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• ArchBeat Link-o-Rama Top 10 for October 2012

  - by Bob Rhubart

  The Top 10 most popular items shared on the OTN ArchBeat Facebook Page for October 2012. OAM/OVD JVM Tuning | @FusionSecExpert Vinay from the Oracle Fusion Middleware Architecture Group (known as the A-Team) shares a process for analyzing and improving performance in Oracle Virtual Directory and Oracle Access Manager. SOA Galore: New Books for Technical Eyes Only Shake up up your technical skills with this trio of new technical books from community members covering SOA and BPM. Clustering ODI11g for High-Availability Part 1: Introduction and Architecture | Richard Yeardley "JEE agents can be deployed alongside, or instead of, standalone agents," says Rittman Meade's Richard Yeardley. "But there is one key advantage in using JEE agents and WebLogic – when you deploy JEE agents as part of a WebLogic cluster they can be configured together to form a high availability cluster." Learn more in Yeardley's extensive post. Solving Big Problems in Our 21st Century Information Society | Irving Wladawsky-Berger "I believe that the kind of extensive collaboration between the private sector, academia and government represented by the Internet revolution will be the way we will generally tackle big problems in the 21st century. Just as with the Internet, governments have a major role to play as the catalyst for many of the big projects that the private sector will then take forward and exploit. The need for high bandwidth, robust national broadband infrastructures is but one such example." -- Irving Wladawsky-Berger Eventually, 90% of tech budgets will be outside IT departments | ZDNet Another interesting post from ZDNet blogger Joe McKendrick about changing roles in IT. ADF Mobile - Login Functionality | Andrejus Baranovskis "The new ADF Mobile approach with native deployment is cool when you want to access phone functionality (camera, email, sms and etc.), also when you want to build mobile applications with advanced UI," reports Oracle ACE Director Andrejus Baranovskis. Podcast: Are You Future Proof? - Part 2 In Part 2, practicing architects and Oracle ACE Directors Ron Batra (AT&T), Basheer Khan (Innowave Technology), and Ronald van Luttikhuizen (Vennster) discuss re-tooling one’s skill set to reflect changes in enterprise IT, including the knowledge to steer stakeholders around the hype to what's truly valuable. ADF Mobile Custom Javascript — iFrame Injection | John Brunswick The ADF Mobile Framework provides a range of out of the box components to add within your AMX pages, according to John Brunswick. But what happens when "an out of the box component does not directly fulfill your development need? What options are available to extend your application interface?" John has an answer. Oracle Solaris 11.1 update focuses on database integration, cloud | Mark Fontecchio TechTarget editor Mark Fontecchio reports on the recent Oracle Solaris 11.1 release, with comments from IDC's Al Gillen. Architects Matter: Making sense of the people who make sense of enterprise IT Why do architects matter? Oracle Enterprise Architect Eric Stephens suggests that you ask yourself this question the next time you take the elevator to the Oracle offices on the 45th floor of the Willis Tower in Chicago, Illinois (or any other skyscraper, for that matter). If you had to take the stairs to get to those offices, who would you blame? "You get the picture," he says. "Architecture is essential for any necessarily complex structure, be it a building or an enterprise." (Read the article) Thought for the Day "I will contend that conceptual integrity is the most important consideration in system design. It is better to have a system omit certain anomalous features and improvements, but to reflect one set of design ideas, than to have one that contains many good but independent and uncoordinated ideas." — Frederick P. Brooks Source: SoftwareQuotes.com

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• How do you formulate the Domain Model in Domain Driven Design properly (Bounded Contexts, Domains)?

  - by lko

  Say you have a few applications which deal with a few different Core Domains. The examples are made up and it's hard to put a real example with meaningful data together (concisely). In Domain Driven Design (DDD) when you start looking at Bounded Contexts and Domains/Sub Domains, it says that a Bounded Context is a "phase" in a lifecycle. An example of Context here would be within an ecommerce system. Although you could model this as a single system, it would also warrant splitting into separate Contexts. Each of these areas within the application have their own Ubiquitous Language, their own Model, and a way to talk to other Bounded Contexts to obtain the information they need. The Core, Sub, and Generic Domains are the area of expertise and can be numerous in complex applications. Say there is a long process dealing with an Entity for example a Book in a core domain. Now looking at the Bounded Contexts there can be a number of phases in the books life-cycle. Say outline, creation, correction, publish, sale phases. Now imagine a second core domain, perhaps a store domain. The publisher has its own branch of stores to sell books. The store can have a number of Bounded Contexts (life-cycle phases) for example a "Stock" or "Inventory" context. In the first domain there is probably a Book database table with basically just an ID to track the different book Entities in the different life-cycles. Now suppose you have 10+ supporting domains e.g. Users, Catalogs, Inventory, .. (hard to think of relevant examples). For example a DomainModel for the Book Outline phase, the Creation phase, Correction phase, Publish phase, Sale phase. Then for the Store core domain it probably has a number of life-cycle phases. public class BookId : Entity { public long Id { get; set; } } In the creation phase (Bounded Context) the book could be a simple class. public class Book : BookId { public string Title { get; set; } public List<string> Chapters { get; set; } //... } Whereas in the publish phase (Bounded Context) it would have all the text, release date etc. public class Book : BookId { public DateTime ReleaseDate { get; set; } //... } The immediate benefit I can see in separating by "life-cycle phase" is that it's a great way to separate business logic so there aren't mammoth all-encompassing Entities nor Domain Services. A problem I have is figuring out how to concretely define the rules to the physical layout of the Domain Model. A. Does the Domain Model get "modeled" so there are as many bounded contexts (separate projects etc.) as there are life-cycle phases across the core domains in a complex application? Edit: Answer to A. Yes, according to the answer by Alexey Zimarev there should be an entire "Domain" for each bounded context. B. Is the Domain Model typically arranged by Bounded Contexts (or Domains, or both)? Edit: Answer to B. Each Bounded Context should have its own complete "Domain" (Service/Entities/VO's/Repositories) C. Does it mean there can easily be 10's of "segregated" Domain Models and multiple projects can use it (the Entities/Value Objects)? Edit: Answer to C. There is a complete "Domain" for each Bounded Context and the Domain Model (Entity/VO layer/project) isn't "used" by the other Bounded Contexts directly, only via chosen paths (i.e. via Domain Events). The part that I am trying to figure out is how the Domain Model is actually implemented once you start to figure out your Bounded Contexts and Core/Sub Domains, particularly in complex applications. The goal is to establish the definitions which can help to separate Entities between the Bounded Contexts and Domains.

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• An Actionable Common Approach to Federal Enterprise Architecture

  - by TedMcLaughlan

  The recent “Common Approach to Federal Enterprise Architecture” (US Executive Office of the President, May 2 2012) is extremely timely and well-organized guidance for the Federal IT investment and deployment community, as useful for Federal Departments and Agencies as it is for their stakeholders and integration partners. The guidance not only helps IT Program Planners and Managers, but also informs and prepares constituents who may be the beneficiaries or otherwise impacted by the investment. The FEA Common Approach extends from and builds on the rapidly-maturing Federal Enterprise Architecture Framework (FEAF) and its associated artifacts and standards, already included to a large degree in the annual Federal Portfolio and Investment Management processes – for example the OMB’s Exhibit 300 (i.e. Business Case justification for IT investments).A very interesting element of this Approach includes the very necessary guidance for actually using an Enterprise Architecture (EA) and/or its collateral – good guidance for any organization charged with maintaining a broad portfolio of IT investments. The associated FEA Reference Models (i.e. the BRM, DRM, TRM, etc.) are very helpful frameworks for organizing, understanding, communicating and standardizing across agencies with respect to vocabularies, architecture patterns and technology standards. Determining when, how and to what level of detail to include these reference models in the typically long-running Federal IT acquisition cycles wasn’t always clear, however, particularly during the first interactions of a Program’s technical and functional leadership with the Mission owners and investment planners. This typically occurs as an agency begins the process of describing its strategy and business case for allocation of new Federal funding, reacting to things like new legislation or policy, real or anticipated mission challenges, or straightforward ROI opportunities (for example the introduction of new technologies that deliver significant cost-savings).The early artifacts (i.e. Resource Allocation Plans, Acquisition Plans, Exhibit 300’s or other Business Case materials, etc.) of the intersection between Mission owners, IT and Program Managers are far easier to understand and discuss, when the overlay of an evolved, actionable Enterprise Architecture (such as the FEA) is applied.  “Actionable” is the key word – too many Public Service entity EA’s (including the FEA) have for too long been used simply as a very highly-abstracted standards reference, duly maintained and nominally-enforced by an Enterprise or System Architect’s office. Refreshing elements of this recent FEA Common Approach include one of the first Federally-documented acknowledgements of the “Solution Architect” (the “Problem-Solving” role). This role collaborates with the Enterprise, System and Business Architecture communities primarily on completing actual “EA Roadmap” documents. These are roadmaps grounded in real cost, technical and functional details that are fully aligned with both contextual expectations (for example the new “Digital Government Strategy” and its required roadmap deliverables - and the rapidly increasing complexities of today’s more portable and transparent IT solutions.  We also expect some very critical synergies to develop in early IT investment cycles between this new breed of “Federal Enterprise Solution Architect” and the first waves of the newly-formal “Federal IT Program Manager” roles operating under more standardized “critical competency” expectations (including EA), likely already to be seriously influencing the quality annual CPIC (Capital Planning and Investment Control) processes.  Our Oracle Enterprise Strategy Team (EST) and associated Oracle Enterprise Architecture (OEA) practices are already engaged in promoting and leveraging the visibility of Enterprise Architecture as a key contributor to early IT investment validation, and we look forward in particular to seeing the real, citizen-centric benefits of this FEA Common Approach in particular surface across the entire Public Service CPIC domain - Federal, State, Local, Tribal and otherwise. Read more Enterprise Architecture blog posts for additional EA insight!

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• Velocity collision detection (2D)

  - by ultifinitus

  Alright, so I have made a simple game engine (see youtube) And my current implementation of collision resolution has a slight problem, involving the velocity of a platform. Basically I run through all of the objects necessary to detect collisions on and resolve those collisions as I find them. Part of that resolution is setting the player's velocity = the platform's velocity. Which works great! Unless I have a row of platforms moving at different velocities or a platform between a stack of tiles.... (current system) bool player::handle_collisions() { collisions tcol; bool did_handle = false; bool thisObjectHandle = false; for (int temp = 0; temp < collideQueue.size(); temp++) { thisObjectHandle = false; tcol = get_collision(prevPos.x,y,get_img()->get_width(),get_img()->get_height(), collideQueue[temp]->get_position().x,collideQueue[temp]->get_position().y, collideQueue[temp]->get_img()->get_width(),collideQueue[temp]->get_img()->get_height()); if (prevPos.y >= collideQueue[temp]->get_prev_pos().y + collideQueue[temp]->get_img()->get_height()) if (tcol.top > 0) { add_pos(0,tcol.top); set_vel(get_vel().x,collideQueue[temp]->get_vel().y); thisObjectHandle = did_handle = true; } if (prevPos.y + get_img()->get_height() <= collideQueue[temp]->get_prev_pos().y) if (tcol.bottom > 0) { add_pos(collideQueue[temp]->get_vel().x,-tcol.bottom); set_vel(get_vel().x/*collideQueue[temp]->get_vel().x*/,collideQueue[temp]->get_vel().y); ableToJump = true; jumpTimes = maxjumpable; thisObjectHandle = did_handle = true; } /// /// ADD CODE FROM NEXT CODE BLOCK HERE (on forum, not in code) /// } for (int temp = 0; temp < collideQueue.size(); temp++) { thisObjectHandle = false; tcol = get_collision(x,y,get_img()->get_width(),get_img()->get_height(), collideQueue[temp]->get_position().x,collideQueue[temp]->get_position().y, collideQueue[temp]->get_img()->get_width(),collideQueue[temp]->get_img()->get_height()); if (prevPos.x + get_img()->get_width() <= collideQueue[temp]->get_prev_pos().x) if (tcol.left > 0) { add_pos(-tcol.left,0); set_vel(collideQueue[temp]->get_vel().x,get_vel().y); thisObjectHandle = did_handle = true; } if (prevPos.x >= collideQueue[temp]->get_prev_pos().x + collideQueue[temp]->get_img()->get_width()) if (tcol.right > 0) { add_pos(tcol.right,0); set_vel(collideQueue[temp]->get_vel().x,get_vel().y); thisObjectHandle = did_handle = true; } } return did_handle; } (if I add the following code {where the comment to do so is}, which is glitchy, the above problem doesn't happen, though it brings others) if (!thisObjectHandle) { if (tcol.bottom > tcol.top) { add_pos(collideQueue[temp]->get_vel().x,-tcol.bottom); set_vel(get_vel().x,collideQueue[temp]->get_vel().y); } else if (tcol.top > tcol.bottom) { add_pos(0,tcol.top); set_vel(get_vel().x,collideQueue[temp]->get_vel().y); } } How would you change my system to prevent this?

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• Utility to Script SQL Server Configuration

  - by Bill Graziano

  I wrote a small utility to script some key SQL Server configuration information. I had two goals for this utility: Assist with disaster recovery preparation Identify configuration changes I’ve released the application as open source through CodePlex. You can download it from CodePlex at the Script SQL Server Configuration project page. The application is a .NET 2.0 console application that uses SMO. It writes its output to a directory that you specify.  Disaster Planning ScriptSqlConfig generates scripts for logins, jobs and linked servers.  It writes the properties and configuration from the instance to text files. The scripts are designed so they can be run against a DR server in the case of a disaster. The properties and configuration will need to be manually compared. Each job is scripted to its own file. Each linked server is scripted to its own file. The linked servers don’t include the password if you use a SQL Server account to connect to the linked server. You’ll need to store those somewhere secure. All the logins are scripted to a single file. This file includes windows logins, SQL Server logins and any server role membership.  The SQL Server logins are scripted with the correct SID and hashed passwords. This means that when you create the login it will automatically match up to the users in the database and have the correct password. This is the only script that I programmatically generate rather than using SMO. The SQL Server configuration and properties are scripted to text files. These will need to be manually reviewed in the event of a disaster. Or you could DIFF them with the configuration on the new server. Configuration Changes These scripts and files are all designed to be checked into a version control system.  The scripts themselves don’t include any date specific information. In my environments I run this every night and check in the changes. I call the application once for each server and script each server to its own directory.  The process will delete any existing files before writing new ones. This solved the problem I had where the scripts for deleted jobs and linked servers would continue to show up.  To see any changes I just need to query the version control system to show many any changes to the files. Database Scripting Utilities that script database objects are plentiful.  CodePlex has at least a dozen of them including one I wrote years ago. The code is so easy to write it’s hard not to include that functionality. This functionality wasn’t high on my list because it’s included in a database backup.  Unless you specify the /nodb option, the utility will script out many user database objects. It will script one object per file. It will script tables, stored procedures, user-defined data types, views, triggers, table types and user-defined functions. I know there are more I need to add but haven’t gotten around it yet. If there’s something you need, please log an issue and get it added. Since it scripts one object per file these really aren’t appropriate to recreate an empty database. They are really good for checking into source control every night and then seeing what changed. I know everyone tells me all their database objects are in source control but a little extra insurance never hurts. Conclusion I hope this utility will help a few of you out there. My goal is to have it script all server objects that aren’t contained in user databases. This should help with configuration changes and especially disaster recovery.

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• The Best Data Integration for Exadata Comes from Oracle

  - by maria costanzo

  Oracle Data Integrator and Oracle GoldenGate offer unique and optimized data integration solutions for Oracle Exadata. For example, customers that choose to feed their data warehouse or reporting database with near real-time throughout the day, can do so without decreasing  performance or availability of source and target systems. And if you ask why real-time, the short answer is: in today’s fast-paced, always-on world, business decisions need to use more relevant, timely data to be able to act fast and seize opportunities. A longer response to "why real-time" question can be found in a related blog post. If we look at the solution architecture, as shown on the diagram below,  Oracle Data Integrator and Oracle GoldenGate are both uniquely designed to take full advantage of the power of the database and to eliminate unnecessary middle-tier components. Oracle Data Integrator (ODI) is the best bulk data loading solution for Exadata. ODI is the only ETL platform that can leverage the full power of Exadata, integrate directly on the Exadata machine without any additional hardware, and by far provides the simplest setup and fastest overall performance on an Exadata system. We regularly see customers achieving a 5-10 times boost when they move their ETL to ODI on Exadata. For  some companies the performance gain is even much higher. For example a large insurance company did a proof of concept comparing ODI vs a traditional ETL tool (one of the market leaders) on Exadata. The same process that was taking 5hrs and 11 minutes to complete using the competing ETL product took 7 minutes and 20 seconds with ODI. Oracle Data Integrator was 42 times faster than the conventional ETL when running on Exadata.This shows that Oracle's own data integration offering helps you to gain the most out of your Exadata investment with a truly optimized solution. GoldenGate is the best solution for streaming data from heterogeneous sources into Exadata in real time. Oracle GoldenGate can also be used together with Data Integrator for hybrid use cases that also demand non-invasive capture, high-speed real time replication. Oracle GoldenGate enables real-time data feeds from heterogeneous sources non-invasively, and delivers to the staging area on the target Exadata system. ODI runs directly on Exadata to use the database engine power to perform in-database transformations. Enterprise Data Quality is integrated with Oracle Data integrator and enables ODI to load trusted data into the data warehouse tables. Only Oracle can offer all these technical benefits wrapped into a single intelligence data warehouse solution that runs on Exadata. Compared to traditional ETL with add-on CDC this solution offers: §  Non-invasive data capture from heterogeneous sources and avoids any performance impact on source §  No mid-tier; set based transformations use database power §  Mini-batches throughout the day –or- bulk processing nightly which means maximum availability for the DW §  Integrated solution with Enterprise Data Quality enables leveraging trusted data in the data warehouse In addition to Starwood Hotels and Resorts, Morrison Supermarkets, United Kingdom’s fourth-largest food retailer, has seen the power of this solution for their new BI platform and shared their story with us. Morrisons needed to analyze data across a large number of manufacturing, warehousing, retail, and financial applications with the goal to achieve single view into operations for improved customer service. The retailer deployed Oracle GoldenGate and Oracle Data Integrator to bring new data into Oracle Exadata in near real-time and replicate the data into reporting structures within the data warehouse—extending visibility into operations. Using Oracle's data integration offering for Exadata, Morrisons produced financial reports in seconds, rather than minutes, and improved staff productivity and agility. You can read more about Morrison’s success story here and hear from Starwood here. From an Irem Radzik article.

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• LUKOIL Overseas Holding Optimizes Oil Field Development Projects with Integrated Project Management

  - by Melissa Centurio Lopes

  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;} LUKOIL Overseas Group is a growing oil and gas company that is an integral part of the vertically integrated oil company OAO LUKOIL. It is engaged in the exploration, acquisition, integration, and efficient development of oil and gas fields outside the Russian Federation to promote transforming LUKOIL into a transnational energy company. In 2010, the company signed a 20-year development project for the giant, West Qurna 2 oil field in Iraq. Executing 10,000 to 15,000 project activities simultaneously on 14 major construction and drilling projects in Iraq for the West Qurna-2 project meant the company needed a clear picture, in real time, of dependencies between its capital construction, geologic exploration and sinking projects—required for its building infrastructure oil field development projects in Iraq. LUKOIL Overseas Holding deployed Oracle’s Primavera P6 Enterprise Project Portfolio Management to generate structured project management information and optimize planning, monitoring, and analysis of all engineering and commercial activities—such as tenders, and bulk procurement of materials and equipment—related to oil field development projects. A word from LUKOIL Overseas Holding Ltd. “Previously, we created project schedules on desktop computers and uploaded them to the project server to be merged into one big file for each project participant to access. This was not scalable, as we’ve grown and now run up to 15,000 activities in numerous projects and subprojects at any time. With Oracle’s Primavera P6 Enterprise Project Portfolio Management, we can now work concurrently on projects with many team members, enjoy absolute security, and issue new baselines for all projects and project participants once a week, with ease.” – Sergey Kotov, Head of IT and the Communication Office, LUKOIL Mid-East Ltd. Oracle Primavera Solutions: · Facilitated managing dependencies between projects by enabling the general scheduler to reschedule all projects and subprojects once a week, realigning 10,000 to 15,000 project activities that the company runs at any time · Replaced Microsoft Project and a paper-based system with a complete solution that provides structured project data · Enhanced data security by establishing project management security policies that enable only authorized project members to edit their project tasks, while enabling each project participant to view all project data that are relevant to that individual’s task · Enabled the company to monitor project progress in comparison to the projected plan, based on physical project assets to determine if each project is on track to conclude within its time and budget limitations To view the full list of solutions view here. “Oracle Gold Partner Parma Telecom was key to our successful Primavera deployment, implementing the software’s basic functionalities, such as project content, timeframes management, and cost management, in addition to performing its integration with our enterprise resource planning system and intranet portal within ten months and in accordance with budgets,” said Rafik Baynazarov, head of the master planning and control office, LUKOIL Mid-East Ltd. “ To read the full version of the customer success story, please view here.

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• Easy Made Easier - Networking

  - by dragonfly

      In my last post, I highlighted the feature of the Appliance Manager Configurator to auto-fill some fields based on previous field values, including host names based on System Name and sequential IP addresses from the first IP address entered. This can make configuration a little faster and a little less subject to data entry errors, particularly if you are doing the configuration on the Oracle Database Appliance itself.     The Oracle Database Appliance Appliance Manager Configurator is available for download here. But why would you download it, if it comes pre-installed on the Oracle Database Appliance? A common reason for customers interested in this new Engineered System is to get a good idea of how easy it is to configure. Beyond that, you can save the resulting configuration as a file, and use it on an Oracle Database Appliance. This allows you to verify the data entered in advance, and in the comfort of your office. In addition, the topic of this post is another strong reason to download and use the Appliance Manager Configurator prior to deploying your Oracle Database Appliance.     The most common source of hiccups in deploying an Oracle Database Appliance, based on my experiences with a variety of customers, involves the network configuration. It is during Step 11, when network validation occurs, that these come to light, which is almost half way through the 24 total steps, and can be frustrating, whether it was a typo, DNS mis-configuration or IP address already in use. This is why I recommend as a best practice taking advantage of the Appliance Manager Configurator prior to deploying an Oracle Database Appliance.     Why? Not only do you get the benefit of being able to double check your entries before you even start on the Oracle Database Appliance, you can also take advantage of the Network Validation step. This is the final step before you review all the data and can save it to a text file. It can be skipped, if you aren't ready or are not connected to the network that the Oracle Database Appliance will be on. My recommendation, though, is to run the Appliance Manager Configurator on your laptop, enter the data or re-load a previously saved file of the data, and then connect to the network that the Oracle Database Appliance will be on. Now run the Network Validation. It will check to make sure that the host names you entered are in DNS and do resolve to the IP addresses you specifiied. It will also ping the IP Addresses you specified, so that you can verify that no other machine is already using them (yes, that has happened at customer sites).     After you have completed the validation, as seen in the screen shot below, you can review the results and move on to saving your settings to a file for use on your Oracle Database Appliance, or if there are errors, you can use the Back button to return to the appropriate screen and correct the data. Once you are satisfied with the Network Validation, just check the Skip/Ignore Network Validation checkbox at the top of the screen, then click Next. Is the Network Validation in the Appliance Manager Configurator required? No, but it can save you time later. I should also note that the Network Validation screen is not part of the Appliance Manager Configurator that currently ships on the Oracle Database Appliance, so this is the easiest way to verify your network configuration.     I hope you are finding this series of posts useful. My next post will cover some aspects of the windowing environment that gets run by the 'startx' command on the Oracle Database Appliance, since this is needed to run the Appliance Manager Configurator via a direct connected monitor, keyboard and mouse, or via the ILOM. If it's been a while since you've used an OpenWindows environment, you'll want to check it out.

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• XNA Multiplayer Games and Networking

  - by JoshReuben

  ·        XNA communication must by default be lightweight – if you are syncing game state between players from the Game.Update method, you must minimize traffic. That game loop may be firing 60 times a second and player 5 needs to know if his tank has collided with any player 3 and the angle of that gun turret. There are no WCF ServiceContract / DataContract niceties here, but at the same time the XNA networking stack simplifies the details. The payload must be simplistic - just an ordered set of numbers that you would map to meaningful enum values upon deserialization.   Overview ·        XNA allows you to create and join multiplayer game sessions, to manage game state across clients, and to interact with the friends list ·        Dependency on Gamer Services - to receive notifications such as sign-in status changes and game invitations ·        two types of online multiplayer games: system link game sessions (LAN) and LIVE sessions (WAN). ·        Minimum dev requirements: 1 Xbox 360 console + Creators Club membership to test network code - run 1 instance of game on Xbox 360, and 1 on a Windows-based computer   Network Sessions ·        A network session is made up of players in a game + up to 8 arbitrary integer properties describing the session ·        create custom enums – (e.g. GameMode, SkillLevel) as keys in NetworkSessionProperties collection ·        Player state: lobby, in-play   Session Types ·        local session - for split-screen gaming - requires no network traffic. ·        system link session - connects multiple gaming machines over a local subnet. ·        Xbox LIVE multiplayer session - occurs on the Internet. Ranked or unranked   Session Updates ·        NetworkSession class Update method - must be called once per frame. ·        performs the following actions: o   Sends the network packets. o   Changes the session state. o   Raises the managed events for any significant state changes. o   Returns the incoming packet data. ·        synchronize the session à packet-received and state-change events à no threading issues   Session Config ·        Session host - gaming machine that creates the session. XNA handles host migration ·        NetworkSession properties: AllowJoinInProgress , AllowHostMigration ·        NetworkSession groups: AllGamers, LocalGamers, RemoteGamers   Subscribe to NetworkSession events ·        GamerJoined ·        GamerLeft ·        GameStarted ·        GameEnded – use to return to lobby ·        SessionEnded – use to return to title screen   Create a Session session = NetworkSession.Create(         NetworkSessionType.SystemLink,         maximumLocalPlayers,         maximumGamers,         privateGamerSlots,         sessionProperties );   Start a Session if (session.IsHost) {     if (session.IsEveryoneReady)     {        session.StartGame();        foreach (var gamer in SignedInGamer.SignedInGamers)        {             gamer.Presence.PresenceMode =                 GamerPresenceMode.InCombat;   Find a Network Session AvailableNetworkSessionCollection availableSessions = NetworkSession.Find(     NetworkSessionType.SystemLink,       maximumLocalPlayers,     networkSessionProperties); availableSessions.AllowJoinInProgress = true;   Join a Network Session NetworkSession session = NetworkSession.Join(     availableSessions[selectedSessionIndex]);   Sending Network Data var packetWriter = new PacketWriter(); foreach (LocalNetworkGamer gamer in session.LocalGamers) {     // Get the tank associated with this player.     Tank myTank = gamer.Tag as Tank;     // Write the data.     packetWriter.Write(myTank.Position);     packetWriter.Write(myTank.TankRotation);     packetWriter.Write(myTank.TurretRotation);     packetWriter.Write(myTank.IsFiring);     packetWriter.Write(myTank.Health);       // Send it to everyone.     gamer.SendData(packetWriter, SendDataOptions.None);     }   Receiving Network Data foreach (LocalNetworkGamer gamer in session.LocalGamers) {     // Keep reading while packets are available.     while (gamer.IsDataAvailable)     {         NetworkGamer sender;          // Read a single packet.         gamer.ReceiveData(packetReader, out sender);          if (!sender.IsLocal)         {             // Get the tank associated with this packet.             Tank remoteTank = sender.Tag as Tank;              // Read the data and apply it to the tank.             remoteTank.Position = packetReader.ReadVector2();             …   End a Session if (session.AllGamers.Count == 1)         {             session.EndGame();             session.Update();         }   Performance •        Aim to minimize payload, reliable in order messages •        Send Data Options: o   Unreliable, out of order -(SendDataOptions.None) o   Unreliable, in order (SendDataOptions.InOrder) o   Reliable, out of order (SendDataOptions.Reliable) o   Reliable, in order (SendDataOptions.ReliableInOrder) o   Chat data (SendDataOptions.Chat) •        Simulate: NetworkSession.SimulatedLatency , NetworkSession.SimulatedPacketLoss •        Voice support – NetworkGamer properties: HasVoice ,IsTalking , IsMutedByLocalUser

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• Solaris 11.1: Encrypted Immutable Zones on (ZFS) Shared Storage

  - by darrenm

  Solaris 11 brought both ZFS encryption and the Immutable Zones feature and I've talked about the combination in the past.  Solaris 11.1 adds a fully supported method of storing zones in their own ZFS using shared storage so lets update things a little and put all three parts together. When using an iSCSI (or other supported shared storage target) for a Zone we can either let the Zones framework setup the ZFS pool or we can do it manually before hand and tell the Zones framework to use the one we made earlier.  To enable encryption we have to take the second path so that we can setup the pool with encryption before we start to install the zones on it. We start by configuring the zone and specifying an rootzpool resource: # zonecfg -z eizoss Use 'create' to begin configuring a new zone. zonecfg:eizoss> create create: Using system default template 'SYSdefault' zonecfg:eizoss> set zonepath=/zones/eizoss zonecfg:eizoss> set file-mac-profile=fixed-configuration zonecfg:eizoss> add rootzpool zonecfg:eizoss:rootzpool> add storage \ iscsi://zs7120-tvp540-c.uk.oracle.com/luname.naa.600144f09acaacd20000508e64a70001 zonecfg:eizoss:rootzpool> end zonecfg:eizoss> verify zonecfg:eizoss> commit zonecfg:eizoss> Now lets create the pool and specify encryption: # suriadm map \ iscsi://zs7120-tvp540-c.uk.oracle.com/luname.naa.600144f09acaacd20000508e64a70001 PROPERTY VALUE mapped-dev /dev/dsk/c10t600144F09ACAACD20000508E64A70001d0 # echo "zfscrypto" > /zones/p # zpool create -O encryption=on -O keysource=passphrase,file:///zones/p eizoss \ /dev/dsk/c10t600144F09ACAACD20000508E64A70001d0 # zpool export eizoss Note that the keysource example above is just for this example, realistically you should probably use an Oracle Key Manager or some other better keystorage, but that isn't the purpose of this example.  Note however that it does need to be one of file:// https:// pkcs11: and not prompt for the key location.  Also note that we exported the newly created pool.  The name we used here doesn't actually mater because it will get set properly on import anyway. So lets go ahead and do our install: zoneadm -z eizoss install -x force-zpool-import Configured zone storage resource(s) from: iscsi://zs7120-tvp540-c.uk.oracle.com/luname.naa.600144f09acaacd20000508e64a70001 Imported zone zpool: eizoss_rpool Progress being logged to /var/log/zones/zoneadm.20121029T115231Z.eizoss.install Image: Preparing at /zones/eizoss/root. AI Manifest: /tmp/manifest.xml.ujaq54 SC Profile: /usr/share/auto_install/sc_profiles/enable_sci.xml Zonename: eizoss Installation: Starting ... Creating IPS image Startup linked: 1/1 done Installing packages from: solaris origin: http://pkg.us.oracle.com/solaris/release/ Please review the licenses for the following packages post-install: consolidation/osnet/osnet-incorporation (automatically accepted, not displayed) Package licenses may be viewed using the command: pkg info --license <pkg_fmri> DOWNLOAD PKGS FILES XFER (MB) SPEED Completed 187/187 33575/33575 227.0/227.0 384k/s PHASE ITEMS Installing new actions 47449/47449 Updating package state database Done Updating image state Done Creating fast lookup database Done Installation: Succeeded Note: Man pages can be obtained by installing pkg:/system/manual done. Done: Installation completed in 929.606 seconds. Next Steps: Boot the zone, then log into the zone console (zlogin -C) to complete the configuration process. Log saved in non-global zone as /zones/eizoss/root/var/log/zones/zoneadm.20121029T115231Z.eizoss.install That was really all we had to do, when the install is done boot it up as normal. The zone administrator has no direct access to the ZFS wrapping keys used for the encrypted pool zone is stored on.  Due to how inheritance works in ZFS he can still create new encrypted datasets that use those wrapping keys (without them ever being inside a process in the zone) or he can create encrypted datasets inside the zone that use keys of his own choosing, the output below shows the two cases: rpool is inheriting the key material from the global zone (note we can see the value of the keysource property but we don't use it inside the zone nor does that path need to be (or is) accessible inside the zone). Whereas rpool/export/home/bob has set keysource locally. # zfs get encryption,keysource rpool rpool/export/home/bob NAME PROPERTY VALUE SOURCE rpool encryption on inherited from $globalzone rpool keysource passphrase,file:///zones/p inherited from $globalzone rpool/export/home/bob encryption on local rpool/export/home/bob keysource passphrase,prompt local  

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• Taking HRMS to the Cloud to Simplify Human Resources Management

  - by HCM-Oracle

  By Anke Mogannam With human capital management (HCM) a top-of-mind issue for executives in every industry, human resources (HR) organizations are poised to have their day in the sun—proving not just their administrative worth but their strategic value as well.  To make good on that promise, however, HR must modernize. Indeed, if HR is to act as an agent of change—providing the swift reallocation of employees  and the rapid absorption of employee data required for enterprises to shift course on a dime—it must first deal with the disruptive change at its own front door. And increasingly, that means choosing the right technology and human resources management system (HRMS) for managing the entire employee lifecycle. Unfortunately, for most organizations, this task has proved easier said than done. This is because while much has been written about advances in HRMS technology, until recently, most of those advances took the form of disparate on-premises solutions designed to serve very specific purposes. Although this may have resulted in key competencies in certain areas, it also meant that processes for core HR functions like payroll and benefits were being carried out in separate systems from those used for talent management, workforce optimization, training, and so on. With no integration—and no single system of record—processes were disconnected, ease of use was impeded, user experience was diminished, and vital data was left untapped.  Today, however, that scenario has begun to change, and end-to-end cloud-based HCM solutions have moved from wished-for innovations to real-life solutions. Why, then, have HR organizations been so slow in adopting them? The answer—it would seem—is, “It’s complicated.” So complicated, in fact, that 45 percent of the respondents to PwC’s “Annual HR Technology Survey” (for 2013) reported having no formal HR software roadmap, and 40 percent stated that they “did not know” whether their organizations would be increasing their use of cloud or software as a service (SaaS) for HR.  Clearly, HR organizations need help sorting through the morass of HR software options confronting them. But just as clearly, there’s an enormous opportunity awaiting those that do. The trick will come in charting a course that allows HR to leverage existing technology while investing in the cloud-based solutions that will deliver the end-to-end processes, easy-to-understand analytics, and superior adaptability required to simplify—and add value to—every aspect of employee management. The Opportunity therefore is to cut costs, drive Innovation, and increase engagement by moving to cloud-based HCM.  Then you will benefit from one Interface, leverage many access points, and  gain at-a-glance insight across your entire workforce. With many legacy on-premises HR systems not being efficient anymore and cloud-based, integrated systems that span the range of HR functions finally reaching maturity, the time is ripe for moving core HR to the cloud. Indeed, for the first time ever there are more HRMS replacement initiatives than HRMS upgrade initiatives under way, and the majority of them involve moving to the cloud per Cedar Crestone’s 2013-2014 HRMS survey. To learn how you can launch your own cloud HCM initiative and begin using HR to power the enterprise, visit Oracle HRMS in the Cloud and Oracle’s new customer 2 cloud program. Anke Mogannam brings more than 16 years of marketing and human capital management experience in the technology industries to her role at Oracle where she is part of the Human Capital Management applications marketing team. In that role, Anke drives content marketing, messaging, go-to-market activities, integrated marketing campaigns, and field enablement. Prior to joining Oracle, Anke held several roles in communications, marketing, HCM product strategy and product management at PeopleSoft, SAP, Workday and Saba. Follow her on Twitter @amogannam

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• PaaS, DBaaS and the Oracle Database Cloud Service

  - by yaldahhakim

  v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 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:0in; mso-para-margin-bottom:.0001pt; 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; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} As with many widely hyped areas, there is much more variation within the broad spectrum of products referred to as “Cloud” that is immediately apparent. This variation is evident in one of the key misunderstandings about the Oracle Database Cloud Service. People could be forgiven for thinking that the Database Cloud Service was a Database-as-a-Service (DBaaS), but this is actually not true. The Database Cloud Service is a Platform-as-a-Service, which presents a different user and developer interface and has a different set of qualities. A good way to think about the difference between these two varieties of Cloud offerings is that you, the customer, have to deal with things at the level of the offering, but not for anything below it. In practice, this means that you do not have to deal with hardware or system software, including installation and maintenance, for DBaaS. You also do not have much control over configuration of these options. For PaaS, you don’t have to deal with hardware, system software, or database software – and also do not have control over these levels in the stack. So you cannot modify configuration parameters for the database with the Database Cloud Service – your interface is through SQL and PL/SQL, with Application Express, included in the Database Cloud Service, or through JDBC for Java apps running in the Java Cloud Service, or through RESTful Web Services. You will notice what is not mentioned there – SQL*Net. You cannot access your Oracle Database Cloud Service by changing an entry in the TNSNames file and using SQL*Net. So the effort involved in migrating an existing Oracle Database in your data center to the Database Cloud Service may be prohibitive. The good news is that Application Express and the RESTful Web Services wizard in the Database Cloud Service allow you to develop new applications very quickly, and, of course, the provisioning of the entire Database Cloud Service takes only minutes.

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• Musings on the launch of SQL Monitor

  - by Phil Factor

  For several years, I was responsible for the smooth running of a large number of enterprise database servers. We ran a network monitoring tool that was primitive by today’s standards but which performed the useful function of polling every system, including all the Servers in my charge. It ran a configurable script for each service that you needed to monitor that was merely required to return one of a number of integer values. These integer values represented the pain level of the service, from 10 (“hurtin’ real bad”) to 1 (“Things is great”). Not only could you program the visual appearance of each server on the network diagram according to the value of the integer, but you could even opt to run a sound file. Very soon, we had a large TFT Screen, high on the wall of the server room, with every server represented by an icon, and a speaker next to it that would give out a series of grunts, groans, snores, shrieks and funeral marches, depending on the problem. One glance at the display, and you could dive in with iSQL/QA/SSMS and check what was going on with your favourite diagnostic tools. If you saw a server icon burst into flames on the screen or droop like a jelly, you dropped your mug of coffee to do it.  It was real fun, but I remember it more for the huge difference it made to have that real-time visibility into how your servers are performing. The management soon stopped making jokes about the real reason we wanted the TFT screen. (It rendered DVDs beautifully they said; particularly flesh-tints). If you are instantly alerted when things start to go wrong, then there was a good chance you could fix it before being alerted to the problem by the users of the system.  There is a world of difference between this sort of tool, one that gives whoever is ‘on watch’ in the server room the first warning of a potential problem on one of any number of servers, and the breed of tool that attempts to provide some sort of prosthetic DBA Brain. I like to get the early warning, to get the right information to help to diagnose a problem: No auto-fix, but just the information. I prefer to leave the task of ascertaining the exact cause of a problem to my own routines, custom code, intuition and forensic instincts. A simulated aircraft cockpit doesn’t do anything for me, especially before I know where I should be flying.  Time has moved on, and that TFT screen is now, with SQL Monitor, an iPad or any other mobile or static device that can support a browser. Rather than trying to reproduce the conceptual topology of the servers, it lists them in their groups so as to give a display that scales with the increasing number of databases you monitor.  It gives the history of the major events and trends for the servers. It gives the icons and colours that you can spot out of the corner of your eye, but goes on to give you just enough information in drill-down to give you a much clearer idea of where to look with your DBA tools and routines. It doesn't swamp you with information.  Whereas a few server and database-level problems are pretty easily fixed, others depend on judgement and experience to sort out.  Although the idea of an application that automates the bulk of a DBA’s skills is attractive to many, I can’t see it happening soon. SQL Server’s complexity increases faster than the panaceas can be created. In the meantime, I believe that the best way of helping  DBAs  is to make the monitoring process as simple and effective as possible,  and provide the right sort of detail and ‘evidence’ to allow them to decide on the fix. In the end, it is still down to the skill of the DBA.

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• Controlling soft errors and false alarms in SSIS

  - by Jim Giercyk

  If you are like me, you dread the 3AM wake-up call.  I would say that the majority of the pages I get are false alarms.  The alerts that require action often require me to open an SSIS package, see where the trouble is and try to identify the offending data.  That can be very time-consuming and can take quite a chunk out of my beauty sleep.  For those reasons, I have developed a simple error handling scenario for SSIS which allows me to rest a little easier.  Let me first say, this is a high level discussion; getting into the nuts and bolts of creating each shape is outside the scope of this document, but if you have an average understanding of SSIS, you should have no problem following along. In the Data Flow above you can see that there is a caution triangle.  For the purpose of this discussion I am creating a truncation error to demonstrate the process, so this is to be expected.  The first thing we need to do is to redirect the error output.  Double-clicking on the Query shape presents us with the properties window for the input.  Simply set the columns that you want to redirect to Redirect Row in the dropdown box and hit Apply. Without going into a dissertation on error handling, I will just note that you can decide which errors you want to redirect on Error and on Truncation.  Therefore, to override this process for a column or condition, simply do not redirect that column or condition. The next thing we want to do is to add some information about the error; specifically, the name of the package which encountered the error and which step in the package wrote the record to the error table.  REMEMBER: If you redirect the error output, your package will not fail, so you will not know where the error record was created without some additional information.    I added 3 columns to my error record; Severity, Package Name and Step Name.  Severity is just a free-form column that you can use to note whether an error is fatal, whether the package is part of a test job and should be ignored, etc.  Package Name and Step Name are system variables. In my package I have created a truncation situation, where the firstname column is 50 characters in the input, but only 4 characters in the output.  Some records will pass without truncation, others will be sent to the error output.  However, the package will not fail. We can see that of the 14 input rows, 8 were redirected to the error table. This information can be used by another step or another scheduled process or triggered to determine whether an error should be sent.  It can also be used as a historical record of the errors that are encountered over time.  There are other system variables that might make more sense in your infrastructure, so try different things.  Date and time seem like something you would want in your output for example.  In summary, we have redirected the error output from an input, added derived columns with information about the errors, and inserted the information and the offending data into an error table.  The error table information can be used by another step or process to determine, based on the error information, what level alert must be sent.  This will eliminate false alarms, and give you a head start when a genuine error occurs.

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• Simple Merging Of PDF Documents with iTextSharp 5.4.5.0

  - by Mladen Prajdic

  As we were working on our first SQL Saturday in Slovenia, we came to a point when we had to print out the so-called SpeedPASS's for attendees. This SpeedPASS file is a PDF and contains thier raffle, lunch and admission tickets. The problem is we have to download one PDF per attendee and print that out. And printing more than 10 docs at once is a pain. So I decided to make a little console app that would merge multiple PDF files into a single file that would be much easier to print. I used an open source PDF manipulation library called iTextSharp version 5.4.5.0 This is a console program I used. It’s brilliantly named MergeSpeedPASS. It only has two methods and is really short. Don't let the name fool you It can be used to merge any PDF files. The first parameter is the name of the target PDF file that will be created. The second parameter is the directory containing PDF files to be merged into a single file. using iTextSharp.text; using iTextSharp.text.pdf; using System; using System.IO; namespace MergeSpeedPASS { class Program { static void Main(string[] args) { if (args.Length == 0 || args[0] == "-h" || args[0] == "/h") { Console.WriteLine("Welcome to MergeSpeedPASS. Created by Mladen Prajdic. Uses iTextSharp 5.4.5.0."); Console.WriteLine("Tool to create a single SpeedPASS PDF from all downloaded generated PDFs."); Console.WriteLine(""); Console.WriteLine("Example: MergeSpeedPASS.exe targetFileName sourceDir"); Console.WriteLine(" targetFileName = name of the new merged PDF file. Must include .pdf extension."); Console.WriteLine(" sourceDir = path to the dir containing downloaded attendee SpeedPASS PDFs"); Console.WriteLine(""); Console.WriteLine(@"Example: MergeSpeedPASS.exe MergedSpeedPASS.pdf d:\Downloads\SQLSaturdaySpeedPASSFiles"); } else if (args.Length == 2) CreateMergedPDF(args[0], args[1]); Console.WriteLine(""); Console.WriteLine("Press any key to exit..."); Console.Read(); } static void CreateMergedPDF(string targetPDF, string sourceDir) { using (FileStream stream = new FileStream(targetPDF, FileMode.Create)) { Document pdfDoc = new Document(PageSize.A4); PdfCopy pdf = new PdfCopy(pdfDoc, stream); pdfDoc.Open(); var files = Directory.GetFiles(sourceDir); Console.WriteLine("Merging files count: " + files.Length); int i = 1; foreach (string file in files) { Console.WriteLine(i + ". Adding: " + file); pdf.AddDocument(new PdfReader(file)); i++; } if (pdfDoc != null) pdfDoc.Close(); Console.WriteLine("SpeedPASS PDF merge complete."); } } } } Hope it helps you and have fun.

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• Extrapolation breaks collision detection

  - by user22241

  Before applying extrapolation to my sprite's movement, my collision worked perfectly. However, after applying extrapolation to my sprite's movement (to smooth things out), the collision no longer works. This is how things worked before extrapolation: However, after I implement my extrapolation, the collision routine breaks. I am assuming this is because it is acting upon the new coordinate that has been produced by the extrapolation routine (which is situated in my render call ). After I apply my extrapolation How to correct this behaviour? I've tried puting an extra collision check just after extrapolation - this does seem to clear up a lot of the problems but I've ruled this out because putting logic into my rendering is out of the question. I've also tried making a copy of the spritesX position, extrapolating that and drawing using that rather than the original, thus leaving the original intact for the logic to pick up on - this seems a better option, but it still produces some weird effects when colliding with walls. I'm pretty sure this also isn't the correct way to deal with this. I've found a couple of similar questions on here but the answers haven't helped me. This is my extrapolation code: public void onDrawFrame(GL10 gl) { //Set/Re-set loop back to 0 to start counting again loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip){ SceneManager.getInstance().getCurrentScene().updateLogic(); nextGameTick+=skipTicks; timeCorrection += (1000d/ticksPerSecond) % 1; nextGameTick+=timeCorrection; timeCorrection %=1; loops++; tics++; } extrapolation = (float)(System.currentTimeMillis() + skipTicks - nextGameTick) / (float)skipTicks; render(extrapolation); } Applying extrapolation render(float extrapolation){ //This example shows extrapolation for X axis only. Y position (spriteScreenY is assumed to be valid) extrapolatedPosX = spriteGridX+(SpriteXVelocity*dt)*extrapolation; spriteScreenPosX = extrapolationPosX * screenWidth; drawSprite(spriteScreenX, spriteScreenY); } Edit As I mentioned above, I have tried making a copy of the sprite's coordinates specifically to draw with.... this has it's own problems. Firstly, regardless of the copying, when the sprite is moving, it's super-smooth, when it stops, it's wobbling slightly left/right - as it's still extrapolating it's position based on the time. Is this normal behavior and can we 'turn it off' when the sprite stops? I've tried having flags for left / right and only extrapolating if either of these is enabled. I've also tried copying the last and current positions to see if there is any difference. However, as far as collision goes, these don't help. If the user is pressing say, the right button and the sprite is moving right, when it hits a wall, if the user continues to hold the right button down, the sprite will keep animating to the right, while being stopped by the wall (therefore not actually moving), however because the right flag is still set and also because the collision routine is constantly moving the sprite out of the wall, it still appear to the code (not the player) that the sprite is still moving, and therefore extrapolation continues. So what the player would see, is the sprite 'static' (yes, it's animating, but it's not actually moving across the screen), and every now and then it shakes violently as the extrapolation attempts to do it's thing....... Hope this help

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• Library order is important

  - by Darryl Gove

  I've written quite extensively about link ordering issues, but I've not discussed the interaction between archive libraries and shared libraries. So let's take a simple program that calls a maths library function: #include <math.h int main() { for (int i=0; i<10000000; i++) { sin(i); } } We compile and run it to get the following performance: bash-3.2$ cc -g -O fp.c -lm bash-3.2$ timex ./a.out real 6.06 user 6.04 sys 0.01 Now most people will have heard of the optimised maths library which is added by the flag -xlibmopt. This contains optimised versions of key mathematical functions, in this instance, using the library doubles performance: bash-3.2$ cc -g -O -xlibmopt fp.c -lm bash-3.2$ timex ./a.out real 2.70 user 2.69 sys 0.00 The optimised maths library is provided as an archive library (libmopt.a), and the driver adds it to the link line just before the maths library - this causes the linker to pick the definitions provided by the static library in preference to those provided by libm. We can see the processing by asking the compiler to print out the link line: bash-3.2$ cc -### -g -O -xlibmopt fp.c -lm /usr/ccs/bin/ld ... fp.o -lmopt -lm -o a.out... The flag to the linker is -lmopt, and this is placed before the -lm flag. So what happens when the -lm flag is in the wrong place on the command line: bash-3.2$ cc -g -O -xlibmopt -lm fp.c bash-3.2$ timex ./a.out real 6.02 user 6.01 sys 0.01 If the -lm flag is before the source file (or object file for that matter), we get the slower performance from the system maths library. Why's that? If we look at the link line we can see the following ordering: /usr/ccs/bin/ld ... -lmopt -lm fp.o -o a.out So the optimised maths library is still placed before the system maths library, but the object file is placed afterwards. This would be ok if the optimised maths library were a shared library, but it is not - instead it's an archive library, and archive library processing is different - as described in the linker and library guide: "The link-editor searches an archive only to resolve undefined or tentative external references that have previously been encountered." An archive library can only be used resolve symbols that are outstanding at that point in the link processing. When fp.o is placed before the libmopt.a archive library, then the linker has an unresolved symbol defined in fp.o, and it will search the archive library to resolve that symbol. If the archive library is placed before fp.o then there are no unresolved symbols at that point, and so the linker doesn't need to use the archive library. This is why libmopt needs to be placed after the object files on the link line. On the other hand if the linker has observed any shared libraries, then at any point these are checked for any unresolved symbols. The consequence of this is that once the linker "sees" libm it will resolve any symbols it can to that library, and it will not check the archive library to resolve them. This is why libmopt needs to be placed before libm on the link line. This leads to the following order for placing files on the link line: Object files Archive libraries Shared libraries If you use this order, then things will consistently get resolved to the archive libraries rather than to the shared libaries.

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• Grub2 : Windows 7 can't boot installing with Ubuntu 10.04 on different hard drive

  - by dellphi

  I use a dual boot with two hard disks and two OS is Ubuntu 10.04 and Windows 7. Windows 7 installed on the first disk, first partition. Grub is installed on a second hard disk MBR, and Ubuntu installed on an extended partition on a second hard drive. When I select Windows 7 on the Grub menu, the HDD lamp lights up briefly and then black screen on the monitor, with the status of the keyboard is still functioning. Until now (with the default boot from first HDD), I have to press F12 to get into the Grub to run Linux on a second HDD. ================ fdisk -l ================================ dellph1@dellph1-desktop:~$ fdisk -l omitting empty partition (5) Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00087dec Device Boot Start End Blocks Id System /dev/sda1 * 1 23104 185582848+ 7 HPFS/NTFS /dev/sda2 23105 121601 791177122 5 Extended /dev/sda5 36107 74408 307660783+ 7 HPFS/NTFS /dev/sda6 74409 100081 206218341 7 HPFS/NTFS /dev/sda7 100082 121601 172859368+ 7 HPFS/NTFS Disk /dev/sdb: 160.0 GB, 160041885696 bytes 255 heads, 63 sectors/track, 19457 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x6d43dfb2 Device Boot Start End Blocks Id System /dev/sdb1 1 10030 80560066 5 Extended /dev/sdb5 * 1 5560 44657601 83 Linux /dev/sdb6 5560 9387 30736384 83 Linux /dev/sdb7 9387 10030 5164032 82 Linux swap / Solaris dellph1@dellph1-desktop:~$ ================= grub.cfg ================== # DO NOT EDIT THIS FILE # It is automatically generated by /usr/sbin/grub-mkconfig using templates from /etc/grub.d and settings from /etc/default/grub # BEGIN /etc/grub.d/00_header if [ -s $prefix/grubenv ]; then load_env fi set default="0" if [ ${prev_saved_entry} ]; then set saved_entry=${prev_saved_entry} save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z ${boot_once} ]; then saved_entry=${chosen} save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n ${have_grubenv} ]; then if [ -z ${boot_once} ]; then save_env recordfail; fi; fi } insmod ext2 set root='(hd1,5)' search --no-floppy --fs-uuid --set 2f014a3a-35f3-4d05-87aa-34ca677160b7 if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=1024x768 insmod gfxterm insmod vbe if terminal_output gfxterm ; then true ; else # For backward compatibility with versions of terminal.mod that don't # understand terminal_output terminal gfxterm fi fi insmod ext2 set root='(hd1,5)' search --no-floppy --fs-uuid --set 2f014a3a-35f3-4d05-87aa-34ca677160b7 set locale_dir=($root)/boot/grub/locale set lang=en insmod gettext if [ ${recordfail} = 1 ]; then set timeout=-1 else set timeout=5 fi END /etc/grub.d/00_header BEGIN /etc/grub.d/05_debian_theme insmod ext2 set root='(hd1,5)' search --no-floppy --fs-uuid --set 2f014a3a-35f3-4d05-87aa-34ca677160b7 insmod jpeg if background_image /usr/share/backgrounds/CurlsbyCandy.jpg ; then set color_normal=white/black set color_highlight=black/light-gray else set menu_color_normal=white/black set menu_color_highlight=black/light-gray fi END /etc/grub.d/05_debian_theme BEGIN /etc/grub.d/10_linux menuentry 'Ubuntu, with Linux 2.6.32-24-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod ext2 set root='(hd1,5)' search --no-floppy --fs-uuid --set 2f014a3a-35f3-4d05-87aa-34ca677160b7 linux /boot/vmlinuz-2.6.32-24-generic root=UUID=2f014a3a-35f3-4d05-87aa-34ca677160b7 ro splash vga=795 quiet splash nomodeset video=uvesafb:mode_option=1280x1024-24,mtrr=3,scroll=ywrap initrd /boot/initrd.img-2.6.32-24-generic } menuentry 'Ubuntu, with Linux 2.6.32-24-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod ext2 set root='(hd1,5)' search --no-floppy --fs-uuid --set 2f014a3a-35f3-4d05-87aa-34ca677160b7 echo 'Loading Linux 2.6.32-24-generic ...' linux /boot/vmlinuz-2.6.32-24-generic root=UUID=2f014a3a-35f3-4d05-87aa-34ca677160b7 ro single splash vga=795 echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-2.6.32-24-generic } END /etc/grub.d/10_linux BEGIN /etc/grub.d/30_os-prober menuentry "Windows 7 (loader) (on /dev/sda1)" { insmod ntfs set root='(hd0,1)' search --no-floppy --fs-uuid --set 5cac2139ac210f58 chainloader +1 } END /etc/grub.d/30_os-prober BEGIN /etc/grub.d/40_multisystem Ajout de MultiSystem MULTISYSTEM MENU menuentry "PLoP Boot Manager" { linux16 /boot/plpbt } menuentry "Smart Boot Manager" { search --set -f /boot/sbootmgr.dsk linux16 /boot/memdisk initrd16 /boot/sbootmgr.dsk } FIN MULTISYSTEM MENU END /etc/grub.d/40_multisystem ================================================ I want to keep the Grub on the second HDD. I have been using the Startup Manager, Boot Manager and Grub Customizer, and this problem still unsolved. The easiest thing that I can possibly do is to install Grub on first HDD, but I was curious and maybe someone can help.

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• Learn Many Languages

  - by Jeff Foster

  My previous blog, Deliberate Practice, discussed the need for developers to “sharpen their pencil” continually, by setting aside time to learn how to tackle problems in different ways. However, the Sapir-Whorf hypothesis, a contested and somewhat-controversial concept from language theory, seems to hold reasonably true when applied to programming languages. It states that: “The structure of a language affects the ways in which its speakers conceptualize their world.” If you’re constrained by a single programming language, the one that dominates your day job, then you only have the tools of that language at your disposal to think about and solve a problem. For example, if you’ve only ever worked with Java, you would never think of passing a function to a method. A good developer needs to learn many languages. You may never deploy them in production, you may never ship code with them, but by learning a new language, you’ll have new ideas that will transfer to your current “day-job” language. With the abundant choices in programming languages, how does one choose which to learn? Alan Perlis sums it up best. “A language that doesn‘t affect the way you think about programming is not worth knowing“ With that in mind, here’s a selection of languages that I think are worth learning and that have certainly changed the way I think about tackling programming problems. Clojure Clojure is a Lisp-based language running on the Java Virtual Machine. The unique property of Lisp is homoiconicity, which means that a Lisp program is a Lisp data structure, and vice-versa. Since we can treat Lisp programs as Lisp data structures, we can write our code generation in the same style as our code. This gives Lisp a uniquely powerful macro system, and makes it ideal for implementing domain specific languages. Clojure also makes software transactional memory a first-class citizen, giving us a new approach to concurrency and dealing with the problems of shared state. Haskell Haskell is a strongly typed, functional programming language. Haskell’s type system is far richer than C# or Java, and allows us to push more of our application logic to compile-time safety. If it compiles, it usually works! Haskell is also a lazy language – we can work with infinite data structures. For example, in a board game we can generate the complete game tree, even if there are billions of possibilities, because the values are computed only as they are needed. Erlang Erlang is a functional language with a strong emphasis on reliability. Erlang’s approach to concurrency uses message passing instead of shared variables, with strong support from both the language itself and the virtual machine. Processes are extremely lightweight, and garbage collection doesn’t require all processes to be paused at the same time, making it feasible for a single program to use millions of processes at once, all without the mental overhead of managing shared state. The Benefits of Multilingualism By studying new languages, even if you won’t ever get the chance to use them in production, you will find yourself open to new ideas and ways of coding in your main language. For example, studying Haskell has taught me that you can do so much more with types and has changed my programming style in C#. A type represents some state a program should have, and a type should not be able to represent an invalid state. I often find myself refactoring methods like this… void SomeMethod(bool doThis, bool doThat) { if (!(doThis ^ doThat)) throw new ArgumentException(“At least one arg should be true”); if (doThis) DoThis(); if (doThat) DoThat(); } …into a type-based solution, like this: enum Action { DoThis, DoThat, Both }; void SomeMethod(Action action) { if (action == Action.DoThis || action == Action.Both) DoThis(); if (action == Action.DoThat || action == Action.Both) DoThat(); } At this point, I’ve removed the runtime exception in favor of a compile-time check. This is a trivial example, but is just one of many ideas that I’ve taken from one language and implemented in another.

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• Know your Data Lineage

  - by Simon Elliston Ball

  An academic paper without the footnotes isn’t an academic paper. Journalists wouldn’t base a news article on facts that they can’t verify. So why would anyone publish reports without being able to say where the data has come from and be confident of its quality, in other words, without knowing its lineage. (sometimes referred to as ‘provenance’ or ‘pedigree’) The number and variety of data sources, both traditional and new, increases inexorably. Data comes clean or dirty, processed or raw, unimpeachable or entirely fabricated. On its journey to our report, from its source, the data can travel through a network of interconnected pipes, passing through numerous distinct systems, each managed by different people. At each point along the pipeline, it can be changed, filtered, aggregated and combined. When the data finally emerges, how can we be sure that it is right? How can we be certain that no part of the data collection was based on incorrect assumptions, that key data points haven’t been left out, or that the sources are good? Even when we’re using data science to give us an approximate or probable answer, we cannot have any confidence in the results without confidence in the data from which it came. You need to know what has been done to your data, where it came from, and who is responsible for each stage of the analysis. This information represents your data lineage; it is your stack-trace. If you’re an analyst, suspicious of a number, it tells you why the number is there and how it got there. If you’re a developer, working on a pipeline, it provides the context you need to track down the bug. If you’re a manager, or an auditor, it lets you know the right things are being done. Lineage tracking is part of good data governance. Most audit and lineage systems require you to buy into their whole structure. If you are using Hadoop for your data storage and processing, then tools like Falcon allow you to track lineage, as long as you are using Falcon to write and run the pipeline. It can mean learning a new way of running your jobs (or using some sort of proxy), and even a distinct way of writing your queries. Other Hadoop tools provide a lot of operational and audit information, spread throughout the many logs produced by Hive, Sqoop, MapReduce and all the various moving parts that make up the eco-system. To get a full picture of what’s going on in your Hadoop system you need to capture both Falcon lineage and the data-exhaust of other tools that Falcon can’t orchestrate. However, the problem is bigger even that that. Often, Hadoop is just one piece in a larger processing workflow. The next step of the challenge is how you bind together the lineage metadata describing what happened before and after Hadoop, where ‘after’ could be  a data analysis environment like R, an application, or even directly into an end-user tool such as Tableau or Excel. One possibility is to push as much as you can of your key analytics into Hadoop, but would you give up the power, and familiarity of your existing tools in return for a reliable way of tracking lineage? Lineage and auditing should work consistently, automatically and quietly, allowing users to access their data with any tool they require to use. The real solution, therefore, is to create a consistent method by which to bring lineage data from these data various disparate sources into the data analysis platform that you use, rather than being forced to use the tool that manages the pipeline for the lineage and a different tool for the data analysis. The key is to keep your logs, keep your audit data, from every source, bring them together and use the data analysis tools to trace the paths from raw data to the answer that data analysis provides.

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• The battle between Java vs. C#

  The battle between Java vs. C# has been a big debate amongst the development community over the last few years. Both languages have specific pros and cons based on the needs of a particular project. In general both languages utilize a similar coding syntax that is based on C++, and offer developers similar functionality. This being said, the communities supporting each of these languages are very different. The divide amongst the communities is much like the political divide in America, where the Java community would represent the Democrats and the .Net community would represent the Republicans. The Democratic Party is a proponent of the working class and the general population. Currently, Java is deeply entrenched in the open source community that is distributed freely to anyone who has an interest in using it. Open source communities rely on developers to keep it alive by constantly contributing code to make applications better; essentially they develop code by the community. This is in stark contrast to the C# community that is typically a pay to play community meaning that you must pay for code that you want to use because it is developed as products to be marketed and sold for a profit. This ties back into my reference to the Republicans because they typically represent the needs of business and personal responsibility. This is emphasized by the belief that code is a commodity and that it can be sold for a profit which is in direct conflict to the laissez-faire beliefs of the open source community. Beyond the general differences between Java and C#, they also target two different environments. Java is developed to be environment independent and only requires that users have a Java virtual machine running in order for the java code to execute. C# on the other hand typically targets any system running a windows operating system and has the appropriate version of the .Net Framework installed. However, recently there has been push by a segment of the Open source community based around the Mono project that lets C# code run on other non-windows operating systems. In addition, another feature of C# is that it compiles into an intermediate language, and this is what is executed when the program runs. Because C# is reduced down to an intermediate language called Common Language Runtime (CLR) it can be combined with other languages that are also compiled in to the CLR like Visual Basic (VB) .Net, and F#. The allowance and interaction between multiple languages in the .Net Framework enables projects to utilize existing code bases regardless of the actual syntax because they can be compiled in to CLR and executed as one codebase. As a software engineer I personally feel that it is really important to learn as many languages as you can or at least be open to learn as many languages as you can because no one language will work in every situation.  In some cases Java may be a better choice for a project and others may be C#. It really depends on the requirements of a project and the time constraints. In addition, I feel that is really important to concentrate on understanding the logic of programming and be able to translate business requirements into technical requirements. If you can understand both programming logic and business requirements then deciding which language to use is just basically choosing what syntax to write for a given business problem or need. In regards to code refactoring and dynamic languages it really does not matter. Eventually all projects will be refactored or decommissioned to allow for progress. This is the way of life in the software development industry. The language of a project should not be chosen based on the fact that a project will eventually be refactored because they all will get refactored.

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• Why bother writing an Windows 8 app?

  - by Dennis Vroegop

  So you want to know more about development for Window 8. Great! There are lots of reasons you should be excited about this. Since I don’t know why YOU are interested in this, I’ll make a list of reasons people can choose from. (as a side note: whenever I talk about Win8 development I am referring to the Metro Style / WinRt side of things. Apps for the ‘classic’ desktop side of Win8 on Intel are business as usual…) So… Why would you care about making an app for Windows 8? 1. It’s cool. Let’s not beat around the bush: if you like development for a hobby then you’ll love to work on this new platform. You can create apps in a relative short time (short time as in compared to writing a new CRM system) and that makes it great for a hobby product. 2. You’ll stand out. Hey, we all need an ego boost every now and then. We all need to feel special. So if you can manage to be one of the first to have you app in the Store then you’ll likely to be noticed. Just close your eyes for a moment and image you standing in a bar. It’s crowded, and then you casually say “Oh yeah, I just had my app certified and it’s in the Win8 store now”. People will stop talking, will offer you drinks and beautiful women / gorgeous man / furry creatures from Alpha Centauri (whatever your preferences are) will propose. Or maybe not. Anyway…. 3. Make some cash! IDC predicts there will be about 350,000,000 Windows 8 licenses sold in the next year. Think about that number. 350,000,000. And they all have access to the Store. Where you’re app will be. With one little click they can select it, download and somehow magically $1.00 or $2.00 from their bank account is transferred to yours. Now, I am not saying that all of those people will download and buy your app but what if only 1% of them did? Remember: there aren’t that many apps available yet….. 4. Learn. Creating new small apps is a great way to learn new stuff. Yes, you could read about it (on this blog for instance) but the only way to learn something is to do it. So be prepared for the future and learn something new by doing it.Write an app! Now! 5. The biggie (for me at least): it’s fun. Even if you remove the points above it’s still fun to write for these devices and this platform. Now some of you will say : “But why not write a great app for IOS or Android?” I think this is a valid question. Of course the novelty of the platform wears out and points 2 and 3 from above list will not be as relevant as it is today. But still 1 4 and 5 remain. And don’t forget: if you already work on the Microsoft platform it’s not that hard to learn this new Win8 stuff. If you have done some XAML development (be it WPF or Silverlight) you are almost there in becoming a good Win8 developer. So you’ll be more productive much sooner than when you have to learn Objective C or Java. Even if you’re a HTML / Javascript developer (I say developer here, not designer) you’ll be up to speed on Win8 development pretty soon. Yes, you, that funky Web Developer who lives and breathes HTML5, CSS3 and JavaScript / Node.Js / JQuery: you too can be a Win8 developer. A first class Win8 developer! So.. Download the stuff you need from http://dev.windows.com install Windows 8 and Visual Studio 12 and by the time you’re ready I’ll be working on the next article: how to do all this? Happy coding!

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• I am trying to figure out the best way to understand how to cache domain objects

  - by Brett Ryan

  I've always done this wrong, I'm sure a lot of others have too, hold a reference via a map and write through to DB etc.. I need to do this right, and I just don't know how to go about it. I know how I want my objects to be cached but not sure on how to achieve it. What complicates things is that I need to do this for a legacy system where the DB can change without notice to my application. So in the context of a web application, let's say I have a WidgetService which has several methods: Widget getWidget(); Collection<Widget> getAllWidgets(); Collection<Widget> getWidgetsByCategory(String categoryCode); Collection<Widget> getWidgetsByContainer(Integer parentContainer); Collection<Widget> getWidgetsByStatus(String status); Given this, I could decide to cache by method signature, i.e. getWidgetsByCategory("AA") would have a single cache entry, or I could cache widgets individually, which would be difficult I believe; OR, a call to any method would then first cache ALL widgets with a call to getAllWidgets() but getAllWidgets() would produce caches that match all the keys for the other method invocations. For example, take the following untested theoretical code. Collection<Widget> getAllWidgets() { Entity entity = cache.get("ALL_WIDGETS"); Collection<Widget> res; if (entity == null) { res = loadCache(); } else { res = (Collection<Widget>) entity.getValue(); } return res } Collection<Widget> loadCache() { // Get widgets from underlying DB Collection<Widget> res = db.getAllWidgets(); cache.put("ALL_WIDGETS", res); Map<String, List<Widget>> byCat = new HashMap<>(); for (Widget w : res) { // cache by different types of method calls, i.e. by category if (!byCat.containsKey(widget.getCategory()) { byCat.put(widget.getCategory(), new ArrayList<Widget>); } byCat.get(widget.getCatgory(), widget); } cacheCategories(byCat); return res; } Collection<Widget> getWidgetsByCategory(String categoryCode) { CategoryCacheKey key = new CategoryCacheKey(categoryCode); Entity ent = cache.get(key); if (entity == null) { loadCache(); } ent = cache.get(key); return ent == null ? Collections.emptyList() : (Collection<Widget>)ent.getValue(); } NOTE: I have not worked with a cache manager, the above code illustrates cache as some object that may hold caches by key/value pairs, though it's not modelled on any specific implementation. Using this I have the benefit of being able to cache all objects in the different ways they will be called with only single objects on the heap, whereas if I were to cache the method call invocation via say Spring It would (I believe) cache multiple copies of the objects. I really wish to try and understand the best ways to cache domain objects before I go down the wrong path and make it harder for myself later. I have read the documentation on the Ehcache website and found various articles of interest, but nothing to give a good solid technique. Since I'm working with an ERP system, some DB calls are very complicated, not that the DB is slow, but the business representation of the domain objects makes it very clumsy, coupled with the fact that there are actually 11 different DB's where information can be contained that this application is consolidating in a single view, this makes caching quite important.

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• Subterranean IL: Exception handling 2

  - by Simon Cooper

  Control flow in and around exception handlers is tightly controlled, due to the various ways the handler blocks can be executed. To start off with, I'll describe what SEH does when an exception is thrown. Handling exceptions When an exception is thrown, the CLR stops program execution at the throw statement and searches up the call stack looking for an appropriate handler; catch clauses are analyzed, and filter blocks are executed (I'll be looking at filter blocks in a later post). Then, when an appropriate catch or filter handler is found, the stack is unwound to that handler, executing successive finally and fault handlers in their own stack contexts along the way, and program execution continues at the start of the catch handler. Because catch, fault, finally and filter blocks can be executed essentially out of the blue by the SEH mechanism, without any reference to preceding instructions, you can't use arbitary branches in and out of exception handler blocks. Instead, you need to use specific instructions for control flow out of handler blocks: leave, endfinally/endfault, and endfilter. Exception handler control flow try blocks You cannot branch into or out of a try block or its handler using normal control flow instructions. The only way of entering a try block is by either falling through from preceding instructions, or by branching to the first instruction in the block. Once you are inside a try block, you can only leave it by throwing an exception or using the leave <label> instruction to jump to somewhere outside the block and its handler. The leave instructions signals the CLR to execute any finally handlers around the block. Most importantly, you cannot fall out of the block, and you cannot use a ret to return from the containing method (unlike in C#); you have to use leave to branch to a ret elsewhere in the method. As a side effect, leave empties the stack. catch blocks The only way of entering a catch block is if it is run by the SEH. At the start of the block execution, the thrown exception will be the only thing on the stack. The only way of leaving a catch block is to use throw, rethrow, or leave, in a similar way to try blocks. However, one thing you can do is use a leave to branch back to an arbitary place in the handler's try block! In other words, you can do this: .try { // ... newobj instance void [mscorlib]System.Exception::.ctor() throw MidTry: // ... leave.s RestOfMethod } catch [mscorlib]System.Exception { // ... leave.s MidTry } RestOfMethod: // ... As far as I know, this mechanism is not exposed in C# or VB. finally/fault blocks The only way of entering a finally or fault block is via the SEH, either as the result of a leave instruction in the corresponding try block, or as part of handling an exception. The only way to leave a finally or fault block is to use endfinally or endfault (both compile to the same binary representation), which continues execution after the finally/fault block, or, if the block was executed as part of handling an exception, signals that the SEH can continue walking the stack. filter blocks I'll be covering filters in a separate blog posts. They're quite different to the others, and have their own special semantics. Phew! Complicated stuff, but it's important to know if you're writing or outputting exception handlers in IL. Dealing with the C# compiler is probably best saved for the next post.

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• WF4 &ndash; Guess the number game!

  - by MarkPearl

  I posted yesterday how really good WF4 was looking. Today I thought I would show some real basics that I was able to figure out. This will be a simple example, I am going to make a flowchart workflow – which will prompt the user to guess the number until they guess the right number. Lets begin… Make a new project and make it a Workflow console Application. Then select the Workflow file and drag a FlowChart (2) to point 3. This will now show a green start circle in the designer form. We are going to work with primitives to start with. We are now going to drag a few objects onto the Workflow, We drag the WriteLine, Assign & Decision items onto the designer. Once they are dragged onto the designer we will want to link them up. The order that they are linked is critical since this will determine the order of the solution. In this case, we want the system to first ask “Guess a number”, then to wait for the user to input some code, and then to display “You got it” if they got it right, and “Try again” if they got it wrong. So we now link the arrows to the objects. This is done by moving the mouse pointer over the start objects and clicking on one of the toggles and then dragging it to the next object and releasing the button over one of the toggles. This will place an arrow from the source object to the target object. Okay… pretty simple stuff – now we just need these primitive objects to do stuff. Lets start with the WriteLine primitive. We place the text in inverted commas in the Text field. Because this field accepts any valid VB expression we could have put variables etc. in there if we wanted to. The next thing we want to do is allow the user to input a number. This brings up an interesting problem, if a user were to type in a number, there would need to be someway to declare a variable to hold that value for the life of the workflow. We can achieve this by declaring a variable. To declare a variable, move your cursor over the variables tab at the bottom of the workflow, and then type the name of the new variable in the “Create Variable” field and set it as shown in the image above. Now that we have a variable, we want to call the Console.Readline method and assign the inputted value from the Console to that variable. The code that cannot be seen is actually this – Convert.ToInt32(Console.ReadLine()) We now have a workflow that first prompts the user for a number, then allows the user to type in a number. We are almost done, we just need to make the system react to the value inputted. There are a few ways we could do this, I am going to use the Decision item. So select the Decision object on the designer and then view its properties (F4 for me), and in the condition field place a condition. For simplicity sake I have decided that if the user guesses 10, they will have guessed the number. This is now the completed workflow. Its really easy to understand and shows some really powerful principles for Business applications. You can run the application and see what it does. Imagine writing business solutions that do not worry about the exact flow of objects, but simply allows a business analyst or someone to configure the solution to work exactly as the business rules would dictate. And if the rules changed six months later all they would need to do is re-drag some of the flows. Now I do not know if WF4 will allow for this, but it feels like it is a step in the right direct.

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