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• Dell Continues to Rise

  Server Snapshot: Dell has pushed Sun out of the No. 3 server spot. Given the OEM's new array of products, will it be long before Dell's ascendancy places it at IBM's and HP's backs?

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• Dell Continues to Rise

  Server Snapshot: Dell has pushed Sun out of the No. 3 server spot. Given the OEM's new array of products, will it be long before Dell's ascendancy places it at IBM's and HP's backs?

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• Fluid VS Responsive Website Development Questions

  - by Aditya P

  As I understand these form the basis for targeting a wide array of devices based on the browser size, given it would be a time consuming to generate different layouts targeting different/specific devices and their resolutions. Questions: Firstly right to the jargon, is there any actual difference between the two or do they mean the same? Is it safe to classify the current development mainly a html5/css3 based one? What popular frameworks are available to easily implement this? What testing methods used in this regard? What are the most common compatibility issues in terms of different browser types? I understand there are methods like this http://css-tricks.com/resolution-specific-stylesheets/ which does this come under?. Are there any external browser detection methods besides the API calls specific to the browser that are employed in this regard? Points of interest [Prior Research before asking these questions] Why shouldn't "responsive" web design be a consideration? Responsive Web Design Tips, Best Practices and Dynamic Image Scaling Techniques A recent list of tutorials 30 Responsive Web Design and Development Tutorials by Eric Shafer on May 14, 2012 Update Ive been reading that the basic point of designing content for different layouts to facilitate a responsive web design is to present the most relevant information. now obviously between the smallest screen width and the highest we are missing out on design elements. I gather from here http://flashsolver.com/2012/03/24/5-top-commercial-responsive-web-designs/ The top of the line design layouts (widths) are desktop layout (980px) tablet layout (768px) smartphone layout – landscape (480px) smartphone layout – portrait (320px) Also we have a popular responsive website testing site http://resizemybrowser.com/ which lists different screen resolutions. I've also come across this while trying to find out the optimal highest layout size to account for http://stackoverflow.com/questions/10538599/default-web-page-width-1024px-or-980px which brings to light seemingly that 1366x768 is a popular web resolution. Is it safe to assume that just accounting for proper scaling from width 980px onwards to the maximum size would be sufficient to accommodate this? given we aren't presenting any new information for the new size. Does it make sense to have additional information ( which conflicts with purpose of responsive web design) to utilize the top size and beyond?

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• Is it possible to billboard a sprite using a transformation matrix?

  - by Ross

  None of the current topics on billboarding seemed to answer this question. But, given a sprite (or quad) that has it's own 4x4 transformation matrix a camera with a view matrix (a standard 4x4 transformation matrix) is it possible to compute a 4x4 transformation matrix such that when the quad's matrix is multiplied with this matrix it has an orientation of looking at the camera? Thank you in advance.

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• Are there any books that teach techniques for effective pair programming?

  - by Paul D. Waite

  I’ve just read the pair programming chapter of ‘Making Software’ by Andy Oram, and I’d like to try it when I next get an opportunity. The chapter mentions that in one of the studies, the subjects were initially given instruction on effective pair programming. Are there any books (or chapters of books) that I could read to get a good grounding in how to do pair programming effectively, so that I’m more prepared?

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• Thread placement policies on NUMA systems - update

  - by Dave

  In a prior blog entry I noted that Solaris used a "maximum dispersal" placement policy to assign nascent threads to their initial processors. The general idea is that threads should be placed as far away from each other as possible in the resource topology in order to reduce resource contention between concurrently running threads. This policy assumes that resource contention -- pipelines, memory channel contention, destructive interference in the shared caches, etc -- will likely outweigh (a) any potential communication benefits we might achieve by packing our threads more densely onto a subset of the NUMA nodes, and (b) benefits of NUMA affinity between memory allocated by one thread and accessed by other threads. We want our threads spread widely over the system and not packed together. Conceptually, when placing a new thread, the kernel picks the least loaded node NUMA node (the node with lowest aggregate load average), and then the least loaded core on that node, etc. Furthermore, the kernel places threads onto resources -- sockets, cores, pipelines, etc -- without regard to the thread's process membership. That is, initial placement is process-agnostic. Keep reading, though. This description is incorrect. On Solaris 10 on a SPARC T5440 with 4 x T2+ NUMA nodes, if the system is otherwise unloaded and we launch a process that creates 20 compute-bound concurrent threads, then typically we'll see a perfect balance with 5 threads on each node. We see similar behavior on an 8-node x86 x4800 system, where each node has 8 cores and each core is 2-way hyperthreaded. So far so good; this behavior seems in agreement with the policy I described in the 1st paragraph. I recently tried the same experiment on a 4-node T4-4 running Solaris 11. Both the T5440 and T4-4 are 4-node systems that expose 256 logical thread contexts. To my surprise, all 20 threads were placed onto just one NUMA node while the other 3 nodes remained completely idle. I checked the usual suspects such as processor sets inadvertently left around by colleagues, processors left offline, and power management policies, but the system was configured normally. I then launched multiple concurrent instances of the process, and, interestingly, all the threads from the 1st process landed on one node, all the threads from the 2nd process landed on another node, and so on. This happened even if I interleaved thread creating between the processes, so I was relatively sure the effect didn't related to thread creation time, but rather that placement was a function of process membership. I this point I consulted the Solaris sources and talked with folks in the Solaris group. The new Solaris 11 behavior is intentional. The kernel is no longer using a simple maximum dispersal policy, and thread placement is process membership-aware. Now, even if other nodes are completely unloaded, the kernel will still try to pack new threads onto the home lgroup (socket) of the primordial thread until the load average of that node reaches 50%, after which it will pick the next least loaded node as the process's new favorite node for placement. On the T4-4 we have 64 logical thread contexts (strands) per socket (lgroup), so if we launch 48 concurrent threads we will find 32 placed on one node and 16 on some other node. If we launch 64 threads we'll find 32 and 32. That means we can end up with our threads clustered on a small subset of the nodes in a way that's quite different that what we've seen on Solaris 10. So we have a policy that allows process-aware packing but reverts to spreading threads onto other nodes if a node becomes too saturated. It turns out this policy was enabled in Solaris 10, but certain bugs suppressed the mixed packing/spreading behavior. There are configuration variables in /etc/system that allow us to dial the affinity between nascent threads and their primordial thread up and down: see lgrp_expand_proc_thresh, specifically. In the OpenSolaris source code the key routine is mpo_update_tunables(). This method reads the /etc/system variables and sets up some global variables that will subsequently be used by the dispatcher, which calls lgrp_choose() in lgrp.c to place nascent threads. Lgrp_expand_proc_thresh controls how loaded an lgroup must be before we'll consider homing a process's threads to another lgroup. Tune this value lower to have it spread your process's threads out more. To recap, the 'new' policy is as follows. Threads from the same process are packed onto a subset of the strands of a socket (50% for T-series). Once that socket reaches the 50% threshold the kernel then picks another preferred socket for that process. Threads from unrelated processes are spread across sockets. More precisely, different processes may have different preferred sockets (lgroups). Beware that I've simplified and elided details for the purposes of explication. The truth is in the code. Remarks: It's worth noting that initial thread placement is just that. If there's a gross imbalance between the load on different nodes then the kernel will migrate threads to achieve a better and more even distribution over the set of available nodes. Once a thread runs and gains some affinity for a node, however, it becomes "stickier" under the assumption that the thread has residual cache residency on that node, and that memory allocated by that thread resides on that node given the default "first-touch" page-level NUMA allocation policy. Exactly how the various policies interact and which have precedence under what circumstances could the topic of a future blog entry. The scheduler is work-conserving. The x4800 mentioned above is an interesting system. Each of the 8 sockets houses an Intel 7500-series processor. Each processor has 3 coherent QPI links and the system is arranged as a glueless 8-socket twisted ladder "mobius" topology. Nodes are either 1 or 2 hops distant over the QPI links. As an aside the mapping of logical CPUIDs to physical resources is rather interesting on Solaris/x4800. On SPARC/Solaris the CPUID layout is strictly geographic, with the highest order bits identifying the socket, the next lower bits identifying the core within that socket, following by the pipeline (if present) and finally the logical thread context ("strand") on the core. But on Solaris on the x4800 the CPUID layout is as follows. [6:6] identifies the hyperthread on a core; bits [5:3] identify the socket, or package in Intel terminology; bits [2:0] identify the core within a socket. Such low-level details should be of interest only if you're binding threads -- a bad idea, the kernel typically handles placement best -- or if you're writing NUMA-aware code that's aware of the ambient placement and makes decisions accordingly. Solaris introduced the so-called critical-threads mechanism, which is expressed by putting a thread into the FX scheduling class at priority 60. The critical-threads mechanism applies to placement on cores, not on sockets, however. That is, it's an intra-socket policy, not an inter-socket policy. Solaris 11 introduces the Power Aware Dispatcher (PAD) which packs threads instead of spreading them out in an attempt to be able to keep sockets or cores at lower power levels. Maximum dispersal may be good for performance but is anathema to power management. PAD is off by default, but power management polices constitute yet another confounding factor with respect to scheduling and dispatching. If your threads communicate heavily -- one thread reads cache lines last written by some other thread -- then the new dense packing policy may improve performance by reducing traffic on the coherent interconnect. On the other hand if your threads in your process communicate rarely, then it's possible the new packing policy might result on contention on shared computing resources. Unfortunately there's no simple litmus test that says whether packing or spreading is optimal in a given situation. The answer varies by system load, application, number of threads, and platform hardware characteristics. Currently we don't have the necessary tools and sensoria to decide at runtime, so we're reduced to an empirical approach where we run trials and try to decide on a placement policy. The situation is quite frustrating. Relatedly, it's often hard to determine just the right level of concurrency to optimize throughput. (Understanding constructive vs destructive interference in the shared caches would be a good start. We could augment the lines with a small tag field indicating which strand last installed or accessed a line. Given that, we could augment the CPU with performance counters for misses where a thread evicts a line it installed vs misses where a thread displaces a line installed by some other thread.)

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• SQL Server Impersonation

  SQL Server impersonation, or context switching, is a means to allow the executing user to assume the permissions of a given user or login until the context is set back, set to yet another user, or the session is ended. Deanna Dicken shows you two mechanisms for accomplishing this task and walks through some examples.

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• Fastest Functional Language

  - by Farouk

  I've recently been delving into functional programming especially Haskell and F#, the prior more so. After some googling around I could not find a benchmark comparison of the more prominent functional languages (Scala,F# etc). I know it's not necessarily fair to some of the languages (Scala comes to mind) given that they are hybrids, but I just wanna know which outperforms which on what operations and overall.

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• Bit-Twiddling in SQL

  - by Mike C

  Someone posted a question to the SQL Server forum the other day asking how to count runs of zero bits in an integer using SQL. Basically the poster wanted to know how to efficiently determine the longest contiguous string of zero-bits (known as a run of bits) in any given 32-bit integer. Here are a couple of examples to demonstrate the idea: Decimal = Binary = Zero Run 999,999,999 decimal = 00 111011 1 00 11010 11 00 1 00 1 11111111 binary = 2 contiguous zero bits 666,666,666 decimal = 00100111 10111100...(read more)

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• Is eval the defmacro of javascript?

  - by Florian Margaine

  In Common Lisp, defmacro basically allows us to build our own DSL. I read this page today and it explains something cleverly done: But I wasn't about to write out all these boring predicates myself, so I defined a function that, given a list of words, builds up the text for such a predicate automatically, and then evals it to produce a function. Which just looks like defmacro to me. Is eval the defmacro of javascript? Could it be used as such?

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• How to Create Progress Bars in Excel With Conditional Formatting

  - by Erez Zukerman

  Progress bars are pretty much ubiquitous these days; we’ve even seen them on some water coolers. A progress bar provides instant feedback on a given process, so why not bring some of that graphical pizzazz into your spreadsheet, using Excel’s Conditional Formatting feature?HTG Explains: What Are Character Encodings and How Do They Differ?How To Make Disposable Sleeves for Your In-Ear MonitorsMacs Don’t Make You Creative! So Why Do Artists Really Love Apple?

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• Automated build platform for .NET portfolio - best choice?

  - by jkohlhepp

  I am involved with maintaining a fairly large portfolio of .NET applications. Also in the portfolio are legacy applications built on top of other platforms - native C++, ECLIPS Forms, etc. I have a complex build framework on top of NAnt right now that manages the builds for all of these applications. The build framework uses NAnt to do a number of different things: Pull code out of Subversion, as well as create tags in Subversion Build the code, using MSBuild for .NET or other compilers for other platforms Peek inside AssemblyInfo files to increment version numbers Do deletes of certain files that shouldn't be included in builds / releases Releases code to deployment folders Zips code up for backup purposes Deploy Windows services; start and stop them Etc. Most of those things can be done with just NAnt by itself, but we did build a couple of extension tasks for NAnt to do some things that were specific to our environment. Also, most of those processes above are genericized and reused across a lot of our different application build scripts, so that we don't repeat logic. So it is not simple NAnt code, and not simple build scripts. There are dozens of NAnt files that come together to execute a build. Lately I've been dissatisfied with NAnt for a couple reasons: (1) it's syntax is just awful - programming languages on top of XML are really horrific to maintain, (2) the project seems to have died on the vine; there haven't been a ton of updates lately and it seems like no one is really at the helm. Trying to get it working with .NET 4 has cause some pain points due to this lack of activity. So, with all of that background out of the way, here's my question. Given some of the things that I want to accomplish based on that list above, and given that I am primarily in a .NET shop, but I also need to build non-.NET projects, is there an alternative to NAnt that I should consider switching to? Things on my radar include Powershell (with or without psake), MSBuild by itself, and rake. These all have pros and cons. For example, is MSBuild powerful enough? I remember using it years ago and it didn't seem to have as much power as NAnt. Do I really want to have my team learn Ruby just to do builds using rake? Is psake really mature enough of a project to pin my portfolio to? Is Powershell "too close to the metal" and I'll end up having to write my own build library akin to psake to use it on its own? Are there other tools that I should consider? If you were involved with maintaining a .NET portfolio of significant complexity, what build tool would you be looking at? What does your team currently use?

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• Few Steps For Making Your Website SEO Friendly

  Currently going by the dynamics of the internet every web designer of class is expected to be acquainted with or have a basic working knowledge of search engine optimization tools. Web promotion as an optimization tool for enhancing increased traffic to a given site is one skill web designers just like online marketers require in their respective fields to conquer the market.

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• Webmasters Out of Control

  I've written about this topic before and it is one of my pet hates, small business owners who pay webmasters to build web sites for them and then are never given access to the files or the "engine room" of the site to be able to make on page SEO changes and more importantly get the site better rankings on search engines such as Google. SEO is not set and forget, because you need to constantly make changes and massage pages on your site.

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• Where and how to reference composite MVP components?

  - by Lea Hayes

  I am learning about the MVP (Model-View-Presenter) Passive View flavour of MVC. I intend to expose events from view interfaces rather than using the observer pattern to remove explicit coupling with presenter. Context: Windows Forms / Client-Side JavaScript. I am led to believe that the MVP (or indeed MVC in general) pattern can be applied at various levels of a user interface ranging from the main "Window" to an embedded "Text Field". For instance, the model to the text field is probably just a string whereas the model to the "Window" contains application specific view state (like a persons name which resides within the contained text field). Given a more complex scenario: Documentation viewer which contains: TOC navigation pane Document view Search pane Since each of these 4 user interface items are complex and can be reused elsewhere it makes sense to design these using MVP. Given that each of these user interface items comprises of 3 components; which component should be nested? where? who instantiates them? Idea #1 - Embed View inside View from Parent View public class DocumentationViewer : Form, IDocumentationViewerView { public DocumentationViewer() { ... // Unclear as to how model and presenter are injected... TocPane = new TocPaneView(); } protected ITocPaneView TocPane { get; private set; } } Idea #2 - Embed Presenter inside View from Parent View public class DocumentationViewer : Form, IDocumentationViewerView { public DocumentationViewer() { ... // This doesn't seem like view logic... var tocPaneModel = new TocPaneModel(); var tocPaneView = new TocPaneView(); TocPane = new TocPanePresenter(tocPaneModel, tocPaneView); } protected TocPanePresenter TocPane { get; private set; } } Idea #3 - Embed View inside View from Parent Presenter public class DocumentationViewer : Form, IDocumentationViewerView { ... // Part of IDocumentationViewerView: public ITocPaneView TocPane { get; set; } } public class DocumentationViewerPresenter { public DocumentationViewerPresenter(DocumentationViewerModel model, IDocumentationViewerView view) { ... var tocPaneView = new TocPaneView(); var tocPaneModel = new TocPaneModel(model.Toc); var tocPanePresenter = new TocPanePresenter(tocPaneModel, tocPaneView); view.TocPane = tocPaneView; } } Some better idea...

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• A Perspective on Database Performance Tuning

  Fundamentally, database performance tuning is done for two basic reasons, to reduce response time and to reduce resource usage, both of which can apply for any given situation. Julian Stuhler looks at database performance tuning, and why it remains one of the most important topics for any DBA, developer or systems administrator.

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• Space partitioning when everything is moving

  - by Roy T.

  Background Together with a friend I'm working on a 2D game that is set in space. To make it as immersive and interactive as possible we want there to be thousands of objects freely floating around, some clustered together, others adrift in empty space. Challenge To unburden the rendering and physics engine we need to implement some sort of spatial partitioning. There are two challenges we have to overcome. The first challenge is that everything is moving so reconstructing/updating the data structure has to be extremely cheap since it will have to be done every frame. The second challenge is the distribution of objects, as said before there might be clusters of objects together and vast bits of empty space and to make it even worse there is no boundary to space. Existing technologies I've looked at existing techniques like BSP-Trees, QuadTrees, kd-Trees and even R-Trees but as far as I can tell these data structures aren't a perfect fit since updating a lot of objects that have moved to other cells is relatively expensive. What I've tried I made the decision that I need a data structure that is more geared toward rapid insertion/update than on giving back the least amount of possible hits given a query. For that purpose I made the cells implicit so each object, given it's position, can calculate in which cell(s) it should be. Then I use a HashMap that maps cell-coordinates to an ArrayList (the contents of the cell). This works fairly well since there is no memory lost on 'empty' cells and its easy to calculate which cells to inspect. However creating all those ArrayLists (worst case N) is expensive and so is growing the HashMap a lot of times (although that is slightly mitigated by giving it a large initial capacity). Problem OK so this works but still isn't very fast. Now I can try to micro-optimize the JAVA code. However I'm not expecting too much of that since the profiler tells me that most time is spent in creating all those objects that I use to store the cells. I'm hoping that there are some other tricks/algorithms out there that make this a lot faster so here is what my ideal data structure looks like: The number one priority is fast updating/reconstructing of the entire data structure Its less important to finely divide the objects into equally sized bins, we can draw a few extra objects and do a few extra collision checks if that means that updating is a little bit faster Memory is not really important (PC game)

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• New DMF for SQL Server 2008 sys.dm_fts_parser to parse a string

  Many times we want to split a string into an array and get a list of each word separately. The sys.dm_fts_parser function will help us in these cases. More over, this function will also differentiate the noise words and exact match words. The sys.dm_fts_parser can be also very powerful for debugging purposes. It can help you check how the word breaker and stemmer works for a given input for Full Text Search.

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• Spring 3 learning curve

  - by Lucian Enache

  I'm coming from a Struts background and I was considering learning the Spring framework. How long would it usually take to get familiarity with Spring Core and Spring MVC modules, keeping in mind that I come from a Struts 1 background ? Beside those two modules are there any other modules that I should focus on ? I know that the time is relative given that everyone has a different learning curve.

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• Cost Comparison Hard Disk Drive to Solid State Drive on Price per Gigabyte - dispelling a myth!

  - by tonyrogerson

  It is often said that Hard Disk Drive storage is significantly cheaper per GiByte than Solid State Devices – this is wholly inaccurate within the database space. People need to look at the cost of the complete solution and not just a single component part in isolation to what is really required to meet the business requirement. Buying a single Hitachi Ultrastar 600GB 3.5” SAS 15Krpm hard disk drive will cost approximately £239.60 (http://scan.co.uk, 22nd March 2012) compared to an OCZ 600GB Z-Drive R4 CM84 PCIe costing £2,316.54 (http://scan.co.uk, 22nd March 2012); I’ve not included FusionIO ioDrive because there is no public pricing available for it – something I never understand and personally when companies do this I immediately think what are they hiding, luckily in FusionIO’s case the product is proven though is expensive compared to OCZ enterprise offerings. On the face of it the single 15Krpm hard disk has a price per GB of £0.39, the SSD £3.86; this is what you will see in the press and this is what sales people will use in comparing the two technologies – do not be fooled by this bullshit people! What is the requirement? The requirement is the database will have a static size of 400GB kept static through archiving so growth and trim will balance the database size, the client requires resilience, there will be several hundred call centre staff querying the database where queries will read a small amount of data but there will be no hot spot in the data so the randomness will come across the entire 400GB of the database, estimates predict that the IOps required will be approximately 4,000IOps at peak times, because it’s a call centre system the IO latency is important and must remain below 5ms per IO. The balance between read and write is 70% read, 30% write. The requirement is now defined and we have three of the most important pieces of the puzzle – space required, estimated IOps and maximum latency per IO. Something to consider with regard SQL Server; write activity requires synchronous IO to the storage media specifically the transaction log; that means the write thread will wait until the IO is completed and hardened off until the thread can continue execution, the requirement has stated that 30% of the system activity will be write so we can expect a high amount of synchronous activity. The hardware solution needs to be defined; two possible solutions: hard disk or solid state based; the real question now is how many hard disks are required to achieve the IO throughput, the latency and resilience, ditto for the solid state. Hard Drive solution On a test on an HP DL380, P410i controller using IOMeter against a single 15Krpm 146GB SAS drive, the throughput given on a transfer size of 8KiB against a 40GiB file on a freshly formatted disk where the partition is the only partition on the disk thus the 40GiB file is on the outer edge of the drive so more sectors can be read before head movement is required: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 3,733 IOps at an average latency of 34.06ms (34 MiB/s). The same test was done on the same disk but the test file was 130GiB: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 528 IOps at an average latency of 217.49ms (4 MiB/s). From the result it is clear random performance gets worse as the disk fills up – I’m currently writing an article on short stroking which will cover this in detail. Given the work load is random in nature looking at the random performance of the single drive when only 40 GiB of the 146 GB is used gives near the IOps required but the latency is way out. Luckily I have tested 6 x 15Krpm 146GB SAS 15Krpm drives in a RAID 0 using the same test methodology, for the same test above on a 130 GiB for each drive added the performance boost is near linear, for each drive added throughput goes up by 5 MiB/sec, IOps by 700 IOps and latency reducing nearly 50% per drive added (172 ms, 94 ms, 65 ms, 47 ms, 37 ms, 30 ms). This is because the same 130GiB is spread out more as you add drives 130 / 1, 130 / 2, 130 / 3 etc. so implicit short stroking is occurring because there is less file on each drive so less head movement required. The best latency is still 30 ms but we have the IOps required now, but that’s on a 130GiB file and not the 400GiB we need. Some reality check here: a) the drive randomness is more likely to be 50/50 and not a full 100% but the above has highlighted the effect randomness has on the drive and the more a drive fills with data the worse the effect. For argument sake let us assume that for the given workload we need 8 disks to do the job, for resilience reasons we will need 16 because we need to RAID 1+0 them in order to get the throughput and the resilience, RAID 5 would degrade performance. Cost for hard drives: 16 x £239.60 = £3,833.60 For the hard drives we will need disk controllers and a separate external disk array because the likelihood is that the server itself won’t take the drives, a quick spec off DELL for a PowerVault MD1220 which gives the dual pathing with 16 disks 146GB 15Krpm 2.5” disks is priced at £7,438.00, note its probably more once we had two controller cards to sit in the server in, racking etc. Minimum cost taking the DELL quote as an example is therefore: {Cost of Hardware} / {Storage Required} £7,438.60 / 400 = £18.595 per GB £18.59 per GiB is a far cry from the £0.39 we had been told by the salesman and the myth. Yes, the storage array is composed of 16 x 146 disks in RAID 10 (therefore 8 usable) giving an effective usable storage availability of 1168GB but the actual storage requirement is only 400 and the extra disks have had to be purchased to get the  IOps up. Solid State Drive solution A single card significantly exceeds the IOps and latency required, for resilience two will be required. ( £2,316.54 * 2 ) / 400 = £11.58 per GB With the SSD solution only two PCIe sockets are required, no external disk units, no additional controllers, no redundant controllers etc. Conclusion I hope by showing you an example that the myth that hard disk drives are cheaper per GiB than Solid State has now been dispelled - £11.58 per GB for SSD compared to £18.59 for Hard Disk. I’ve not even touched on the running costs, compare the costs of running 18 hard disks, that’s a lot of heat and power compared to two PCIe cards!Just a quick note: I've left a fair amount of information out due to this being a blog! If in doubt, email me :)I'll also deal with the myth that SSD's wear out at a later date as well - that's just way over done still, yes, 5 years ago, but now - no.

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• Design for complex ATG applications

  - by Glen Borkowski

  Overview Needless to say, some ATG applications are more complex than others.  Some ATG applications support a single site, single language, single catalog, single currency, have a single development staff, single business team, and a relatively simple business model.  The real complex applications have to support multiple sites, multiple languages, multiple catalogs, multiple currencies, a couple different development teams, multiple business teams, and a highly complex business model (and processes to go along with it).  While it's still important to implement a proper design for simple applications, it's absolutely critical to do this for the complex applications.  Why?  It's all about time and money.  If you are unable to manage your complex applications in an efficient manner, the cost of managing it will increase dramatically as will the time to get things done (time to market).  On the positive side, your competition is most likely in the same situation, so you just need to be more efficient than they are. This article is intended to discuss a number of key areas to think about when designing complex applications on ATG.  Some of this can get fairly technical, so it may help to get some background first.  You can get enough of the required background information from this post.  After reading that, come back here and follow along. Application Design Of all the various types of ATG applications out there, the most complex tend to be the ones in the telecommunications industry - especially the ones which operate in multiple countries.  To get started, let's assume that we are talking about an application like that.  One that has these properties: Operates in multiple countries - must support multiple sites, catalogs, languages, and currencies The organization is fairly loosely-coupled - single brand, but different businesses across different countries There is some common functionality across all sites in all countries There is some common functionality across different sites within the same country Sites within a single country may have some unique functionality - relative to other sites in the same country Complex product catalog (mostly in terms of bundles, eligibility, and compatibility) At this point, I'll assume you have read through the required reading and have a decent understanding of how ATG modules work... Code / configuration - assemble into modules When it comes to defining your modules for a complex application, there are a number of goals: Divide functionality between the modules in a way that maps to your business Group common functionality 'further down in the stack of modules' Provide a good balance between shared resources and autonomy for countries / sites Now I'll describe a high level approach to how you could accomplish those goals...  Let's start from the bottom and work our way up.  At the very bottom, you have the modules that ship with ATG - the 'out of the box' stuff.  You want to make sure that you are leveraging all the modules that make sense in order to get the most value from ATG as possible - and less stuff you'll have to write yourself.  On top of the ATG modules, you should create what we'll refer to as the Corporate Foundation Module described as follows: Sits directly on top of ATG modules Used by all applications across all countries and sites - this is the foundation for everyone Contains everything that is common across all countries / all sites Once established and settled, will change less frequently than other 'higher' modules Encapsulates as many enterprise-wide integrations as possible Will provide means of code sharing therefore less development / testing - faster time to market Contains a 'reference' web application (described below) The next layer up could be multiple modules for each country (you could replace this with region if that makes more sense).  We'll define those modules as follows: Sits on top of the corporate foundation module Contains what is unique to all sites in a given country Responsible for managing any resource bundles for this country (to handle multiple languages) Overrides / replaces corporate integration points with any country-specific ones Finally, we will define what should be a fairly 'thin' (in terms of functionality) set of modules for each site as follows: Sits on top of the country it resides in module Contains what is unique for a given site within a given country Will mostly contain configuration, but could also define some unique functionality as well Contains one or more web applications The graphic below should help to indicate how these modules fit together: Web applications As described in the previous section, there are many opportunities for sharing (minimizing costs) as it relates to the code and configuration aspects of ATG modules.  Web applications are also contained within ATG modules, however, sharing web applications can be a bit more difficult because this is what the end customer actually sees, and since each site may have some degree of unique look & feel, sharing becomes more challenging.  One approach that can help is to define a 'reference' web application at the corporate foundation layer to act as a solid starting point for each site.  Here's a description of the 'reference' web application: Contains minimal / sample reference styling as this will mostly be addressed at the site level web app Focus on functionality - ensure that core functionality is revealed via this web application Each individual site can use this as a starting point There may be multiple types of web apps (i.e. B2C, B2B, etc) There are some techniques to share web application assets - i.e. multiple web applications, defined in the web.xml, and it's worth investigating, but is out of scope here. Reference infrastructure In this complex environment, it is assumed that there is not a single infrastructure for all countries and all sites.  It's more likely that different countries (or regions) could have their own solution for infrastructure.  In this case, it will be advantageous to define a reference infrastructure which contains all the hardware and software that make up the core environment.  Specifications and diagrams should be created to outline what this reference infrastructure looks like, as well as it's baseline cost and the incremental cost to scale up with volume.  Having some consistency in terms of infrastructure will save time and money as new countries / sites come online.  Here are some properties of the reference infrastructure: Standardized approach to setup of hardware Type and number of servers Defines application server, operating system, database, etc... - including vendor and specific versions Consistent naming conventions Provides a consistent base of terminology and understanding across environments Defines which ATG services run on which servers Production Staging BCC / Preview Each site can change as required to meet scale requirements Governance / organization It should be no surprise that the complex application we're talking about is backed by an equally complex organization.  One of the more challenging aspects of efficiently managing a series of complex applications is to ensure the proper level of governance and organization.  Here are some ideas and goals to work towards: Establish a committee to make enterprise-wide decisions that affect all sites Representation should be evenly distributed Should have a clear communication procedure Focus on high level business goals Evaluation of feature / function gaps and how that relates to ATG release schedule / roadmap Determine when to upgrade & ensure value will be realized Determine how to manage various levels of modules Who is responsible for maintaining corporate / country / site layers Determine a procedure for controlling what goes in the corporate foundation module Standardize on source code control, database, hardware, OS versions, J2EE app servers, development procedures, etc only use tested / proven versions - this is something that should be centralized so that every country / site does not have to worry about compatibility between versions Create a innovation team Quickly develop new features, perform proof of concepts All teams can benefit from their findings Summary At this point, it should be clear why the topics above (design, governance, organization, etc) are critical to being able to efficiently manage a complex application.  To summarize, it's all about competitive advantage...  You will need to reduce costs and improve time to market with the goal of providing a better experience for your end customers.  You can reduce cost by reducing development time, time allocated to testing (don't have to test the corporate foundation module over and over again - do it once), and optimizing operations.  With an efficient design, you can improve your time to market and your business will be more flexible  and agile.  Over time, you'll find that you're becoming more focused on offering functionality that is new to the market (creativity) and this will be rewarded - you're now a leader. In addition to the above, you'll realize soft benefits as well.  Your staff will be operating in a culture based on sharing.  You'll want to reward efforts to improve and enhance the foundation as this will benefit everyone.  This culture will inspire innovation, which can only lend itself to your competitive advantage.

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• Design patterns to avoiding breaking the SRP while performing heavy data logging

  - by Kazark

  A class that performs both computations and data logging seems to have at least two responsibilities. Given a system for which the specifications require heavy data logging, what kind of design patterns or architectural patterns can be used to avoid bloating all the classes with logging calls every time they compute something? The decorator pattern be used (e.g. Interpolator decorated to LoggingInterpolator), but it seems that would result in a situation hardly more desirable in which almost every major class would need to be decorated with logging.

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• A Perspective on Database Performance Tuning

  Fundamentally, database performance tuning is done for two basic reasons, to reduce response time and to reduce resource usage, both of which can apply for any given situation. Julian Stuhler looks at database performance tuning, and why it remains one of the most important topics for any DBA, developer or systems administrator.

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• SharePoint 2013 - Planet of the Apps - Now available

  - by Sahil Malik

  SharePoint 2010 Training: more information I am thrilled to announce the first bit of my many part series on SharePoint 2013. There are 17 more of these to follow, I will keep publishing them as time permits. The next one will be “Setting up your SP2013 Development Machine” – it will describe how to setup your SP2013 dev environment on a SINGLE MACHINE.Given what a memory piggie oink oink SP2013 is, there are plenty of tips in that work that I hope you will find useful. Presenting, SharePoint 2013 – Planet of the Apps Read full article ....

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• How do I add shadow mapping?

  - by Jasper Creyf

  How do I add shadow mapping? I don't care if it uses GLSL it just has to work. I have been searching on stencil shadows and shadow mapping, all the examples given did nothing, if you don't understand that it means not even a single shadow is even being rendered. If you know how to add stencil shadows or shadow mapping, then please show some java code and if you're using GLSL then please show the code for them too.

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