan of math, but I've been doing well in all my math classes mostly A's and B's ever since I started two years ago, and I've been doing math every quarter - never took a quarter without math - so I've been doing it all in sequence without gaps. However, I'm worried about this class. I've read briefly on what discrete math is and from what my advisor told me, its connection with computer science is that it has alot to do with proving algorithms. One thing that my instructors briefly touched on and never went into detail was proving algorithms, and when I tried, I just wasn't very good at mathematical induction. It's one of the things that I ignored every time it showed up in a homework problem (usually in Calculus III which I'm finishing up right now). Questions: 1. What can I expect from this class? 2. How can I prepare myself for this class? 3. Other tips? Thank you.

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• Trouble installing from disk

  - by SuperNatural

  I'm writing this in desperation, Windows is slowly killing me and i need to change my home pc os to Ubuntu 11.04 as soon as possible. I created a USB flash drive to install ubuntu, twice, and both times they failed to begin install on restart of my pc. i read on another forum that you might have to change some boot sequence in BIOS but when pressing F2 to enter it didnt work. After a lot of cursing, I made myself an UBUNTU install cd and booted. To my excitement, it now displayed... try ubuntu and install ubuntu. i clicked install ubuntu which lead me to the preparing to install ubuntu display, i checked download updates while installing and clicked forward. The very next display is ' allocate drive space ' i assume there are meant to be options of drives provided but mine is just a blank box and underneath all the options to create a new partition table, add, change, delete and revert are all greyed out. There is a drop down menu labelled 'device for boot loader installlation' but the only option is /dev/sda. when i click install, a no root file system error comes up telling me to please correct from the partitioning menu. I am extremely frustrated. please!! can anyone help me...

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• Working hours for a newbie

  - by martani_net

  This is not a very related software / hardware question, but it's too related to the Tech world. I started a work 3 months before, and I am about to finish this week, and my boss asked me to do a planning of what I've done so far, I think this is totally ok, but he is asking for what I did each day with the hours I spent in these days. This is a sample of what I sent him M T W T F week 29/06 to 03/07 compréhension et analyse du problématique * * architecture de l'application * * * which translates to first task, I spent Monday + Tuesday on, and the last W, T, and Friday. What he is asking for, is what I've done in each day, with the timing I spent on (obviously, I don't think I remember, and because for a programmer, there are no sequence tasks, I mean I change code in a class, then change it in another to fit with the new one and so far) So my question is: is what he asking normal? and if so how can I detail the planning for the 3 months. [update] I used the email account we use to test our software with the extern servers, and I got a good view of what I was doing in every day :), a generic view but it helped too much (PS: The boss doesn't know anything about programming, for him, it's like writing lines and get results back nothing more )

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• Mathematica Programming Language&ndash;An Introduction

  - by JoshReuben

  The Mathematica http://www.wolfram.com/mathematica/ programming model consists of a kernel computation engine (or grid of such engines) and a front-end of notebook instances that communicate with the kernel throughout a session. The programming model of Mathematica is incredibly rich & powerful – besides numeric calculations, it supports symbols (eg Pi, I, E) and control flow logic.   obviously I could use this as a simple calculator: 5 * 10 --> 50 but this language is much more than that!   for example, I could use control flow logic & setup a simple infinite loop: x=1; While [x>0, x=x,x+1] Different brackets have different purposes: square brackets for function arguments:  Cos[x] round brackets for grouping: (1+2)*3 curly brackets for lists: {1,2,3,4} The power of Mathematica (as opposed to say Matlab) is that it gives exact symbolic answers instead of a rounded numeric approximation (unless you request it):   Mathematica lets you define scoped variables (symbols): a=1; b=2; c=a+b --> 5 these variables can contain symbolic values – you can think of these as partially computed functions:   use Clear[x] or Remove[x] to zero or dereference a variable.   To compute a numerical approximation to n significant digits (default n=6), use N[x,n] or the //N prefix: Pi //N -->3.14159 N[Pi,50] --> 3.1415926535897932384626433832795028841971693993751 The kernel uses % to reference the lastcalculation result, %% the 2nd last, %%% the 3rd last etc –> clearer statements: eg instead of: Sqrt[Pi+Sqrt[Sqrt[Pi+Sqrt[Pi]]] do: Sqrt[Pi]; Sqrt[Pi+%]; Sqrt[Pi+%] The help system supports wildcards, so I can search for functions like so: ?Inv* Mathematica supports some very powerful programming constructs and a rich function library that allow you to do things that you would have to write allot of code for in a language like C++.   the Factor function – factorization: Factor[x^3 – 6*x^2 +11x – 6] --> (-3+x) (-2+x) (-1+x)   the Solve function – find the roots of an equation: Solve[x^3 – 2x + 1 == 0] -->   the Expand function – express (1+x)^10 in polynomial form: Expand[(1+x)^10] --> 1+10x+45x^2+120x^3+210x^4+252x^5+210x^6+120x^7+45x^8+10x^9+x^10 the Prime function – what is the 1000th prime? Prime[1000] -->7919 Mathematica also has some powerful graphics capabilities:   the Plot function – plot the graph of y=Sin x in a single period: Plot[Sin[x], {x,0,2*Pi}] you can also plot 3D surfaces of functions using Plot3D function

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• SQL SERVER – A Puzzle – Fun with NULL – Fix Error 8117

  - by pinaldave

  During my 8 years of career, I have been involved in many interviews. Quite often, I act as the  interview. If I am the interviewer, I ask many questions – from easy questions to difficult ones. When I am the interviewee, I frequently get an opportunity to ask the interviewer some questions back. Regardless of the my capacity in attending the interview, I always make it a point to ask the interviewer at least one question. What is NULL? It’s always fun to ask this question during interviews, because in every interview, I get a different answer. NULL is often confused with false, absence of value or infinite value. Honestly, NULL is a very interesting subject as it bases its behavior in server settings. There are a few properties of NULL that are universal, but the knowledge about these properties is not known in a universal sense. Let us run this simple puzzle. Run the following T-SQL script: SELECT SUM(data) FROM (SELECT NULL AS data) t It will return the following error: Msg 8117, Level 16, State 1, Line 1 Operand data type NULL is invalid for sum operator. Now the error makes it very clear that NULL is invalid for sum Operator. Frequently enough, I have showed this simple query to many folks whom I came across. I asked them if they could modify the subquery and return the result as NULL. Here is what I expected: Even though this is a very simple looking query, so far I’ve got the correct answer from only 10% of the people to whom I have asked this question. It was common for me to receive this kind of answer – convert the NULL to some data type. However, doing so usually returns the value as 0 or the integer they passed. SELECT SUM(data) FROM (SELECT ISNULL(NULL,0) AS data) t I usually see many people modifying the outer query to get desired NULL result, but that is not allowed in this simple puzzle. This small puzzle made me wonder how many people have a clear understanding about NULL. Well, here is the answer to my simple puzzle. Just CAST NULL AS INT and it will return the final result as NULL: SELECT SUM(data) FROM (SELECT CAST(NULL AS INT) AS data) t Now that you know the answer, don’t you think it was very simple indeed? This blog post is especially dedicated to my friend Madhivanan who has written an excellent blog post about NULL. I am confident that after reading the blog post from Madhivanan, you will have no confusion regarding NULL in the future. Read: NULL, NULL, NULL and nothing but NULL. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Digital Storage for Airline Entertainment

  - by Bill Evjen

  by Thomas Coughlin Common flash memory cards The most common flash memory products currently in use are SD cards and derivative products (e.g. mini and micro-SD cards) Some compact flash used for professional applications (such as DSLR cameras) Evolution of leading flash formats Standardization –> market expansion Market expansion –> volume iNAND –> focus is on enabling embedded X3 iSSD –> ideal for thin form factor devices Flash memory applications Phones are the #1 user of flash memory Flash memory is used as embedded and removable storage in many mobile applications Flash memory is being used in computers as USB sticks and SSDs Possible use of flash memory in computer combined with HDDs (hybrid HDDs and paired or dual storage computers) It can be a removable card or an embedded card These devices can only handle a specific number of writes Flash memory reads considerably quicker than hard drives Hybrid and dual storage in computers SSDs can provide fast performance but they are expensive HDDs can provide cheap storage but they are relatively slow Combining some flash memory with a HDD can provide costs close to those of HDDs and performance close to flash memory Seagate Momentus XT hybrid HDD Various dual storage offerings putting flash memory with HDDs Other common flash memory devices USB sticks All forms and colors Used for moving files around Some sold with content on them (Sony Movies on USB sticks) Solid State Drives (SSDs) Floating Gate Flash Memory Cell When a bit is programmed, electrons are stored upon the floating gate This has the effect of offsetting the charge on the control gate of the transistor If there is no charge upon the floating gate, then the control gate’s charge determines whether or not a current flows through the channel A strong charge on the control gate assumes that no current flows. A weak charge will allow a strong current to flow through. Similar to HDDs, flash memory must provide: Bit error correction Bad block management NAND and NOR memories are treated differently when it comes to managing wear In many NOR-based systems no management is used at all, since the NOR is simply used to store code, and data is stored in other devices. In this case, it would take a near-infinite amount of time for wear to become an issue since the only time the chip would see an erase/write cycle is when the code in the system is being upgraded, which rarely if ever happens over the life of a typical system. NAND is usually found in very different application than is NOR Flash memory wears out This is expected to get worse over time Retention: Disappearing data Bits fade away Retention decreases with increasing read/writes Bits may change when adjacent bits are read Time and traffic are concerns Controllers typically groom read disturb errors Like DRAM refresh Increases erase/write frequency Application characteristics Music – reads high / writes very low Video – r high / writes very low Internet Cache – r high / writes low On airplanes Many consumers now have their own content viewing devices – do they need the airlines? Is there a way to offer more to consumers, especially with their own viewers Additional special content tie into airplane network access to electrical power, internet Should there be fixed embedded or removable storage for on-board airline entertainment? Is there a way to leverage personal and airline viewers and content in new and entertaining ways?

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• Now Shipping! NetAdvantage for .NET 2010 Volume 3!

  The new NetAdvantage Ultimate includes all four Line of Business user interface control sets for ASP .NET, Windows Forms, WPF and Silverlight plus two advanced Data Visualization UI control sets for WPF and Silverlight. With six NetAdvantage products in one robust package, Infragistics® gives you hundreds of controls and infinite development possibilities. Unified XAML Product Strategy-Share Code, Get More Controls In the 10.3 release, Infragistics continues to deliver code parity between the XAML platforms, WPF and Silverlight. In the line of business toolsets, Infragistics introduces the new xamSchedule™, full-featured, Outlook® 2010-style schedule controls, and the new xamDataTree™, a data bound tree view that comfortably handles tens of thousands of tree nodes. Mimicking our Silverlight Drag and Drop Framework, the WPF Drag and Drop Framework CTP empowers you to add your own rich touches to your applications. Track Users' Behaviors New to all NetAdvantage Silverlight controls is the Infragistics Analytics Framework (IGAF), which empowers you to track user behavior in RIAs running on Silverlight 4. Building on the Microsoft® Silverlight Analytics Framework, with IGAF you can analyze the user's behaviors to ensure the experience you want to deliver. NetAdvantage for Windows Forms--New Office® 2010 Ribbon and Application Menu 2010 Create new experiences with Windows Forms. Now with Office 2010 styling, NetAdvantage for Windows Forms has new features such as Microsoft® Office 2010 ribbon and enhanced Infragistics.Excel to export the contents of the high performance WinGrid™ into Microsoft Excel® 2010. The new Windows Message Support enables Infragistics standalone editor controls to process numerous Windows® OS messages, allowing them to respond just like native controls to changes in the Windows environment. Create Faster Web 2.0 Experiences with NetAdvantage for ASP .NET Infragistics continues to push the envelope to deliver the fastest ASP .NET WebForms controls available on the market. Our lightning fast ASP .NET grids are now enhanced with XPS/PDF Exporting and Summary Rows. This release also includes support for jQuery Templating (as a CTP) within our WebDataGrid™ and WebDataTree™ controls allowing you to quickly cut down overall page size. Deliver Business Intelligence with Power, Flexibility and the Office 2010 Experience NetAdvantage for WPF Data Visualization and NetAdvantage for Silverlight Data Visualization help you deliver flexible, powerful and usable end user experiences in Business Intelligence applications. Both suites include the Pivot Grid that delivers the full power of online analytical processing (OLAP) to present multi-dimensional data, sliced and diced in cross-tabulated form for end users to drill down into, interact with and easily extract meaning from the data. Mapping Made Easy 10.3 marks the official release of the WPF Data Visualization xamMap™ control to map anything and everything from geographic to geo-spacial mapping data. Map layers allow you to add successive levels of detail, navigational panes for panning in all directions, color swatch panes that facilitate value scales like Choropleth shading, and scale panes allowing users to zoom-in and out. Both toolsets introduce the first of many relationship maps! With the xamOrgChart™ CTP you can map out organizational charts of up to 50K employees, competitive brackets (think World Cup) and any other relational, organizational map your application needs. http://www.infragistics.com span.fullpost {display:none;}

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• Game of Phones

  - by Carlos Chang

  Game  of  Phones There’s an excellent DZone article titled: 2014 Guide to Mobile Development. It’s loaded with excellent information including some results from a mobile related survey to more than 1000 IT professionals. Without giving away too much, these highlights should convince you to read the entire article.  Web and Hybrid apps are gaining tons of traction particularly in the enterprise. If you want to better understand the differences between Web, Native and Hybrid, this article has you covered. Enterprise developers are increasingly more interested in cross platform tools. Makes sense right?  I mean, unless you have infinite resources (e.g. Facebook) and can afford to write native apps to every platform, finding something that can meet your needs for iOS and Android makes sense.  And toss in the possibility of Windows Phone …and oh, just to be current, the addition of Apple’s new mobile language, Swift, to add to Objective C.. and oh boy.  Why not check out cross platform tools? BTW, don’t  forget testing on each platform, and maintenance and the next versions of the app. It’s not one and done. If you’re successful, you’re never done. Various mobile vendors are represented and many provide some great information.  Oracle's own Suhas Uliyar, VP of Mobile Strategy, represented with some great insights into the challenges of mobile back end integration (SOA, mBaaS, etc.) and moving from "mobile first" to a mobile plus world. BTW, Suhas was recently named Top 100 Wireless Technology Experts for 2014 by Today's Wireless World magazine.  And if your not yet convinced, DZone did a very nice job with their mobile infographic stylized after the insanely popular series, Game of Thrones.  Even though there were no dragons illustrated, worth the price of admission just for that.   Check it out here.

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