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• Is it an good idea to make a wrapper specifically for a DateTime that respresents Now?

  - by Dirk Boer

  I have been noticing lately that is really nice to use a DateTime representing 'now' as an input parameter for your methods, for mocking and testing purposes. Instead of every method calling DateTime.UtcNow themselves, I do it once in the upper methods and forward it on the lower ones. So a lot of methods that need a 'now', have an input parameter DateTime now. (I'm using MVC, and try to detect a parameter called now and modelbind DateTime.UtcNow to it) So instead of: public bool IsStarted { get { return StartTime >= DateTime.UtcNow; } } I usually have: public bool IsStarted(DateTime now) { return StartTime >= now; } So my convention is at the moment, if a method has a DateTime parameter called now, you have to feed it with the current time. Of course this comes down to convention, and someone else can easily just throw some other DateTime in there as a parameter. To make it more solid and static-typed I am thinking about wrapping DateTime in a new object, i.e. DateTimeNow. So in one of the most upper layers I will convert the DateTime to a DateTimeNow and we will get compile errors when, someone tries to fiddle in a normal DateTime. Of course you can still workaround this, but at least if feels more that you are doing something wrong at point. Did anyone else ever went into this path? Are there any good or bad results on the long term that I am not thinking about?

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• CoffeeScript 2 Dimensional Array Usage

  - by Chris

  I feel like I'm missing something with CoffeeScript and 2 dimensional arrays. I'm simply attempting to make a grid of spaces (think checkers). After some searching and a discovery with the arrays.map function, I came up with this: @spaces = [0...20].map (x)-> [0...20].map (y) -> new Elements.Space() And this seems to work great, I have a nice 2 dimensional array with my Space object created in each. But now I want to send the created space constructor the x,y location. Because I'm two layers deep, I lost the x variable when I entered the map function for y. Ideally I would want to do something like: @spaces = [0...20].map (x)-> [0...20].map (y) -> new Elements.Space(x, y) or something that feels more natural to me like: for row in rows for column in row @spaces[row][column] = new Elements.Space(row, column) I'm really open to any better way of doing this. I know how I would do it in standard JavaScript, but really would like to learn how to do it in CoffeeScript.

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• Call c++ library from c#

  - by Batul

  Hello All, This question might seem a repeat of previous ones. I have read through a series of posts, but not completely clear for my situation. I have a c++ library which is created using momentics IDE. I have to be able to use this library into a c# project. Someone had been working on this project before being handed over to me. Currently, there are 2 layers for making this possible. First, a c++ project includes the complete library with a c++ wrapper. This project creates a dll as the output. This c++ dll is then fed to a c# project, which has dllimport calls to the c++ dll. This c# project again creates a dll. Finally, in order to use the library in c# application, I have to include a reference to both of these dlls. Is this the correct way to get it working? I was thinking probably there should be a way to simplify the process. Can someone please help me with this question?

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• Image switch based on if a layer is visible

  - by Zuno

  I have a website that contains multiple pages as layers (not as separate HTML files). I have three images: <img src="image1.png" onclick="showlayer(1);return false;" /> <br /> <img src="image2.png" onclick="showlayer(2);return false;" /> <br /> <img src="image3.png" onclick="showlayer(3);return false;" /> When an image is clicked, it shows the relevant layer and hides the others. I want it to also change the image to image1_active.png / image2_active.png / image3_active.png depending on which layer is visible (not via the onclick event handler). Why not via the onclick event handler?... Layer 1 is set as visible by default in the CSS, so image1 needs to be image1_active.png by default too - since the user has not had to click on anything yet, this is why I need the image switch to detect the layer's visibility/display to change the image. The showlayer script is: function showlayer(n){ for(i=1;i<=3;i++){document.getElementById("layer"+i).style.display="none";document.getElementById("layer"+n).style.display="block"; }} Is it possible to adapt this script for this purpose? thank you

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• Best available technology for layered disk cache in linux

  - by SpliFF

  I've just bought a 6-core Phenom with 16G of RAM. I use it primarily for compiling and video encoding (and occassional web/db). I'm finding all activities get disk-bound and I just can't keep all 6 cores fed. I'm buying an SSD raid to sit between the HDD and tmpfs. I want to setup a "layered" filesystem where reads are cached on tmpfs but writes safely go through to the SSD. I want files (or blocks) that haven't been read lately on the SSD to then be written back to a HDD using a compressed FS or block layer. So basically reads: - Check tmpfs - Check SSD - Check HD And writes: - Straight to SSD (for safety), then tmpfs (for speed) And periodically, or when space gets low: - Move least frequently accessed files down one layer. I've seen a few projects of interest. CacheFS, cachefsd, bcache seem pretty close but I'm having trouble determining which are practical. bcache seems a little risky (early adoption), cachefs seems tied to specific network filesystems. There are "union" projects unionfs and aufs that let you mount filesystems over each other (USB device over a DVD usually) but both are distributed as a patch and I get the impression this sort of "transparent" mounting was going to become a kernel feature rather than a FS. I know the kernel has a built-in disk cache but it doesn't seem to work well with compiling. I see a 20x speed improvement when I move my source files to tmpfs. I think it's because the standard buffers are dedicated to a specific process and compiling creates and destroys thousands of processes during a build (just guessing there). It looks like I really want those files precached. I've read tmpfs can use virtual memory. In that case is it practical to create a giant tmpfs with swap on the SSD? I don't need to boot off the resulting layered filesystem. I can load grub, kernel and initrd from elsewhere if needed. So that's the background. The question has several components I guess: Recommended FS and/or block layer for the SSD and compressed HDD. Recommended mkfs parameters (block size, options etc...) Recommended cache/mount technology to bind the layers transparently Required mount parameters Required kernel options / patches, etc..

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• How to change radius of rounded rectangle in Photoshop

  - by MattDiPasquale

  At this point, I'm thinking of just using CSS 3, esp. since I'm a programmer, but I'd like to do this with Photoshop because I think it's nicer since I'm working with images anyway, among other reasons... Before I move on, my first question is: Is there a place like SuperUser for designers (or for Photoshop-like or questions)? What I Want: I want the icons on http://www.mattdipasquale.com/ to look like those on http://about.me/mattdipasquale. About.me has an outdated Twitter icon and does not have icons for GitHub, StackOverflow, etc. So, although I like the look of their icons, I want to be able to create these icons myself instead of using their versions. What I Have: I have different iphone icons, like the Facebook iPhone icon, Twitter iPhone icon, etc., that I got from iTunes, using Firebug to find the URL of the background image. I opened them up in Photoshop and pressed option + command + i to reduce the image size to 32px x 32px with Bicubic Sharper (best for reduction). I now have a square icon layer. Closing the Gap: In addition to the icon layer, I want to have a clipping-mask layer that will apply the 5px rounded-corners, 1px stroke, and 1px bevel. (Note: I just want to apply effects to the edges of the icon because the gloss and other effects are already encoded in the iTunes image. Also, I'm just guessing about the pixel values, but I want it to look good, like the icons on about.me.) What settings should I use for the blend options to make the icons look good, like iphone icons or those used by about.me? Why a Clipping Mask? The reason I want to use a clipping mask is that I want ease of reproducibility. I want to be able to apply the same styling to other square icon layers by simply replacing the square icon layer and then saving for web. If there is a better way to achieve such ease of reproducibility, please suggest it. I've seen Photoshop iPhone icon templates, but I couldn't figure out how to use them with my own images. Thanks! Matt

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• Is dual-booting an OS more or less secure than running a virtual machine?

  - by Mark

  I run two operating systems on two separate disk partitions on the same physical machine (a modern MacBook Pro). In order to isolate them from each other, I've taken the following steps: Configured /etc/fstab with ro,noauto (read-only, no auto-mount) Fully encrypted each partition with a separate encryption key (committed to memory) Let's assume that a virus infects my first partition unbeknownst to me. I log out of the first partition (which encrypts the volume), and then turn off the machine to clear the RAM. I then un-encrypt and boot into the second partition. Can I be reasonably confident that the virus has not / cannot infect both partitions, or am I playing with fire here? I realize that MBPs don't ship with a TPM, so a boot-loader infection going unnoticed is still a theoretical possibility. However, this risk seems about equal to the risk of the VMWare/VirtualBox Hypervisor being exploited when running a guest OS, especially since the MBP line uses UEFI instead of BIOS. This leads to my question: is the dual-partitioning approach outlined above more or less secure than using a Virtual Machine for isolation of services? Would that change if my computer had a TPM installed? Background: Note that I am of course taking all the usual additional precautions, such as checking for OS software updates daily, not logging in as an Admin user unless absolutely necessary, running real-time antivirus programs on both partitions, running a host-based firewall, monitoring outgoing network connections, etc. My question is really a public check to see if I'm overlooking anything here and try to figure out if my dual-boot scheme actually is more secure than the Virtual Machine route. Most importantly, I'm just looking to learn more about security issues. EDIT #1: As pointed out in the comments, the scenario is a bit on the paranoid side for my particular use-case. But think about people who may be in corporate or government settings and are considering using a Virtual Machine to run services or applications that are considered "high risk". Are they better off using a VM or a dual-boot scenario as I outlined? An answer that effectively weighs any pros/cons to that trade-off is what I'm really looking for in an answer to this post. EDIT #2: This question was partially fueled by debate about whether a Virtual Machine actually protects a host OS at all. Personally, I think it does, but consider this quote from Theo de Raadt on the OpenBSD mailing list: x86 virtualization is about basically placing another nearly full kernel, full of new bugs, on top of a nasty x86 architecture which barely has correct page protection. Then running your operating system on the other side of this brand new pile of shit. You are absolutely deluded, if not stupid, if you think that a worldwide collection of software engineers who can't write operating systems or applications without security holes, can then turn around and suddenly write virtualization layers without security holes. -http://kerneltrap.org/OpenBSD/Virtualization_Security By quoting Theo's argument, I'm not endorsing it. I'm simply pointing out that there are multiple perspectives here, so I'm trying to find out more about the issue.

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• The Koyal Group Info Mag News¦Charged building material could make the renewable grid a reality

  - by Chyler Tilton

  What if your cell phone didn’t come with a battery? Imagine, instead, if the material from which your phone was built was a battery. The promise of strong load-bearing materials that can also work as batteries represents something of a holy grail for engineers. And in a letter published online in Nano Letters last week, a team of researchers from Vanderbilt University describes what it says is a breakthrough in turning that dream into an electrocharged reality. The researchers etched nanopores into silicon layers, which were infused with a polyethylene oxide-ionic liquid composite and coated with an atomically thin layer of carbon. In doing so, they created small but strong supercapacitor battery systems, which stored electricity in a solid electrolyte, instead of using corrosive chemical liquids found in traditional batteries. These supercapacitors could store and release about 98 percent of the energy that was used to charge them, and they held onto their charges even as they were squashed and stretched at pressures up to 44 pounds per square inch. Small pieces of them were even strong enough to hang a laptop from—a big, fat Dell, no less. Although the supercapacitors resemble small charcoal wafers, they could theoretically be molded into just about any shape, including a cell phone’s casing or the chassis of a sedan. They could also be charged—and evacuated of their charge—in less time than is the case for traditional batteries. “We’ve demonstrated, for the first time, the simple proof-of-concept that this can be done,” says Cary Pint, an assistant professor in the university’s mechanical engineering department and one of the authors of the new paper. “Now we can extend this to all kinds of different materials systems to make practical composites with materials specifically tailored to a host of different types of applications. We see this as being just the tip of a very massive iceberg.” Pint says potential applications for such materials would go well beyond “neat tech gadgets,” eventually becoming a “transformational technology” in everything from rocket ships to sedans to home building materials. “These types of systems could range in size from electric powered aircraft all the way down to little tiny flying robots, where adding an extra on-board battery inhibits the potential capability of the system,” Pint says. And they could help the world shift to the intermittencies of renewable energy power grids, where powerful batteries are needed to help keep the lights on when the sun is down or when the wind is not blowing. “Using the materials that make up a home as the native platform for energy storage to complement intermittent resources could also open the door to improve the prospects for solar energy on the U.S. grid,” Pint says. “I personally believe that these types of multifunctional materials are critical to a sustainable electric grid system that integrates solar energy as a key power source.”

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• Holding off Windows 2000/3 Server in Shutdown

  - by user1668993

  We have a C# VS2010 application running on a Windows 2000 Server box (there is also a Windows 2003 Server box) as pretty much the only application running. We remove power from the box. There is a short duration battery (maybe 3 minutes of power) which then waits 10 seconds and then decides things are coming down and notifies Windows that it needs to shut down. Windows sends a CTRL_SHUTDOWN_EVENT event to the application which fields it and tries to keep Windows from going down for a while to let another computer which communicates with this one time to do some file work on the first computer. It does this by a timing loop and after the loop is over, it exits gracefully and the computer shuts down. Nice plan but it doesn't work. The application gets to maybe 20 seconds and the application is forcibly killed by Windows and Windows shuts down. At 90 seconds, the hardware firmware running the battery turns off power to the computer. I have tried searching to find out how to hold off Windows for a bit of time. I tried creating (it wasn't there) the HKEY_LOCAL_MACHINE subtree: \SYSTEM\CurrentControlSet\Control\WaitToKillAppTimeout registry key to 60000 but though it seemed to keep the popup from happening, Windows itself died at about the same amount of time -- we think without having the opportunity to shut itself down gracefully. Maybe the registry key worked but wasn't enough. Basically I have an "ill-mannered" application which is refusing to shut down (for the best of reasons) and without the registry key thing, Windows eventually shuts it down anyway and then shuts itself down. With the registry change, we think what is happening is that Windows doesn't shut down the application but Windows itself is killed suddenly without shutting down but power is still not pulled for about another minute, and then power is pulled. So maybe we have layers here. First there is how long the application tries to stay open. Then there is how long Windows is prepared to allow it to stay open. Then there is ... something... which kills windows. Then there is the power loss. Anyone have any ideas how we can get windows to stay open and in operation say to 70 seconds instead of about 20? Is our registry key right, but not enough? Is there some additional key we need to set to determine how long after windows is notified of a shutdown before it just kills itself? Thanks in advance.

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• Adobe Photoshop Vs Lightroom Vs Aperture

  - by Aditi

  Adobe Photoshop is the standard choice for photographers, graphic artists and Web designers. Adobe Photoshop Lightroom  & Apple’s Aperture are also in the same league but the usage is vastly different. Although Photoshop is most popular & widely used by photographers, but in many ways it’s less relevant to photographers than ever before. As Lightroom & Aperture is aimed squarely at photographers for photo-processing. With this write up we are going to help you choose what is right for you and why. Adobe Photoshop Adobe Photoshop is the most liked tool for the detailed photo editing & designing work. Photoshop provides great features for rollover and Image slicing. Adobe Photoshop includes comprehensive optimization features for producing the highest quality Web graphics with the smallest possible file sizes. You can also create startling animations with it. Designers & Editors know how important precise masking is, PhotoShop lets you do that with various detailing tools. Art history brush, contact sheets, and history palette are some of the smart features, which add to its viability. Download Whether you’re producing printed pages or moving images, you can work more efficiently and produce better results because of its smooth integration across other adobe applications. Buy supporting layer effects, it allows you to quickly add drop shadows, inner and outer glows, bevels, and embossing to layers. It also provides Seamless Web Graphics Workflow. Photoshop is hands-down the BEST for editing. Photoshop Cons: • Slower, less precise editing features in Bridge • Processing lots of images requires actions and can be slower than exporting images from Lightroom • Much slower with editing and processing a large number of images Aperture Apple Aperture is aimed at the professional photographer who shoots predominantly raw files. It helps them to manage their workflow and perform their initial Raw conversion in a better way. Aperture provides adjustment tools such as Histogram to modify color and white balance, but most of the editing of photos is left for Photoshop. It gives users the option of seeing their photographs laid out like slides or negatives on a light table. It boasts of – stars, color-coding and easy techniques for filtering and picking images. Aperture has moved forward few steps than Photoshop, but most of the editing work has been left for Photoshop as it features seamless Photoshop integration. Aperture Pros: Aperture is a step up from the iPhoto software that comes with every Mac, and fairly easy to learn. Adjustments are made in a logical order from top to bottom of the menu. You can store the images in a library or any folder you choose. Aperture also works really well with direct Canon files. It is just $79 if you buy it through Apple’s App Store Moving forward, it will run on the iPad, and possibly the iPhone – Adobe products like Lightroom and Photoshop may never offer these options It is much nicer and simpler user interface. Lightroom Lightroom does a smashing job of basic fixing and editing. It is more advanced tool for photographers. They can use it to have a startling photography effect. Light room has many advanced features, which makes it one of the best tools for photographers and far ahead of the other two. They are Nondestructive editing. Nothing is actually changed in an image until the photo is exported. Better controls over organizing your photos. Lightroom helps to gather a group of photos to use in a slideshow. Lightroom has larger Compare and Survey views of images. Quickly customizable interface. Simple keystrokes allow you to perform different All Lightroom controls are kept available in panels right next to the photos. Always-available History palette, it doesn’t go when you close lightroom. You gain more colors to work with compared to Photoshop and with more precise control. Local control, or adjusting small parts of a photo without affecting anything else, has long been an important part of photography. In Lightroom 2, you can darken, lighten, and affect color and change sharpness and other aspects of specific areas in the photo simply by brushing your cursor across the areas. Photoshop has far more power in its Cloning and Healing Brush tools than Lightroom, but Lightroom offers simple cloning and healing that’s nondestructive. Lightroom supports the RAW formats of more cameras than Aperture. Lightroom provides the option of storing images outside the application in the file system. It costs less than photoshop. Download Why PhotoShop is advanced than Lightroom? There are countless image processing plug-ins on the market for doing specialized processing in Photoshop. For example, if your image needs sophisticated noise reduction, you can use the Noiseware plug-in with Photoshop to do a much better job or noise removal than Lightroom can do. Lightroom’s advantages over Aperture 3 Will always have better integration with Photoshop. Lightroom is backed by bigger and more active user community (So abundant availability for tutorials, etc.) Better noise reduction tool. Especially for photographers the Lens-distortion correction tool  is perfect Lightroom Cons: • Have to Import images to work on them • Slows down with over 10,000 images in the catalog • For processing just one or two images this is a slower workflow Photoshop Pros: • ACR has the same RAW processing controls as Lightroom • ACR Histogram is specialized to the chosen color space (Lightroom is locked into ProPhoto RGB color space with an sRGB tone curve) • Don’t have to Import images to open in Bridge or ACR • Ability to customize processing of RAW images with Photoshop Actions Pricing and Availability Get LightRoomGet PhotoShop Latest version Of Photoshop can be purchased from Adobe store and Adobe authorized reseller and it costs US$999. Latest version of Aperture can be bought for US$199 from Apple Online store or Mac App Store. You can buy latest version of LightRoom from Adobe Store or Adobe Authorized reseller for US$299. Related posts:Adobe Photoshop CS5 vs Photoshop CS5 extended Web based Alternatives to Photoshop 10 Free Alternatives for Adobe Photoshop Software

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• ODI and OBIEE 11g Integration

  - by David Allan

  Here we will see some of the connectivity options to OBIEE 11g using the JDBC driver. You’ll see based upon some connection properties how the physical or presentation layers can be utilized. In the integrators guide for OBIEE 11g you will find a brief statement indicating that there actually is a JDBC driver for OBIEE. In OBIEE 11g its now possible to connect directly to the physical layer, Venkat has an informative post here on this topic. In ODI 11g the Oracle BI technology is shipped with the product along with KMs for reverse engineering, and using OBIEE models for a data source. When you install OBIEE in 11g a light weight demonstration application is preinstalled in the server, when you open this in the BI Administration tool we see the regular 3 panel view within the administration tool. To interrogate this system via JDBC (just like ODI does using the KMs) need a couple of things; the JDBC driver from OBIEE 11g, a java client program and the credentials. In my java client program I want to connect to the OBIEE system, when I connect I can interrogate what the JDBC driver presents for the metadata. The metadata projected via the JDBC connection’s DatabaseMetadata changes depending on whether the property NQ_SESSION.SELECTPHYSICAL is set when the java client connects. Let’s use the sample app to illustrate. I have a java client program here that will print out the tables in the DatabaseMetadata, it will also output the catalog and schema. For example if I execute without any special JDBC properties as follows; java -classpath .;%BIHOMEDIR%\clients\bijdbc.jar meta_jdbc oracle.bi.jdbc.AnaJdbcDriver jdbc:oraclebi://localhost:9703/ weblogic mypass Then I get the following returned representing the presentation layer, the sample I used is XML, and has no schema; Catalog Schema Table Sample Sales Lite null Base Facts Sample Sales Lite null Calculated Facts …     Sample Targets Lite null Base Facts …     Now if I execute with the only difference being the JDBC property NQ_SESSION.SELECTPHYSICAL with the value Yes, then I see a different set of values representing the physical layer in OBIEE; java -classpath .;%BIHOMEDIR%\clients\bijdbc.jar meta_jdbc oracle.bi.jdbc.AnaJdbcDriver jdbc:oraclebi://localhost:9703/ weblogic mypass NQ_SESSION.SELECTPHYSICAL=Yes The following is returned; Catalog Schema Table Sample App Lite Data null D01 Time Day Grain Sample App Lite Data null F10 Revenue Facts (Order grain) …     System DB (Update me)     …     If this was a database system such as Oracle, the catalog value would be the OBIEE database name and the schema would be the Oracle database schema. Other systems which have real catalog structure such as SQLServer would use its catalog value. Its this ‘Catalog’ and ‘Schema’ value that is important when integration OBIEE with ODI. For the demonstration application in OBIEE 11g, the following illustration shows how the information from OBIEE is related via the JDBC driver through to ODI. In the XML example above, within ODI’s physical schema definition on the right, we leave the schema blank since the XML data source has no schema. When I did this at first, I left the default value that ODI places in the Schema field since which was ‘<Undefined>’ (like image below) but this string is actually used in the RKM so ended up not finding any tables in this schema! Entering an empty string resolved this. Below we see a regular Oracle database example that has the database, schema, physical table structure, and how this is defined in ODI.   Remember back to the physical versus presentation layer usage when we passed the special property, well to do this in ODI, the data server has a panel for properties where you can define key/value pairs. So if you want to select physical objects from the OBIEE server, then you must set this property. An additional changed in ODI 11g is the OBIEE connection pool support, this has been implemented via a ‘Connection Pool’ flex field for the Oracle BI data server. So here you set the connection pool name from the OBIEE system that you specifically want to use and this is used by the Oracle BI to Oracle (DBLINK) LKM, so if you are using this you must set this flex field. Hopefully a useful insight into some of the mechanics of how this hangs together.

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• Book Review: Oracle ADF Real World Developer’s Guide

  - by Frank Nimphius

  Recently PACKT Publishing published "Oracle ADF Real World Developer’s Guide" by Jobinesh Purushothaman, a product manager in our team. Though already the sixth book dedicated to Oracle ADF, it has a lot of great information in it that none of the previous books covered, making it a safe buy even for those who own the other books published by Oracle Press (McGrwHill) and PACKT Publishing. More than the half of the "Oracle ADF Real World Developer’s Guide" book is dedicated to Oracle ADF Business Components in a depth and clarity that allows you to feel the expertise that Jobinesh gained in this area. If you enjoy Jobinesh blog (http://jobinesh.blogspot.co.uk/) about Oracle ADF, then, no matter what expert you are in Oracle ADF, this book makes you happy as it provides you with detail information you always wished to have. If you are new to Oracle ADF, then this book alone doesn't get you flying, but, if you have some Java background, accelerates your learning big, big, big times. Chapter 1 is an introduction to Oracle ADF and not only explains the layers but also how it compares to plain Java EE solutions (page 13). If you are new to Oracle JDeveloper and ADF, then at the end of this chapter you know how to start JDeveloper and begin your ADF development Chapter 2 starts with what Jobinesh really is good at: ADF Business Components. In this chapter you learn about the architecture ingredients of ADF Business Components: View Objects, View Links, Associations, Entities, Row Sets, Query Collections and Application Modules. This chapter also provides a introduction to ADFBC SDO services, as well as sequence diagrams for what happens when you execute queries or commit updates. Chapter 3 is dedicated to entity objects and  is one of many chapters in this book you will enjoy and never want to miss. Jobinesh explains the artifacts that make up an entity object, how to work with entities and resource bundles, and many advanced topics, including inheritance, change history tracking, custom properties, validation and cursor handling.  Chapter 4 - you guessed it - is all about View objects. Comparable to entities, you learn about the XM files and classes that make a view object, as well as how to define and work with queries. List-of-values, inheritance, polymorphism, bind variables and data filtering are interesting - and important topics that follow. Again the chapter provides helpful sequence diagrams for you to understand what happens internally within a view object. Chapter 5 focuses on advanced view object and entity object topics, like lifecycle callback methods and when you want to override them. This chapter is a good digest of Jobinesh's blog entries (which most ADF developers have in their bookmark list). Really worth reading ! Chapter 6 then is bout Application Modules. Beside of what application modules are, this chapter covers important topics like properties, passivation, activation, application module pooling, how and where to write custom logic. In addition you learn about the AM lifecycle and request sequence. Chapter 7 is about the ADF binding layer. If you are new to Oracle ADF and got lost in the more advanced ADF Business Components chapters, then this chapter is where you get back into the game. In very easy terms, Jobinesh explains what the ADF binding is, how it fits into the JSF request lifecycle and what are the metadata file involved. Chapter 8 then goes into building data bound web user interfaces. In this chapter you get the basics of JavaServer Faces (e.g. managed beans) and learn about the interaction between the JSF UI and the ADF binding layer. Later this chapter provides advanced solutions for working with tree components and list of values. Chapter 9 introduces bounded task flows and ADF controller. This is a chapter you want to read if you are new to ADF of have started. Experts don't find anything new here, which doesn't mean that it is not worth reading it (I for example, enjoyed the controller talk very much) Chapter 10 is an advanced coverage of bounded task flow and talks about contextual events  Chapter 11 is another highlight and explains error handling, trains, transactions and more. I can only recommend you read this chapter. I am aware of many documents that cover exception handling in Oracle ADF (and my Oracle Magazine article for January/February 2013 does the same), but none that covers it in such a great depth. Chapter 12 covers ADF best practices, which is a great round-up of all the tips provided in this book (without Jobinesh to repeat himself). Its all cool stuff that helps you with your ADF projects. In summary, "Oracle ADF Real World Developer’s Guide" by Jobinesh Purushothaman is a great book and addition for all Oracle ADF developers and those who want to become one. Frank

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• Building a Distributed Commerce Infrastructure in the Cloud using Azure and Commerce Server

  - by Lewis Benge

  One of the biggest questions I routinely get asked is how scalable Commerce Server is. Of course the text book answer is the product has been around for 10 years, powers some of the largest e-Commerce websites in the world, so it scales horizontally extremely well. One argument however though is what if you can't predict the growth of demand required of your Commerce Platform, or need the ability to scale up during busy seasons such as Christmas for a retail environment but are hesitant on maintaining the infrastructure on a year-round basis? The obvious answer is to utilise the many elasticated cloud infrastructure providers that are establishing themselves in the ever-growing market, the problem however is Commerce Server is still product which has a legacy tightly coupled dependency on Windows and IIS components. Commerce Server 2009 codename "R2" however introduced to the concept of an n-tier deployment of Microsoft Commerce Server, meaning you are no longer tied to core objects API but instead have serializable Commerce Entity objects, and business logic allowing for Commerce Server to now be built into a WCF-based SOA architecture. Presentation layers no-longer now need to remain on the same physical machine as the application server, meaning you can now build the user experience into multiple-technologies and host them in multiple places – leveraging the transport benefits that a WCF service may bring, such as message queuing, security, and multiple end-points. All of this logic will still need to remain in your internal infrastructure, for two reasons. Firstly cloud based computing infrastructure does not support PCI security requirements, and secondly even though many of the legacy Commerce Server dependencies have been abstracted away within this version of the application, it is still not a fully supported to be deployed exclusively into the cloud. If you do wish to benefit from the scalability of the cloud however, you can still achieve a great Commerce Server and Azure setup by utilising both the Azure App Fabric in terms of the service bus, and authentication services and Windows Azure to host any online presence you may require. The architecture would be something similar to this: This setup would allow you to construct your Commerce Services as part of your on-site infrastructure. These services would contain all of the channels custom business logic, and provide the overall interface back into the underlying Commerce Server components. It would be recommended that services are constructed around the specific business domain of the application, which based on your business model would usually consist of separate services around Catalogue, Orders, Search, Profiles, and Marketing. The App Fabric service bus is then used to abstract and aggregate further the services, making them available to the cloud and subsequently secured by App Fabrics authentication services. These services are now available for consumption by any client, using any supported technology – not just .NET. Thus meaning you are now able to construct apps for IPhone, integrate with Java based POS Devices, and any many other potential uses. This aggregation is useful, and forms the basis of the further strategy around diversifying and enhancing the e-Commerce experience, but also provides the foundation for the scalability we want to gain from utilising a cloud-based application platform. The Windows Azure application platform is Microsoft solution to benefiting from the true economies of scale in terms of the elasticity of the cloud. Just before the launch of the Azure Platform – Domino's pizza actually managed to run their whole SuperBowl operation from the scalability of Windows Azure, and simply switching back to their traditional operation the next day with no residual infrastructure costs. The platform also natively can subscribe to services and messages exposed within the AppFabric service bus, making it an ideal solution to build and deploy a presentation layer which will need to support of scalable infrastructure – such as a high demand public facing e-Commerce portal, or a promotion element of a brand. Windows Azure has excellent support for ASP.NET, including its own caching providers meaning expensive operations such as catalogue queries can persist in memory on the application server, reducing the demand on internal infrastructure and prioritising it for more business critical operations such as receiving orders and processing payments. Windows Azure also supports other languages too, meaning utilising this approach you can technically build a Commerce Server presentation layer in Java, PHP, or Ruby – or equally in ASP.NET or Silverlight without having to change any of the underlying business or Commerce Server implementation. This SOA-style architecture is one of the primary differentiators for Commerce Server as a product in the e-Commerce market, and now with the introduction of a WCF capability in Commerce Server 2009/2009 R2 the opportunities for extensibility of the both the user experience, and integration into third parties, are drastically increased, all with no effect to the underlying channel logic. So if you are looking at deployment options for your e-Commerce application to help support demand in a cost effective way. I would highly recommend you consider looking at Windows Azure, and if you have any questions in-particular about this style of deployment, please feel free to get in touch!

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• Simple Excel Export with EPPlus

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/10/30/simple-excel-export-with-epplus.aspxAnyone I’ve ever met who works with an application that sits in front of a lot of data loves it when they can get that data exported to an Excel file for them to mess around with offline. As both developer and end user of a little website project that I’ve been working on, I found myself wanting to be able to get a bunch of the data that the application was collecting into an Excel file. The great thing about being both an end user and a developer on a project is that you can build the features that you really want! While putting this feature together I came across the fantastic EPPlus library. This library is certainly very well known and popular, but I was so impressed with it that I thought it was worth a quick blog post. This library is extremely powerful; it lets you create and manipulate Excel 2007/2010 spreadsheets in .NET code with a high degree of flexibility. My only gripe with the project is that they are not touting how insanely easy it is to build a basic Excel workbook from a simple data source. If I were running this project the approach I’m about to demonstrate in this post would be front and center on the landing page for the project because it shows how easy it really is to get started and serves as a good way to ease yourself in to some of the more advanced features. The website in question uses RavenDB, which means that we’re dealing with POCOs to model the data throughout all layers of the application. I love working like this so when it came time to figure out how to export some of this data to an Excel spreadsheet I wanted to find a way to take an IEnumerable<T> and just have it dumped to Excel with each item in the collection being modeled as a single row in the Excel worksheet. Consider the following class: public class Employee { public int Id { get; set; } public string Name { get; set; } public decimal HourlyRate { get; set; } public DateTime HireDate { get; set; } } Now let’s say we have a collection of these represented as an IEnumerable<Employee> and we want to be able to output it to an Excel file for offline querying/manipulation. As it turns out, this is dead simple to do with EPPlus. Have a look: public void ExportToExcel(IEnumerable<Employee> employees, FileInfo targetFile) { using (var excelFile = new ExcelPackage(targetFile)) { var worksheet = excelFile.Workbook.Worksheets.Add("Sheet1"); worksheet.Cells["A1"].LoadFromCollection(Collection: employees, PrintHeaders: true); excelFile.Save(); } } That’s it. Let’s break down what’s going on here: Create a ExcelPackage to model the workbook (Excel file). Note that the ‘targetFile’ value here is a FileInfo object representing the location on disk where I want the file to be saved. Create a worksheet within the workbook. Get a reference to the top-leftmost cell (addressed as A1) and invoke the ‘LoadFromCollection’ method, passing it our collection of Employee objects. Behind the scenes this is reflecting over the properties of the type provided and pulling out any public members to become columns in the resulting Excel output. The ‘PrintHeaders’ parameter tells EPPlus to grab the name of the property and put it in the first row. Save the Excel file All of the heavy lifting here is being done by the ‘LoadFromCollection’ method, and that’s a good thing. Now, this was really easy to do, but it has some limitations. Using this approach you get a very plain, un-styled Excel worksheet. The column widths are all set to the default. The number format for all cells is ‘General’ (which proves particularly interesting if you have a DateTime property in your data source). I’m a “no frills” guy, so I wasn’t bothered at all by trading off simplicity for style and formatting. That said, EPPlus has tons of samples that you can download that illustrate how to apply styles and formatting to cells and a ton of other advanced features that are way beyond the scope of this post.

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• An Alphabet of Eponymous Aphorisms, Programming Paradigms, Software Sayings, Annoying Alliteration

  - by Brian Schroer

  Malcolm Anderson blogged about “Einstein’s Razor” yesterday, which reminded me of my favorite software development “law”, the name of which I can never remember. It took much Wikipedia-ing to find it (Hofstadter’s Law – see below), but along the way I compiled the following list: Amara’s Law: We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run. Brook’s Law: Adding manpower to a late software project makes it later. Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from magic. Law of Demeter: Each unit should only talk to its friends; don't talk to strangers. Einstein’s Razor: “Make things as simple as possible, but not simpler” is the popular paraphrase, but what he actually said was “It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience”, an overly complicated quote which is an obvious violation of Einstein’s Razor. (You can tell by looking at a picture of Einstein that the dude was hardly an expert on razors or other grooming apparati.) Finagle's Law of Dynamic Negatives: Anything that can go wrong, will—at the worst possible moment. - O'Toole's Corollary: The perversity of the Universe tends towards a maximum. Greenspun's Tenth Rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. (Morris’s Corollary: “…including Common Lisp”) Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law. Issawi’s Omelet Analogy: One cannot make an omelet without breaking eggs - but it is amazing how many eggs one can break without making a decent omelet. Jackson’s Rules of Optimization: Rule 1: Don't do it. Rule 2 (for experts only): Don't do it yet. Kaner’s Caveat: A program which perfectly meets a lousy specification is a lousy program. Liskov Substitution Principle (paraphrased): Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it Mason’s Maxim: Since human beings themselves are not fully debugged yet, there will be bugs in your code no matter what you do. Nils-Peter Nelson’s Nil I/O Rule: The fastest I/O is no I/O.    Occam's Razor: The simplest explanation is usually the correct one. Parkinson’s Law: Work expands so as to fill the time available for its completion. Quentin Tarantino’s Pie Principle: “…you want to go home have a drink and go and eat pie and talk about it.” (OK, he was talking about movies, not software, but I couldn’t find a “Q” quote about software. And wouldn’t it be cool to write a program so great that the users want to eat pie and talk about it?) Raymond’s Rule: Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.  Sowa's Law of Standards: Whenever a major organization develops a new system as an official standard for X, the primary result is the widespread adoption of some simpler system as a de facto standard for X. Turing’s Tenet: We shall do a much better programming job, provided we approach the task with a full appreciation of its tremendous difficulty, provided that we respect the intrinsic limitations of the human mind and approach the task as very humble programmers.  Udi Dahan’s Race Condition Rule: If you think you have a race condition, you don’t understand the domain well enough. These rules didn’t exist in the age of paper, there is no reason for them to exist in the age of computers. When you have race conditions, go back to the business and find out actual rules. Van Vleck’s Kvetching: We know about as much about software quality problems as they knew about the Black Plague in the 1600s. We've seen the victims' agonies and helped burn the corpses. We don't know what causes it; we don't really know if there is only one disease. We just suffer -- and keep pouring our sewage into our water supply. Wheeler’s Law: All problems in computer science can be solved by another level of indirection... Except for the problem of too many layers of indirection. Wheeler also said “Compatibility means deliberately repeating other people's mistakes.”. The Wrong Road Rule of Mr. X (anonymous): No matter how far down the wrong road you've gone, turn back. Yourdon’s Rule of Two Feet: If you think your management doesn't know what it's doing or that your organisation turns out low-quality software crap that embarrasses you, then leave. Zawinski's Law of Software Envelopment: Every program attempts to expand until it can read mail. Zawinski is also responsible for “Some people, when confronted with a problem, think 'I know, I'll use regular expressions.' Now they have two problems.” He once commented about X Windows widget toolkits: “Using these toolkits is like trying to make a bookshelf out of mashed potatoes.”

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• XNA Notes 002

  - by George Clingerman

  This past week (much like every week in the XNA community) was filled with things happening and people doing cool things (and getting noticed for doing cool things!). You can definitely tell there are some Xbox LIVE Indie game developers starting to make some names for themselves. Can’t wait to name drop them at bars. Me- “Oh you played Game X? Yeah, I know the guy that made that. Pretty cool guy.” Yeah, I’ll be THAT guy.   Time Critical XNA News 30 days left to submit XBLIGs made in XNA Game Studio 3.1 http://blogs.msdn.com/b/xna/archive/2011/01/08/30-days-left-to-submit-xna-gs-3-1-games-to-app-hub.aspx Jeromy Walsh wants you to know his XNA 4.0 Winter Workshop starting soon, go get signed up! And the forum is now LIVE on GameDev.net http://gamedevelopedia.com/ http://tinyurl.com/4gg2cfv The XNA Team Per Nick Gravelyn, Aaron Stebner’s blog post is a must read for icons on Windows Phone http://forums.create.msdn.com/forums/p/72022/439597.aspx#439597 http://blogs.msdn.com/b/astebner/archive/2010/10/01/10070507.aspx Shawn Hargreaves writes about Sprite Billboards in a 3D world http://blogs.msdn.com/b/shawnhar/archive/2011/01/12/spritebatch-billboards-in-a-3d-world.aspx XNA MVPs Andy “The ZMan” Dunn wants YOU to come to the MVP Summit and run a 5K http://www.indiegameguy.com/blogs/zman/archive/2010/12/26/come-to-the-mvp-summit-and-run-a-5k-yes-you.aspx Jim Perry updates his forum signature just to make it clear that he’s not speaking for Microsoft or giving official information (LOL, thanks Jim, now if only people will take the time to read that...) XNA MVP | Please use the Forum Search and read the Forum FAQs | My posts are not official info http://forums.create.msdn.com/forums/p/70849/439613.aspx#439613 XNA Developers Robert Boyd (@werezombie) working hard at converting his RPG engine used to make Breath of Death VII and Chtulu Saves the World to XNA 4.0. If you haven’t done the upgrade yet yourself, might be useful to read back through his tweets and recent forum posts to see the problems/solutions he’s encountered. http://forums.create.msdn.com/forums/p/71834/438099.aspx#438099 http://www.twitter.com/werezompire SpynDoctorGames is in the final phase before the release of Your Doodles are Bugged for the PC! Going to be interesting to watch as more XNA game developers explore the PC game market for their games. http://twitter.com/SpynDoctorGames/statuses/24503173217521664 http://www.spyn-doctor.de @DrMistry shares some details of his next title YoYoYo http://www.mstargames.co.uk/mistryblogmain/35-genblog/177-a-new-year-a-new-game-and-maybe-a-new-approach.html Travis Woodward (@RabidLionGames) has a blog post coming this weekend on Farseer and Mario-like platformer movement. http://twitter.com/RabidLionGames/statuses/24992762021548032 http://www.rabidlion.com/ S4G Interview with Radiangames http://n4g.com/news/679492/s4g-interview-with-radiangames XBLAratings.com interviews Steve Flores (@DragonDivide) developer of Alpha Squad http://www.xblaratings.com/developer-qaa/3621-alpha-squad-developer-interview XBox LIVE Indie Games If you haven’t been reading the roundups on IndieGames by NaviFairy on GayGamer, you’ve been missing out! http://gaygamer.net/2011/01/xbox_indie_review_roundup_1112.html Armless Octopus posts the Top 20 Games of 2010 Part 1 http://www.armlessoctopus.com/2011/01/10/top-20-xbox-live-indie-games-of-2010-part-1/ Armless Octopus posts the Top 20 Games of 2010 Part 2 http://www.armlessoctopus.com/2011/01/12/top-20-xbox-live-indie-games-of-2010-%E2%80%93-part-2/ Xbox LIVE Indie Game Reviews http://www.gamemarx.com/ Don’t forget to be following @XboxHornet . That’s a great way to snag free copies of Xbox LIVE Indie Games http://twitter.com/XboxHornet/statuses/24471103808208896 http://www.xboxhornet.com/wordpress/ Xbox LIVE Indie Game Review posts the top 20 Xbox 360 LIVE Indie Games of 2010 http://www.xbox-360-community-games-reviews.com/top-20-best-xbox-360-live-indie-games-of-2010/ VVGtv to Stream #XBLIG Again! Help out if you can. http://vvgtv.com/2011/01/07/vvgtv-to-stream-xblig-again/ Indie Gamer Magazine Issue 14 has a look at the Xbox LIVE Winter Indie Game Uprisiing http://www.indiegamemag.com/issue14/ XNA Game Development Andrew Russell announced and asked for help in his development of ExEn: XNA for iPhone, Android and Silverlight http://rockethub.com/projects/752-exen-xna-for-iphone-android-and-silverlight App Hub forums letting you down? Don’t forget about StackOverflow and the game development specific version gamedev.stackexchange http://stackoverflow.com/questions/tagged/xna http://gamedev.stackexchange.com/questions/tagged/xna Transmute gets an update from Aaron Foley (@slyprid) and you can now add and visually edit parallax layers to your 2D tile game. http://twitpic.com/3nudj0 http://twitter.com/slyprid/statuses/23418379574448128 http://forgottenstarstudios.com/Transmute/default.html Webcomics Weekly #75 touches on some feelings I’ve seen people try to express (myself included) when talking about game development and what types of games should be released for XBLIG http://www.pvponline.com/2011/01/05/webcomics-weekly-75-sour-oats/ Setting up a new PC for XNA development? Here’s a site that helps you quickly build a installer for all the most common applications developers use. http://ninite.com/ Fun wew thread on the XNA forums asking XBLIG/XNA developers just what their Top 10 favorite video games of all time are. http://forums.create.msdn.com/forums/107.aspx Christopher Hill (@Xalterax) stumbled across an entire community that does nothing but create box art. This is a great potential resource for Xbox LIVE Indie Game developers to get some awesome box art for their games. http://forums.create.msdn.com/forums/p/46582/441451.aspx#441451 http://www.vgboxart.com/browse/plat/360/ Don’t forget about the XNA Wiki, fantastic community resource (and roll up those sleeves and contribute already!) http://xnawiki.com/index.php?title=Main_Page

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• Big Data – Buzz Words: What is Hadoop – Day 6 of 21

  - by Pinal Dave

  In yesterday’s blog post we learned what is NoSQL. In this article we will take a quick look at one of the four most important buzz words which goes around Big Data – Hadoop. What is Hadoop? Apache Hadoop is an open-source, free and Java based software framework offers a powerful distributed platform to store and manage Big Data. It is licensed under an Apache V2 license. It runs applications on large clusters of commodity hardware and it processes thousands of terabytes of data on thousands of the nodes. Hadoop is inspired from Google’s MapReduce and Google File System (GFS) papers. The major advantage of Hadoop framework is that it provides reliability and high availability. What are the core components of Hadoop? There are two major components of the Hadoop framework and both fo them does two of the important task for it. Hadoop MapReduce is the method to split a larger data problem into smaller chunk and distribute it to many different commodity servers. Each server have their own set of resources and they have processed them locally. Once the commodity server has processed the data they send it back collectively to main server. This is effectively a process where we process large data effectively and efficiently. (We will understand this in tomorrow’s blog post). Hadoop Distributed File System (HDFS) is a virtual file system. There is a big difference between any other file system and Hadoop. When we move a file on HDFS, it is automatically split into many small pieces. These small chunks of the file are replicated and stored on other servers (usually 3) for the fault tolerance or high availability. (We will understand this in the day after tomorrow’s blog post). Besides above two core components Hadoop project also contains following modules as well. Hadoop Common: Common utilities for the other Hadoop modules Hadoop Yarn: A framework for job scheduling and cluster resource management There are a few other projects (like Pig, Hive) related to above Hadoop as well which we will gradually explore in later blog posts. A Multi-node Hadoop Cluster Architecture Now let us quickly see the architecture of the a multi-node Hadoop cluster. A small Hadoop cluster includes a single master node and multiple worker or slave node. As discussed earlier, the entire cluster contains two layers. One of the layer of MapReduce Layer and another is of HDFC Layer. Each of these layer have its own relevant component. The master node consists of a JobTracker, TaskTracker, NameNode and DataNode. A slave or worker node consists of a DataNode and TaskTracker. It is also possible that slave node or worker node is only data or compute node. The matter of the fact that is the key feature of the Hadoop. In this introductory blog post we will stop here while describing the architecture of Hadoop. In a future blog post of this 31 day series we will explore various components of Hadoop Architecture in Detail. Why Use Hadoop? There are many advantages of using Hadoop. Let me quickly list them over here: Robust and Scalable – We can add new nodes as needed as well modify them. Affordable and Cost Effective – We do not need any special hardware for running Hadoop. We can just use commodity server. Adaptive and Flexible – Hadoop is built keeping in mind that it will handle structured and unstructured data. Highly Available and Fault Tolerant – When a node fails, the Hadoop framework automatically fails over to another node. Why Hadoop is named as Hadoop? In year 2005 Hadoop was created by Doug Cutting and Mike Cafarella while working at Yahoo. Doug Cutting named Hadoop after his son’s toy elephant. Tomorrow In tomorrow’s blog post we will discuss Buzz Word – MapReduce. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• What should you bring to the table as a Software Architect?

  - by Ahmad Mageed

  There have been many questions with good answers about the role of a Software Architect (SA) on StackOverflow and Programmers SE. I am trying to ask a slightly more focused question than those. The very definition of a SA is broad so for the sake of this question let's define a SA as follows: A Software Architect guides the overall design of a project, gets involved with coding efforts, conducts code reviews, and selects the technologies to be used. In other words, I am not talking about managerial rest and vest at the crest (further rhyming words elided) types of SAs. If I were to pursue any type of SA position I don't want to be away from coding. I might sacrifice some time to interface with clients and Business Analysts etc., but I am still technically involved and I'm not just aware of what's going on through meetings. With these points in mind, what should a SA bring to the table? Should they come in with a mentality of "laying down the law" (so to speak) and enforcing the usage of certain tools to fit "their way," i.e., coding guidelines, source control, patterns, UML documentation, etc.? Or should they specify initial direction and strategy then be laid back and jump in as needed to correct the ship's direction? Depending on the organization this might not work. An SA who relies on TFS to enforce everything may struggle to implement their plan at an employer that only uses StarTeam. Similarly, an SA needs to be flexible depending on the stage of the project. If it's a fresh project they have more choices, whereas they might have less for existing projects. Here are some SA stories I have experienced as a way of sharing some background in hopes that answers to my questions might also shed some light on these issues: I've worked with an SA who code reviewed literally every single line of code of the team. The SA would do this for not just our project but other projects in the organization (imagine the time spent on this). At first it was useful to enforce certain standards, but later it became crippling. FxCop was how the SA would find issues. Don't get me wrong, it was a good way to teach junior developers and force them to think of the consequences of their chosen approach, but for senior developers it was seen as somewhat draconian. One particular SA was against the use of a certain library, claiming it was slow. This forced us to write tons of code to achieve things differently while the other library would've saved us a lot of time. Fast forward to the last month of the project and the clients were complaining about performance. The only solution was to change certain functionality to use the originally ignored approach despite early warnings from the devs. By that point a lot of code was thrown out and not reusable, leading to overtime and stress. Sadly the estimates used for the project were based on the old approach which my project was forbidden from using so it wasn't an appropriate indicator for estimation. I would hear the PM say "we've done this before," when in reality they had not since we were using a new library and the devs working on it were not the same devs used on the old project. The SA who would enforce the usage of DTOs, DOs, BOs, Service layers and so on for all projects. New devs had to learn this architecture and the SA adamantly enforced usage guidelines. Exceptions to usage guidelines were made when it was absolutely difficult to follow the guidelines. The SA was grounded in their approach. Classes for DTOs and all CRUD operations were generated via CodeSmith and database schemas were another similar ball of wax. However, having used this setup everywhere, the SA was not open to new technologies such as LINQ to SQL or Entity Framework. I am not using this post as a platform for venting. There were positive and negative aspects to my experiences with the SA stories mentioned above. My questions boil down to: What should an SA bring to the table? How can they strike a balance in their decision making? Should one approach an SA job (as defined earlier) with the mentality that they must enforce certain ground rules? Anything else to consider? Thanks! I'm sure these job tasks are easily extended to people who are senior devs or technical leads, so feel free to answer at that capacity as well.

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• College Courses through distance learning

  - by Matt

  I realize this isn't really a programming question, but didn't really know where to post this in the stackexchange and because I am a computer science major i thought id ask here. This is pretty unique to the programmer community since my degree is about 95% programming. I have 1 semester left, but i work full time. I would like to finish up in December, but to make things easier i like to take online classes whenever I can. So, my question is does anyone know of any colleges that offer distance learning courses for computer science? I have been searching around and found a few potential classes, but not sure yet. I would like to gather some classes and see what i can get approval for. Class I need: Only need one C SC 437 Geometric Algorithms C SC 445 Algorithms C SC 473 Automata Only need one C SC 452 Operating Systems C SC 453 Compilers/Systems Software While i only need of each of the above courses i still need to take two more electives. These also have to be upper 400 level classes. So i can take multiple in each category. Some other classes I can take are: CSC 447 - Green Computing CSC 425 - Computer Networking CSC 460 - Database Design CSC 466 - Computer Security I hoping to take one or two of these courses over the summer. If not, then online over the regular semester would be ok too. Any help in helping find these classes would be awesome. Maybe you went to a college that offered distance learning. Some of these classes may be considered to be graduate courses too. Descriptions are listed below if you need. Thanks! Descriptions Computer Security This is an introductory course covering the fundamentals of computer security. In particular, the course will cover basic concepts of computer security such as threat models and security policies, and will show how these concepts apply to specific areas such as communication security, software security, operating systems security, network security, web security, and hardware-based security. Computer Networking Theory and practice of computer networks, emphasizing the principles underlying the design of network software and the role of the communications system in distributed computing. Topics include routing, flow and congestion control, end-to-end protocols, and multicast. Database Design Functions of a database system. Data modeling and logical database design. Query languages and query optimization. Efficient data storage and access. Database access through standalone and web applications. Green Computing This course covers fundamental principles of energy management faced by designers of hardware, operating systems, and data centers. We will explore basic energy management option in individual components such as CPUs, network interfaces, hard drives, memory. We will further present the energy management policies at the operating system level that consider performance vs. energy saving tradeoffs. Finally we will consider large scale data centers where energy management is done at multiple layers from individual components in the system to shutting down entries subset of machines. We will also discuss energy generation and delivery and well as cooling issues in large data centers. Compilers/Systems Software Basic concepts of compilation and related systems software. Topics include lexical analysis, parsing, semantic analysis, code generation; assemblers, loaders, linkers; debuggers. Operating Systems Concepts of modern operating systems; concurrent processes; process synchronization and communication; resource allocation; kernels; deadlock; memory management; file systems. Algorithms Introduction to the design and analysis of algorithms: basic analysis techniques (asymptotics, sums, recurrences); basic design techniques (divide and conquer, dynamic programming, greedy, amortization); acquiring an algorithm repertoire (sorting, median finding, strong components, spanning trees, shortest paths, maximum flow, string matching); and handling intractability (approximation algorithms, branch and bound). Automata Introduction to models of computation (finite automata, pushdown automata, Turing machines), representations of languages (regular expressions, context-free grammars), and the basic hierarchy of languages (regular, context-free, decidable, and undecidable languages). Geometric Algorithms The study of algorithms for geometric objects, using a computational geometry approach, with an emphasis on applications for graphics, VLSI, GIS, robotics, and sensor networks. Topics may include the representation and overlaying of maps, finding nearest neighbors, solving linear programming problems, and searching geometric databases.

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• MDM for Tax Authorities

  - by david.butler(at)oracle.com

  In last week’s MDM blog, we discussed MDM in the Public Sector. I want to continue that thread. After all, no industry faces tougher data quality problems than governmental organizations, and few industries suffer more significant down side consequences to poor operations than local, state and federal governments. One key challenge area is taxation. Tax Authorities face a multitude of IT challenges. Firstly, the data used in tax calculations is increasing in volume and complexity. They must improve service by introducing multi-channel contact centers and self-service capabilities. Security concerns necessitate increasingly sophisticated data protection procedures. And cost constraints are driving Tax Authorities to rely on off-the-shelf software for many of their functional areas. Compounding these issues is the fact that the IT architectures in operation at most revenue and collections agencies are very complex. They typically include multiple, disparate operational and analytical systems across which the sum total of data about individual constituents is fragmented. To make matters more complicated, taxation is not carried out by a single jurisdiction, and often sources of income including employers, investments and other sources of taxable income and deductions must also be tracked and shared among tax authorities. Collectively, these systems are involved in tax assessment and collections, risk analysis, scoring, tracking, auditing and investigation case management. The Problem of Constituent Data Management The infrastructure described above makes it very difficult to create a consolidated representation of a given party. Differing formats and data models mean that a constituent may be represented in one way in one system and in a different way in another. Individual records are frequently inaccurate, incomplete, out of date and/or inconsistent with other records relating to the same constituent. When constituent data must be aggregated and scored, information within each system must be rationalized and normalized so the agency can produce a constituent information file (CIF) that provides a single source of truth about that party. If information about that constituent changes, each system in turn must be updated. There have been many attempts to solve this problem with technology: from consolidating transactional systems to conducting manual systems integration projects and superimposing layers of business intelligence and analytics. All these approaches can be successful in solving a portion of the problem at a specific point in time, but without an enterprise perspective, anything gained is quickly lost again. Oracle Constituent Data Mastering for Tax Authorities: A Single View of the Constituent Oracle has a flexible and long-term solution to the problem of securely integrating and managing constituent data. The Oracle Solution for mastering Constituent Data for Tax Authorities is based on two core product offerings: Oracle Customer Hub and – optionally – Oracle Application Integration Architecture (AIA). Customer Hub is a master data management (MDM) product that centralizes, de-duplicates, and enriches constituent data. It unifies fragmented information without disrupting existing business processes or IT investments. Role based data access and privacy rules guarantee maximum security and privacy. Data is continuously and automatically synchronized with all source systems. With the Oracle Customer Hub managing the master constituent identity, every department can capture transaction activity against the same record, improving reporting accuracy, employee productivity, reliability of constituent analytics, and day-to-day constituent relationships. Oracle Application Integration Architecture provides a collection of core pre-built processes to support out of the box Master Data Governance across Oracle Customer Hub, Siebel CRM, and Oracle E-Business Suite. It also provides a framework to enable MDM integrations with other Oracle and non-Oracle applications. Oracle AIA removes some of the key inhibitors to implementing a service-oriented architecture (SOA) by providing a pre-built SOA-based middleware foundation as well as industry-optimized service oriented applications, all built around a SOA governance model that encourages effective design and reuse. I encourage you to read Oracle Solution for Mastering Constituents Data for Public Sector – Tax Authorities by Roberto Negro. It is an outstanding whitepaper that describes how the Oracle MDM solution allows you to create a unified, reconciled source of high-quality constituent data and gain an accurate single view of each constituent. This foundation enables you to lower the costs associated with data quality and integration and create a tax organization that is efficient, secure and constituent-centric. Also, don’t forget the upcoming webcast on Thursday, February 10th: Deliver Improved Services to Citizens at Lower Cost to your Organization Our Guest Speaker is Ruben Spekle, from Capgemini. He will also provide insight into Public Sector Master Data Management and Case Management implementations including one that was executed for a Dutch Government Agency. If you are interested in how governmental organizations from around the world are using MDM to advance their cause, click here to register for the webcast.

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• Availability Best Practices on Oracle VM Server for SPARC

  - by jsavit

  This is the first of a series of blog posts on configuring Oracle VM Server for SPARC (also called Logical Domains) for availability. This series will show how to how to plan for availability, improve serviceability, avoid single points of failure, and provide resiliency against hardware and software failures. Availability is a broad topic that has filled entire books, so these posts will focus on aspects specifically related to Oracle VM Server for SPARC. The goal is to improve Reliability, Availability and Serviceability (RAS): An article defining RAS can be found here. Oracle VM Server for SPARC Principles for Availability Let's state some guiding principles for availability that apply to Oracle VM Server for SPARC: Avoid Single Points Of Failure (SPOFs). Systems should be configured so a component failure does not result in a loss of application service. The general method to avoid SPOFs is to provide redundancy so service can continue without interruption if a component fails. For a critical application there may be multiple levels of redundancy so multiple failures can be tolerated. Oracle VM Server for SPARC makes it possible to configure systems that avoid SPOFs. Configure for availability at a level of resource and effort consistent with business needs. Effort and resource should be consistent with business requirements. Production has different availability requirements than test/development, so it's worth expending resources to provide higher availability. Even within the category of production there may be different levels of criticality, outage tolerances, recovery and repair time requirements. Keep in mind that a simple design may be more understandable and effective than a complex design that attempts to "do everything". Design for availability at the appropriate tier or level of the platform stack. Availability can be provided in the application, in the database, or in the virtualization, hardware and network layers they depend on - or using a combination of all of them. It may not be necessary to engineer resilient virtualization for stateless web applications applications where availability is provided by a network load balancer, or for enterprise applications like Oracle Real Application Clusters (RAC) and WebLogic that provide their own resiliency. It's (often) the same architecture whether virtual or not: For example, providing resiliency against a lost device path or failing disk media is done for the same reasons and may use the same design whether in a domain or not. It's (often) the same technique whether using domains or not: Many configuration steps are the same. For example, configuring IPMP or creating a redundant ZFS pool is pretty much the same within the guest whether you're in a guest domain or not. There are configuration steps and choices for provisioning the guest with the virtual network and disk devices, which we will discuss. Sometimes it is different using domains: There are new resources to configure. Most notable is the use of alternate service domains, which provides resiliency in case of a domain failure, and also permits improved serviceability via "rolling upgrades". This is an important differentiator between Oracle VM Server for SPARC and traditional virtual machine environments where all virtual I/O is provided by a monolithic infrastructure that itself is a SPOF. Alternate service domains are widely used to provide resiliency in production logical domains environments. Some things are done via logical domains commands, and some are done in the guest: For example, with Oracle VM Server for SPARC we provide multiple network connections to the guest, and then configure network resiliency in the guest via IP Multi Pathing (IPMP) - essentially the same as for non-virtual systems. On the other hand, we configure virtual disk availability in the virtualization layer, and the guest sees an already-resilient disk without being aware of the details. These blogs will discuss configuration details like this. Live migration is not "high availability" in the sense of "continuous availability": If the server is down, then you don't live migrate from it! (A cluster or VM restart elsewhere would be used). However, live migration can be part of the RAS (Reliability, Availability, Serviceability) picture by improving Serviceability - you can move running domains off of a box before planned service or maintenance. The blog Best Practices - Live Migration on Oracle VM Server for SPARC discusses this. Topics Here are some of the topics that will be covered: Network availability using IP Multipathing and aggregates Disk path availability using virtual disks defined with multipath groups ("mpgroup") Disk media resiliency configuring for redundant disks that can tolerate media loss Multiple service domains - this is probably the most significant item and the one most specific to Oracle VM Server for SPARC. It is very widely deployed in production environments as the means to provide network and disk availability, but it can be confusing. Subsequent articles will describe why and how to configure multiple service domains. Note, for the sake of precision: an I/O domain is any domain that has a physical I/O resource (such as a PCIe bus root complex). A service domain is a domain providing virtual device services to other domains; it is almost always an I/O domain too (so it can have something to serve). Resources Here are some important links; we'll be drawing on their content in the next several articles: Oracle VM Server for SPARC Documentation Maximizing Application Reliability and Availability with SPARC T5 Servers whitepaper by Gary Combs Maximizing Application Reliability and Availability with the SPARC M5-32 Server whitepaper by Gary Combs Summary Oracle VM Server for SPARC offers features that can be used to provide highly-available environments. This and the following blog entries will describe how to plan and deploy them.

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• Declarative Architectures in Infrastructure as a Service (IaaS)

  - by BuckWoody

  I deal with computing architectures by first laying out requirements, and then laying in any constraints for it's success. Only then do I bring in computing elements to apply to the system. As an example, a requirement might be "world-side availability" and a constraint might be "with less than 80ms response time and full HA" or something similar. Then I can choose from the best fit of technologies which range from full-up on-premises computing to IaaS, PaaS or SaaS. I also deal in abstraction layers - on-premises systems are fully under your control, in IaaS the hardware is abstracted (but not the OS, scale, runtimes and so on), in PaaS the hardware and the OS is abstracted and you focus on code and data only, and in SaaS everything is abstracted - you merely purchase the function you want (like an e-mail server or some such) and simply use it. When you think about solutions this way, the architecture moves to the primary factor in your decision. It's problem-first architecting, and then laying in whatever technology or vendor best fixes the problem. To that end, most architects design a solution using a graphical tool (I use Visio) and then creating documents that  let the rest of the team (and business) know what is required. It's the template, or recipe, for the solution. This is extremely easy to do for SaaS - you merely point out what the needs are, research the vendor and present the findings (and bill) to the business. IT might not even be involved there. In PaaS it's not much more complicated - you use the same Application Lifecycle Management and design tools you always have for code, such as Visual Studio or some other process and toolset, and you can "stamp out" the application in multiple locations, update it and so on. IaaS is another story. Here you have multiple machines, operating systems, patches, virus scanning, run-times, scale-patterns and tools and much more that you have to deal with, since essentially it's just an in-house system being hosted by someone else. You can certainly automate builds of servers - we do this as technical professionals every day. From Windows to Linux, it's simple enough to create a "build script" that makes a system just like the one we made yesterday. What is more problematic is being able to tie those systems together in a coherent way (as a solution) and then stamp that out repeatedly, especially when you might want to deploy that solution on-premises, or in one cloud vendor or another. Lately I've been working with a company called RightScale that does exactly this. I'll point you to their site for more info, but the general idea is that you document out your intent for a set of servers, and it will deploy them to on-premises clouds, Windows Azure, and other cloud providers all from the same script. In other words, it doesn't contain the images or anything like that - it contains the scripts to build them on-premises or on a cloud vendor like Microsoft. Using a tool like this, you combine the steps of designing a system (all the way down to passwords and accounts if you wish) and then the document drives the distribution and implementation of that intent. As time goes on and more and more companies implement solutions on various providers (perhaps for HA and DR) then this becomes a compelling investigation. The RightScale information is here, if you want to investigate it further. Yes, there are other methods I've found, but most are tied to a single kind of cloud, and I'm not into vendor lock-in. Poppa Bear Level - Hands-on EvaluateRightScale at no cost.  Just bring your Windows Azurecredentials and follow the these tutorials: Sign Up for Windows Azure Add     Windows Azure to a RightScale Account Windows Azure Virtual Machines     3-tier Deployment Momma Bear Level - Just the Right level... ;0)  WindowsAzure Evaluation Guide - if you are new toWindows Azure Virtual Machines and new to RightScale, we recommend that youread the entire evaluation guide to gain a more complete understanding of theWindows Azure + RightScale solution.    WindowsAzure Support Page @ support.rightscale.com - FAQ's, tutorials,etc. for  Windows Azure Virtual Machines (Work in Progress) Baby Bear Level - Marketing WindowsAzure Page @ www.rightscale.com - find overview informationincluding solution briefs and presentation & demonstration videos   Scale     and Automate Applications on Windows Azure  Solution Brief     - how RightScale makes Windows Azure Virtual Machine even better SQL     Server on Windows Azure  Solution Brief   -       Run Highly Available SQL Server on Windows Azure Virtual Machines

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• Infiniband: a highperformance network fabric - Part I

  - by Karoly Vegh

  Introduction:At the OpenWorld this year I managed to chat with interesting people again - one of them answering Infiniband deepdive questions with ease by coffee turned out to be one of Oracle's IB engineers, Ted Kim, who actually actively participates in the Infiniband Trade Association and integrates Oracle solutions with this highspeed network. This is why I love attending OOW. He granted me an hour of his time to talk about IB. This post is mostly based on that tech interview.Start of the actual post: Traditionally datatransfer between servers and storage elements happens in networks with up to 10 gigabit/seconds or in SANs with up to 8 gbps fiberchannel connections. Happens. Well, data rather trickles through.But nowadays data amounts grow well over the TeraByte order of magnitude, and multisocket/multicore/multithread Servers hunger data that these transfer technologies just can't deliver fast enough, causing all CPUs of this world do one thing at the same speed - waiting for data. And once again, I/O is the bottleneck in computing. FC and Ethernet can't keep up. We have half-TB SSDs, dozens of TB RAM to store data to be modified in, but can't transfer it. Can't backup fast enough, can't replicate fast enough, can't synchronize fast enough, can't load fast enough. The bad news is, everyone is used to this, like back in the '80s everyone was used to start compile jobs and go for a coffee. Or on vacation. The good news is, there's an alternative. Not so-called "bleeding-edge" 8gbps, but (as of now) 56. Not layers of overhead, but low latency. And it is available now. It has been for a while, actually. Welcome to the world of Infiniband. Short history:Infiniband was born as a result of joint efforts of HPAQ, IBM, Intel, Sun and Microsoft. They planned to implement a next-generation I/O fabric, in the 90s. In the 2000s Infiniband (from now on: IB) was quite popular in the high-performance computing field, powering most of the top500 supercomputers. Then in the middle of the decade, Oracle realized its potential and used it as an interconnect backbone for the first Database Machine, the first Exadata. Since then, IB has been booming, Oracle utilizes and supports it in a large set of its HW products, it is the backbone of the famous Engineered Systems: Exadata, SPARC SuperCluster, Exalogic, OVCA and even the new DB backup/recovery box. You can also use it to make servers talk highspeed IP to eachother, or to a ZFS Storage Appliance. Following Oracle's lead, even IBM has jumped the wagon, and leverages IB in its PureFlex systems, their first InfiniBand Machines.IB Structural Overview: If you want to use IB in your servers, the first thing you will need is PCI cards, in IB terms Host Channel Adapters, or HCAs. Just like NICs for Ethernet, or HBAs for FC. In these you plug an IB cable, going to an IB switch providing connection to other IB HCAs. Of course you're going to need drivers for those in your OS. Yes, these are long-available for Solaris and Linux. Now, what protocols can you talk over IB? There's a range of choices. See, IB isn't accepting package loss like Ethernet does, and hence doesn't need to rely on TCP/IP as a workaround for resends. That is, you still can run IP over IB (IPoIB), and that is used in various cases for control functionality, but the datatransfer can run over more efficient protocols - like native IB. About PCI connectivity: IB cards, as you see are fast. They bring low latency, which is just as important as their bandwidth. Current IB cards run at 56 gbit/s. That is slightly more than double of the capacity of a PCI Gen2 slot (of ~25 gbit/s). And IB cards are equipped usually with two ports - that is, altogether you'd need 112 gbit/s PCI slots, to be able to utilize FDR IB cards in an active-active fashion. PCI Gen3 slots provide you with around ~50gbps. This is why the most IB cards are configured in an active-standby way if both ports are used. Once again the PCI slot is the bottleneck. Anyway, the new Oracle servers are equipped with Gen3 PCI slots, an the new IB HCAs support those too. Oracle utilizes the QDR HCAs, running at 40gbp/s brutto, which translates to a 32gbp/s net traffic due to the 10:8 signal-to-data information ratio. Consolidation techniques: Technology never stops to evolve. Mellanox is working on the 100 gbps (EDR) version already, which will be optical, since signal technology doesn't allow EDR to be copper. Also, I hear you say "100gbps? I will never use/need that much". Are you sure? Have you considered consolidation scenarios, where (for example with Oracle Virtual Network) you could consolidate your platform to a high densitiy virtualized solution providing many virtual 10gbps interfaces through that 100gbps? Technology never stops to evolve. I still remember when a 10mbps network was impressively fast. Back in those days, 16MB of RAM was a lot. Now we usually run servers with around 100.000 times more RAM. If network infrastrucure speends could grow as fast as main memory capacities, we'd have a different landscape now :) You can utilize SRIOV as well for consolidation. That is, if you run LDoms (aka Oracle VM Server for SPARC) you do not have to add physical IB cards to all your guest LDoms, and you do not need to run VIO devices through the hypervisor either (avoiding overhead). You can enable SRIOV on those IB cards, which practically virtualizes the PCI bus, and you can dedicate Physical- and Virtual Functions of the virtualized HCAs as native, physical HW devices to your guests. See Raghuram's excellent post explaining SRIOV. SRIOV for IB is supported since LDoms 3.1.  This post is getting lengthier, so I will rename it to Part I, and continue it in a second post. 

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• Private Cloud: Putting some method behind the madness

  - by Sudip Datta

  Finally, I decided to join the blogging community. And what could be a better time to start than the week after OpenWorld 2012. 50K+ attendees, demonstrations, speaker sessions and a whole lot of buzz on Oracle Cloud..It was raining clouds in this year's Openworld. I am not here to write about Oracle's cloud strategy in general, but on Enterprise Manager's cloud management capabilities. This year's Openworld was the first after we announced the 12c Cloud Control and we were happy to share the stage with quite a few early adopters. Stay tuned for videos from our customers and partners, I will post them as they get published. I met a number of platform administrators in Oracle-DBAs, Middleware Admins, SOA Admins...The cloud has affected them all, at least to the point where it beckoned more than just curiosity..Most IT infrastructure are already heavily virtualized (on VMWare and on others including Oracle VM), and some would claim they are already on “cloud” (at least their Sysadmins told them so). But none of them were confident of the benefits because their pain points continued to grow.. Isn't cloud supposed to ease those? Instead, they were chasing hundreds of databases running on hundreds of VMs, often with as much certainty propounded by Heisenberg. What happened to the age-old IT discipline around administration, compliance, configuration management? VMs are great for what they are. I personally think they have opened the doors to new approaches in which an application stack gets provisioned and updated. In fact, Enterprise Manager 12c is possibly the only tool out there that can provision full-fledged application as VM Assemblies. In this year's Openworld, customers talked on how they provisioned RAC and Siebel assemblies, which as the techies out there know, are not trivial (hearing provisioning time for Siebel down from weeks to hours was gratifying indeed). However, I do have an issue with a "one-size fits all" approach to cloud. In a week's span, I met several personas: Project owners requiring an EC2 like VM instance for their projects Admins needing the same for Sparc-Solaris. DBAs requiring dedicated databases for new projects APEX Developers needing just a ready-to-consume schema as a service Java Developers looking for a runtime platform QA engineers needing a fast clone of their production environment If you drill down further, you will end up peeling more layers of the details. For example, the requirements for Load testing and Functional testing are very different. For Load testing the test environment should ideally be the same as the production. You shouldn't run production on Exadata and load test on a VM; they will just not be good representations of one another. For Functional testing it does not possibly matter. DBAs seem to be at the worst affected of the lot. It seems they have been asked to choose between agile provisioning and  faster runtime performance. And in some cases, it is really a Hobson's choice, because their infrastructure provider made no distinction between the OLTP application and the Virtual desktop! Sad indeed. When one looks at the portfolio of services that we already offer (vanilla IaaS, VM Assembly based PaaS, DBaaS) or have announced (Java PaaS, Instant Cloning, Schema-aaS), one can possibly think that we are trying to be the "renaissance man" ! Well I would have possibly digested that had it not been for the various personas that I described above. Getting the use cases right is very important for an application such as cloud management. We iterate and iterate over these over and over again and re-validate them in CABs (Customer Advisory Boards). We consider over the major aspects of tenancy: service placement, resource isolation (can a tenant execute an expensive SQL and run away with all the resources), quota and security. We, in Engineering, keep reminding ourselves that we are dealing with enterprise clouds. We owe it to our customer base ! In the coming posts, I will drill down more into each of the services. In the meanwhile, here are some collateral and  demos for starters with EM 12c. http://www.oracle.com/technetwork/oem/cloud-mgmt/index.html Sudip Datta The views expressed here are my own and do not necessarily reflect the views of Oracle. Stay Connected: Twitter | Facebook | YouTube | Linkedin | Newsletter --

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