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• SQL Server devs–what source control system do you use, if any? (answer and maybe win free stuff)

  - by jamiet

  Recently I noticed a tweet from notable SQL Server author and community dude-at-large Steve Jones in which he asked how many SQL Server developers were putting their SQL Server source code (i.e. DDL) under source control (I’m paraphrasing because I can’t remember the exact tweet and Twitter’s search functionality is useless). The question surprised me slightly as I thought a more pertinent question would be “how many SQL Server developers are not using source control?” because I have been doing just that for many years now and I simply assumed that use of source control is a given in this day and age. Then I started thinking about it. “Perhaps I’m wrong” I pondered, “perhaps the SQL Server folks that do use source control in their day-to-day jobs are in the minority”. So, dear reader, I’m interested to know a little bit more about your use of source control. Are you putting your SQL Server code into a source control system? If so, what source control server software (e.g. TFS, Git, SVN, Mercurial, SourceSafe, Perforce) are you using? What source control client software are you using (e.g. TFS Team Explorer, Tortoise, Red Gate SQL Source Control, Red Gate SQL Connect, Git Bash, etc…)? Why did you make those particular software choices? Any interesting anecdotes to share in regard to your use of source control and SQL Server? To encourage you to contribute I have five pairs of licenses for Red Gate SQL Source Control and Red Gate SQL Connect to give away to what I consider to be the five best replies (“best” is totally subjective of course but this is my blog so my decision is final ), if you want to be considered don’t forget to leave contact details; email address, Twitter handle or similar will do. To start you off and to perhaps get the brain cells whirring, here are my answers to the questions above: Are you putting your SQL Server code into a source control system? As I think I’ve already said…yes. Always. If so, what source control server software (e.g. TFS, Git, SVN, Mercurial, SourceSafe, Perforce) are you using? I move around a lot between many clients so it changes on a fairly regular basis; my current client uses Team Foundation Server (aka TFS) and as part of a separate project is trialing the use of Team Foundation Service. I have used SVN extensively in the past which I am a fan of (I generally prefer it to TFS) and am trying to get my head around Git by using it for ObjectStorageHelper. What source control client software are you using (e.g. TFS Team Explorer, Tortoise, Red Gate SQL Source Control, Red Gate SQL Connect, Git Bash, etc…)? On my current project, Team Explorer. In the past I have used Tortoise to connect to SVN. Why did you make those particular software choices? I generally use whatever the client uses and given that I work with SQL Server I find that the majority of my clients use TFS, I guess simply because they are Microsoft development shops. Any interesting anecdotes to share in regard to your use of source control and SQL Server? Not an anecdote as such but I am going to share some frustrations about TFS. In many ways TFS is a great product because it integrates many separate functions (source control, work item tracking, build agents) into one whole and I’m firmly of the opinion that that is a good thing if for no reason other than being able to associate your check-ins with a work-item. However, like many people there are aspects to TFS source control that annoy me day-in, day-out. Chief among them has to be the fact that it uses a file’s read-only property to determine if a file should be checked-out or not and, if it determines that it should, it will happily do that check-out on your behalf without you even asking it to. I didn’t realise how ridiculous this was until I first used SVN about three years ago – with SVN you make any changes you wish and then use your source control client to determine which files have changed and thus be checked-in; the notion of “check-out” doesn’t even exist. That sounds like a small thing but you don’t realise how liberating it is until you actually start working that way. Hoping to hear some more anecdotes and opinions in the comments. Remember….free software is up for grabs! @jamiet 

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• Are technical books easy to read on the Kindle (or other small screens) [closed]

  - by Peter Recore

  Possible Duplicate: eBook editions of programming books I am considering getting a kindle or other e reader. (Kindle is my top choice for the eink vs lcd factor) I have been able to try reading fiction on a Kindle, and it seemed pretty nice, even with the small screen. However, most books I buy are actually technical books, which tend to have figures, code samples, and other odd things. How well do the various ereaders handle books like this? In particular, does the kindle render code samples or figures in an easy to read way?

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• Advices and strategies for browser compatibility on web applications into a corporate environment

  - by TiagoBrenck

  With the new CSS 3 and HTML 5 tecnology, the web applications gained a lot of new tools for a better UI(user interface) interaction, beautifull templates and even responsive layout to fit into tablets and smartphones. Within a corporate environment, those new tecnologies are required so the company can "follow" the IT evolution and their concurrent, but they also want that those new web applications supports old browsers. How to deal with this situation? By one side we are asked to follow the news and IT evolutions, create responsive layouts and use a lot of cool jQuery's plugins. And by the other side, we are asked to support old browsers that doesn't support those new responsive features, plugins or components. I would like advices and strategies to create "modern" web applications that are also supported on old browsers. How does your company deal with this situation? Is it possible to have the same web application running good and beauty on old browsers, and responsive, interactive on actual browsers?

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• Use Drive Mirroring for Instant Backup in Windows 7

  - by Trevor Bekolay

  Even with the best backup solution, a hard drive crash means you’ll lose a few hours of work. By enabling drive mirroring in Windows 7, you’ll always have an up-to-date copy of your data. Windows 7’s mirroring – which is only available in Professional, Enterprise, and Ultimate editions – is a software implementation of RAID 1, which means that two or more disks are holding the exact same data. The files are constantly kept in sync, so that if one of the disks fails, you won’t lose any data. Note that mirroring is not technically a backup solution, because if you accidentally delete a file, it’s gone from both hard disks (though you may be able to recover the file). As an additional caveat, having mirrored disks requires changing them to “dynamic disks,” which can only be read within modern versions of Windows (you may have problems working with a dynamic disk in other operating systems or in older versions of Windows). See this Wikipedia page for more information. You will need at least one empty disk to set up disk mirroring. We’ll show you how to mirror an existing disk (of equal or lesser size) without losing any data on the mirrored drive, and how to set up two empty disks as mirrored copies from the get-go. Mirroring an Existing Drive Click on the start button and type partitions in the search box. Click on the Create and format hard disk partitions entry that shows up. Alternatively, if you’ve disabled the search box, press Win+R to open the Run window and type in: diskmgmt.msc The Disk Management window will appear. We’ve got a small disk, labeled OldData, that we want to mirror in a second disk of the same size. Note: The disk that you will use to mirror the existing disk must be unallocated. If it is not, then right-click on it and select Delete Volume… to mark it as unallocated. This will destroy any data on that drive. Right-click on the existing disk that you want to mirror. Select Add Mirror…. Select the disk that you want to use to mirror the existing disk’s data and press Add Mirror. You will be warned that this process will change the existing disk from basic to dynamic. Note that this process will not delete any data on the disk! The new disk will be marked as a mirror, and it will starting copying data from the existing drive to the new one. Eventually the drives will be synced up (it can take a while), and any data added to the E: drive will exist on both physical hard drives. Setting Up Two New Drives as Mirrored If you have two new equal-sized drives, you can format them to be mirrored copies of each other from the get-go. Open the Disk Management window as described above. Make sure that the drives are unallocated. If they’re not, and you don’t need the data on either of them, right-click and select Delete volume…. Right-click on one of the unallocated drives and select New Mirrored Volume…. A wizard will pop up. Click Next. Click on the drives you want to hold the mirrored data and click Add. Note that you can add any number of drives. Click Next. Assign it a drive letter that makes sense, and then click Next. You’re limited to using the NTFS file system for mirrored drives, so enter a volume label, enable compression if you want, and then click Next. Click Finish to start formatting the drives. You will be warned that the new drives will be converted to dynamic disks. And that’s it! You now have two mirrored drives. Any files added to E: will reside on both physical disks, in case something happens to one of them. Conclusion While the switch from basic to dynamic disks can be a problem for people who dual-boot into another operating system, setting up drive mirroring is an easy way to make sure that your data can be recovered in case of a hard drive crash. Of course, even with drive mirroring, we advocate regular backups to external drives or online backup services. Similar Articles Productive Geek Tips Rebit Backup Software [Review]Disabling Instant Search in Outlook 2007Restore Files from Backups on Windows Home ServerSecond Copy 7 [Review]Backup Windows Home Server Folders to an External Hard Drive TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 VMware Workstation 7 Acronis Online Backup Windows Firewall with Advanced Security – How To Guides Sculptris 1.0, 3D Drawing app AceStock, a Tiny Desktop Quote Monitor Gmail Button Addon (Firefox) Hyperwords addon (Firefox) Backup Outlook 2010

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• How can I automatically change the system keyboard layout when plugging in an external keyboard?

  - by Andrew Bolster

  I have a US-Style laptop, which is fine, but I also have a UK-style Ergonomic USB keyboard. As such I usually have the US key layout set, but when I settle in at my desk and use the UK USB keyboard I find myself making stupid mistakes on symbols (normally a pretty good touch typist on either ergo or standard kbd). Can anyone think of a clean way of setting the keyboard layout based on the inferred layout/USBID of any plugged in Keyboard? Even having a custom setting such as adding a specific USB ID to a runtime script that checks if its plugged in or not. Can this be done without the user having to logout/in? I remember doing something similar with xorg.conf, but that required logout.

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• F# in ASP.NET, mathematics and testing

  - by DigiMortal

  Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#. F# and ASP.NET As I am ASP/ASP.NET MVP I am – of course – interested in how people use different languages and technologies with ASP.NET. C# MVP Tomáš Petrícek writes about developing ASP.NET MVC applications using F#. He also shows how to use LINQ To SQL in F# (using F# PowerPack) and provides sample solution and Visual Studio 2010 template for F# MVC web applications. You may also find interesting how you can create controllers in F#. Excellent work, Tomáš! Vladimir Matveev has interesting example about how to use F# and ApplicationHost class to process ASP.NET requests ouside of IIS. This is simple and very straight-forward example and I strongly suggest you to take a look at it. Very cool example is project Strom in Codeplex. Storm is web services testing tool that is fully written on F#. Take a look at this site because Codeplex offers also source code besides binaries. Math Functional languages are strong in fields like mathematics and physics. When I wrote my C# example about BigInteger class I found out that recursive version of Fibonacci algorithm in C# is not performing well. In same time I made same experiment on F# and in F# there were no performance problems with recursive version. You can find F# version of Fibonacci algorithm from Bob Palmer’s blog posting Fibonacci numbers in F#. Although golden spiral is useful for solving many problems I looked for some practical code example and found one. Kean Walmsley published in his Through the Interface blog very interesting posting Creating Fibonacci spirals in AutoCAD using F#. There are also other cool examples you may be interested in. Using numerical components by Extreme Optimization  it is possible to make some numerical integration (quadrature method) using F# (also C# example is available). fsharp.it introduces factorials calculation on F#. Robert Pickering has made very good work on programming The Game of Life in Silverlight and F# – I definitely suggest you to try out this example as it is very illustrative too. Who wants something more complex may take a look at Newton basin fractal example in F# by Jonathan Birge. Testing After some searching and surfing I found out that there is almost everything available for F# to write tests and test your F# code. FsCheck - FsCheck is a port of Haskell's QuickCheck. Important parts of the manual for using FsCheck is almost literally "adapted" from the QuickCheck manual and paper. Any errors and omissions are entirely my responsibility. FsTest - This project is designed to Language Oriented Programming constructs around unit testing and behavior testing in F#. The goal of this project is to create a Domain Specific Language for testing F# code in a way that makes sense for functional programming. FsUnit - FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework. xUnit.NET - xUnit.net is a developer testing framework, built to support Test Driven Development, with a design goal of extreme simplicity and alignment with framework features. It is compatible with .NET Framework 2.0 and later, and offers several runners: console, GUI, MSBuild, and Visual Studio integration via TestDriven.net, CodeRush Test Runner and Resharper. It also offers test project integration for ASP.NET MVC. Getting started Well, as a first thing you need Visual Studio 2010. Then take a look at these resources: F# samples @ MSDN Microsoft F# Developer Center @ MSDN F# Language Reference @ MSDN F# blog F# forums Real World Functional Programming: With Examples in F# and C# (Amazon) Happy F#-ing! :)

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• Anything Mouse Like Isn't Seen by Ubuntu 13.10

  - by belkinsa

  I have a upgraded 13.10 from 13.04 and today this issue of anything that is mouse-like is not seen by Ubuntu. The only input device that works is my Wacom Tablet and it's pen. I already checked for updates and have the latest updates for the Ubuntu system. Here is the lsusb output: Bus 002 Device 002: ID 04f2:b209 Chicony Electronics Co., Ltd Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 002: ID 056a:00b8 Wacom Co., Ltd Intuos4 4x6 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub This is issue a bug or how to fix it? I can't even use the Live USB of Ubuntu 13.10 to fix the issue. EDIT 1: Seems that Ubuntu isn't seeing the clicks done by a mouse if it's the Wacom tablet. EDIT 2: I think it's a bug but I need help to report it.

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• Installing Ubuntu 14.04 on macbook pro EFI

  - by user279771

  Macbook pro: mavericks, 5.2, graphics: nvidia geforce 9600M I followed the guides from here: https://help.ubuntu.com/community/UEFIBooting#Detect_.28U.29EFI_firmware_processor_architecture and http://www.rodsbooks.com/ubuntu-efi/. What I have is the following: /dev/sda apple partitions /boot / (root) swap When installing ubuntu, I did not install the boot loader during installation but did so in a chroot environment after installing grub-efi. I installed grub to /dev/sda1 (efi) which created the grub64.efi file in efi/ubuntu. This allows the refined boot manager to bring up grub and select ubuntu however, the graphics does not work. Even after adding nomodeset and removing quiet/splash from the kernel parameters. Any ideas on what could be wrong? To be clear, if I remove quiet/splash, I can see all the text startup messages being printed out however, the display manager doesn't appear to start (the screen stays black). Oddly enough though, the ubuntu startup sound can be heard.

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• UK Connected Systems User Group - Udi Dahan Event Topic change

  - by Michael Stephenson

  Hi Just wanted to get the word out about a change to the may user group event.  Udi Dahan will present a new topic which he has not presented in the UK before.  Details below. To register for this event please refer to: http://ukconnectedsystemsusergroup.org/UpcomingEvents.aspx Title: High Availability - A Contrarian View   Abstract: Many developers are aware of the importance of high availability, critically analyzing any single points of failure in the infrastructure. Those same developers rarely give a second thought to the periods of time when a system is being upgraded. Even if all the servers are running, most systems cannot function in-between versions. Yet with the increased pace of business, users are demanding ever more frequent releases. The poor maintenance programmers and system administrators are left holding the bag long after the architecture that sealed their fate was formulated. Join Udi for some different perspectives on high availability - architecture and methodology for the real world.

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• 2010 Goals Review

  - by andyleonard

  Introduction Earlier this year, I responded to Tim Ford's ( Blog / Twitter ) tag (in a post about 2010 Resolutions and Themeword ) with 2010 Themeword and Goals . Let's see how I did. Resolutions 1. I need to take better care of Andy. On this, I failed. I took even worse care of myself than before. I have to address this in 2011. You can help by pinging me on Twitter ( @AndyLeonard ) every day in 2011 and ask me if I've exercised today. 2. I want to continue to serve the SQL Server community in several...(read more)

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• How to Quickly Encrypt Removable Storage Devices with Ubuntu

  - by Chris Hoffman

  Ubuntu can quickly encrypt USB flash drives and external hard drives. You’ll be prompted for your passphrase each time you connect the drive to your computer – your private data will be secure, even if you misplace the drive. Ubuntu’s Disk Utility uses LUKS (Linux Unified Key Setup) encryption, which may not be compatible with other operating systems. However, the drive will be plug-and-play with any Linux system running the GNOME desktop. HTG Explains: What Is RSS and How Can I Benefit From Using It? HTG Explains: Why You Only Have to Wipe a Disk Once to Erase It HTG Explains: Learn How Websites Are Tracking You Online

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• Virus that makes all files and folders read-only filesystem on a usb drive

  - by ren florento

  Is there any way on how to remove a virus from Windows that makes the files and folders and the usb drive itself a read-only filesystem as this is an annoying one because the virus keeps copying itself as long as it sees a folder and keeps running which prevents you from creating and deleting files and folders from the usb drive and makes " mount -o remount,rw '/path' " ineffective ? btw i'm not really sure if it is a virus but what makes me think that it is a virus is for the reason the it creates a .exe file within every folder which was named after folder and it also immediately reverts to read-only filesystem which locks the files and folders even after executing the command " mount -o remount,rw '/path' ". i also think the virus is just running only within the usb drive as it is not affecting the folders on ubuntu. I could choose to reformat the usb drive as it only contains few important files but what concerns me is if such virus or whatever you may call it gets into my backup drives that contains many important files.Thanks for any help and advice you could give.

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• Dynamically creating astar node map by triangular polygonal map

  - by jett

  My game's map format uses a bunch of triangles to make up the platforms and terrain in 2d. Right now I can set up a 2d array of nodes for the astar algorithm that basically is a bunch of rectangles across the maps x and y that can be set to "wall" if the a* algorithm should try to go around it. However I want a function in the map loader to create the node overlay if the nodes are not specified. I was thinking if more than n percent of the a* rectangle overlaid on map was filled by polygons I could mark that entry in the array as "wall". However I'm stuck on how to do this(or even start) where/when the triangles can be overlapping and also of variable size.

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• Cloud Computing Architecture Patterns: Don’t Focus on the Client

  - by BuckWoody

  Normally I try to put topics in the positive in other words "Do this" not "Don't do that". Sometimes its clearer to focus on what *not* to do. Popular development processes often start with screen mockups, or user input descriptions. In a scale-out pattern like Cloud Computing on Windows Azure, that's the wrong place to start. Start with the Data    Instead, I recommend that you start with the data that a process requires. That data might be temporary or persisted, but starting with the data and its requirements helps to define not only the storage engine you need but also drives everything from security to the integrity of the application. For instance, assume the requirements show that the user must enter their phone number, and that this datum is used in a contact management system further down the application chain. For that datum, you can determine what data type you need (U.S. only or International?) the security requirements, whether it needs ACID compliance, how it will be searched, indexed and so on. From one small data point you can extrapolate out your options for storing and processing the data. Here's the interesting part, which begins to break the patterns that we've used for decades: all of the data doesn't have the same requirements. The phone number might be best suited for a list, or an element, or a string, with either BASE or ACID requirements, based on how it is used. That means we don't have to dump everything into XML, an RDBMS, a NoSQL engine, or a flat file exclusively. In fact, one record might use all of those depending on the use-case requirements. Next Is Data Management  With the data defined, we can move on to how to store the data. Again, the requirements now dictate whether we need a full relational calculus or set-based operations, or we can choose another method based on the requirements for the data. And breaking another pattern its OK to store in more than once, in more than one location. We do this all the time for reporting systems and Business Intelligence systems, so this is a pattern we need to think about even for OLTP data. Move to Data Transport How does the data get around? We can use a connection-based method, sending the data along a transport to the storage engine, but in some cases we may want to use a cache, a queue, the Service Bus, or Complex Event Processing. Finally, Data Processing Most RDBMS engines, NoSQL, and certainly Big Data engines not only store data, but can process and manipulate it as well. Its doubtful that you'll calculate that phone number right? Well, if you're the phone company, you most certainly will. And so we see that even once we've chosen the data type, storage and engine, the same element can have different computing requirements based on how it is used. Sure, We Need A Front-End At Some Point Not all data is entered by human hands in fact most data isn't. We don't really need a Graphical User Interface (GUI) we need some way for a GUI to get data into and out of the systems listed earlier.   But when we do need to allow users to enter or examine data, that should be left to the GUI that best fits the device the user has. Ever tried to use an application designed for a web browser on a phone? Or one designed for a tablet on a phone? Its usually quite painful. The siren song of "We'll just write one interface for all devices" is strong, and has beguiled many an unsuspecting architect. But they just don't work out.   Instead, focus on the data, its transport and processing. Create API calls or a message system that allows for resilient transport to the device or interface, and let it do what it does best. References Microsoft Architecture Journal:   http://msdn.microsoft.com/en-us/architecture/bb410935.aspx Patterns and Practices:   http://msdn.microsoft.com/en-us/library/ff921345.aspx Windows Azure iOS, Android, Windows 8 Mobile Devices SDK: http://www.windowsazure.com/en-us/develop/mobile/tutorials/get-started-ios/ Windows Azure Facebook SDK: http://ntotten.com/2013/03/14/using-windows-azure-mobile-services-with-the-facebook-sdk-for-windows-phone/

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• Mobile redirect strategy

  - by Kevin

  Looking for help on deciding how to redirect users to a mobile optimized version of my site (m.mysite.com). Looking at two methods: Server configuration (.htaccess or even varnish) Webapp (php) The problem I see with #1 is with the "view full site" link on the mobile site. If a user clicks that link and they go to mysite.com won't the server just redirect them back to m.mysite.com? For #2 I could create a cookie that is checked in addition to the user agent. Any suggestions/comments? Is there a better way to "remember" if the user clicked "visit full site"? Thanks, Kevin

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• Why lock-free data structures just aren't lock-free enough

  - by Alex.Davies

  Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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• Is there a “P” programming language? [closed]

  - by Synetech

  I’m wondering if anybody has made a programming language based on BCPL, named P. There was a language named B that was based on BCPL, followed of course by C, also based on BCPL. I’ve seen plenty of whimsically named programming languages, so I can’t help but be surprised if nobody made one called P. I checked the Wikipedia’s—not exactly comprehensive—list of programming languages, and while there are three languages named L (none of which are related to BCPL), there are none called P—in fact, it is one of the only letters not used as a name. (Google is useless for one-letter query terms.) Does anybody know if a P has been made, even as a lark. (Yes, I know about P#, but that is based on Prolog, not BCPL; there is one called P, but it is also not related to BCPL.)

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• Creating a Reverse Proxy with URL Rewrite for IIS

  - by OWScott

  There are times when you need to reverse proxy through a server. The most common example is when you have an internal web server that isn’t exposed to the internet, and you have a public web server accessible to the internet. If you want to serve up traffic from the internal web server, you can do this through the public web server by creating a tunnel (aka reverse proxy). Essentially, you can front the internal web server with a friendly URL, even hiding custom ports. For example, consider an internal web server with a URL of http://10.10.0.50:8111. You can make that available through a public URL like http://tools.mysite.com/ as seen in the following image. The URL can be made public or it can be used for your internal staff and have it password protected and/or locked down by IP address. This is easy to do with URL Rewrite and IIS. You will also need Application Request Routing (ARR) installed even though for a simple reverse proxy you won’t use most of ARR’s functionality. If you don’t already have URL Rewrite and ARR installed you can do so easily with the Web Platform Installer. A lot can be said about reverse proxies and many different situations and ways to route the traffic and handle different URL patterns. However, my goal here is to get you up and going in the easiest way possible. Then you can dig in deeper after you get the base configuration in place. URL Rewrite makes a reverse proxy very easy to set up. Note that the URL Rewrite Add Rules template doesn’t include Reverse Proxy at the server level. That’s not to say that you can’t create a server-level reverse proxy, but the URL Rewrite rules template doesn’t help you with that. Getting Started First you must create a website on your public web server that has the public bindings that you need. Alternately, you can use an existing site and route using conditions for certain traffic. After you’ve created your site then open up URL Rewrite at the site level. Using the “Add Rule(s)…” template that is opened from the right-hand actions pane, create a new Reverse Proxy rule. If you receive a prompt (the first time) that the proxy functionality needs to be enabled, select OK. This is telling you that a proxy can route traffic outside of your web server, which happens to be our goal in this case. Be aware that reverse proxy rules can be dangerous if you open sites from inside you network to the world, so just be aware of what you’re doing and why. The next and final step of the template asks a few questions. The first textbox asks the name of the internal web server. In our example, it’s 10.10.0.50:8111. This can be any URL, including a subfolder like internal.mysite.com/blog. Don’t include the http or https here. The template assumes that it’s not entered. You can choose whether to perform SSL Offloading or not. If you leave this checked then all requests to the internal server will be over HTTP regardless of the original web request. This can help with performance and SSL bindings if all requests are within a trusted network. If the network path between the two web servers is not completely trusted and safe then uncheck this. Next, the template enables you to create an outbound rule. This is used to rewrite links in the page to look like your public domain name rather than the internal domain name. Outbound rules have a lot of CPU overhead because the entire web content needs to be parsed and updated. However, if you need it, then it’s well worth the extra CPU hit on the web server. If you check the “Rewrite the domain names of the links in HTTP responses” checkbox then the From textbox will be filled in with what you entered for the inbound rule. You can enter your friendly public URL for the outbound rule. This will essentially replace any reference to 10.10.0.50:8111 (or whatever you enter) with tools.mysite.com in all <a>, <form>, and <img> tags on your site. That’s it! Well, there is a lot more that you can do, this but will give you the base configuration. You can now visit www.mysite.com on your public web server and it will serve up the site from your internal web server. You should see two rules show up; one inbound and one outbound. You can edit these, add conditions, and tweak them further as needed. One common issue that can occur without outbound rules has to do with compression. If you run into errors with the new proxied site, try turning off compression to confirm if that’s the issue. Here’s a link with details on how to deal with compression and outbound rules. I hope this was helpful to get started and to see how easy it is to create a simple reverse proxy using URL Rewrite for IIS.

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• Yet another ADF book - Oracle ADF Real World Developer’s Guide

  - by Chris Muir

  I'm happy to report that the number of ADF published books is expanding yet again, with this time Oracle's own Jobinesh Purushothaman publishing the Oracle ADF Real World Developer’s Guide.  I can remember the dim dark days when there was but just 1 Oracle book besides the documentation, so today it's great to have what I think might be the 7 or 8th ADF book publicly available, and not to forgot all our other technical docs too. Jobinesh has even published some extra chapters online that will give you a good taste of what to expect.  If you're interested in positive reviews, the ADF EMG already has it's first happy customer. Now to see if I can get Oracle to expense me a copy.

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• Autostart app with proper icon in unity launcher

  - by kyleN

  One can autostart an application such that it launches on session start with an xdg desktop file in ~/.config/autostart (or /etc/xdg/autostart). But my application (a python/gtk/webkit/html5 app) when autostarted has a unity (and a unity-2d) launcher icon that is a gray question mark, even though: when I find it in dash, the dash shows the icon I specify in my main desktop file (in /usr/share/applications) when I launch it from dash, the launcher shows the icon I specify in my main desktop file when I add it as a favorite, the launcher shows the proper icon There are two cases where I get the gray question mark icon: autostart launch from terminal (this use case is not essential though and doesn't involve the desktop file anyway: but should/does ubuntu have an xdg desktop file interpreter à la #!/usr/bin/desktop or something) So: what is needed such unity (3d/2d) launcher panel shows the icon specified in an autostart desktop file?

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• Ranking - an Introduction

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Ranking Ranking is quite common in the internet. Readers are asked to rank their latest reading by clicking on one of 5 (sometimes 10) stars. The number of stars is then converted to a number and the average number of stars as selected by all the readers is proudly (or shamefully) displayed for future readers. SharePoint 2007 lacked this feature altogether. SharePoint 2010 allows the users to rank items in a list or documents in a library (the two are actually the same because a library is actually a list). But in SP2010 the computation of the average is done later on a timer rather than on-the-spot as it should be. I suspect that the reason for this shortcoming is that they did not involve a mathematician! Let me explain. Ranking is kept in a related list. When a user rates a document the rank-list is added an item with the item id, the user name, and his number of stars. The fact that a user already ranked an item prevents him from ranking it again. This prevents the creator of the item from asking his mother to rank it a 5 and do it 753 times, thus stacking the ballot. Some systems will allow a user to change his rating and this will be done by updating the rank-list item. Now, when the timer kicks off, the list is spanned and for each item the rank-list items containing this id are summed up and divided by the number of votes thus yielding the new average. This is obviously very time consuming and very server intensive. In the 18th century an early actuary named James Dodson used what the great Augustus De Morgan (of De Morgan’s law) later named Commutation tables. The labor involved in computing a life insurance premium was staggering and also very error prone. Clerks with pencil and paper would multiply and add mountains of numbers to do the task. The more steps the greater the probability of error and the more expensive the process. Commutation tables created a “summary” of many steps and reduced the work 100 fold. So had Microsoft taken a lesson in the history of computation, they would have developed a much faster way for rating that may be done in real-time and is also 100 times faster and less CPU intensive. How do we do this? We use a form of commutation. We always keep the number of votes and the total of stars. One simple division gives us the average. So we write an event receiver. When a vote is added, we just add the stars to the total-stars and 1 to the number of votes. We then recomputed the average. When a vote is updated, we reduce the total by the old vote, increase it by the new vote and leave the number of votes the same. Again we do the division to get the new average. When a vote is deleted (highly unlikely and maybe even prohibited), we reduce the total by that vote and reduce the number of votes by 1… Gone are the days of spanning lists, counting items, and tallying votes and we have no need for a timer process to run it all. This is the first of a few treatises on ranking. Even though I discussed the math and the history thereof, in here I am only going to solve the presentation issue. I wanted to create the CSS and Jscript needed to display the stars, create the various effects like hovering and clicking (onmouseover, onmouseout, onclick, etc.) and I wanted to create a general solution with any number of stars. When I had it all done, I created the ranking game so that I could test it. The game is interesting in and on itself, so here it is (or go to the games page and select “rank the stars”). BTW, when you play it, look at the source code and see how it was all done.  Next, how the 5 stars are displayed in the New and Update forms. When the whole set of articles will be done, you’ll be able to create the complete solution. That’s all folks!

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• Developing iOS apps as web developer

  - by Keyo

  My Boss has sold a few 'iPhone apps' to clients, we are a web development shop. I have explained to him that I do not know the first thing about them, but it's such a powerful buzz-word and we need to meet clients expectations. I do have some experience in C, Java and Python which should help if I need to use objective-C. I have even done a few Android tutorials. These apps will more or less be HTML, in my mind they are not real apps, but faux apps which have the same functionality as the clients' websites. To me a real app is something that uses the phones hardware inputs and outputs, gps, accelerometer, speaker etc. What resources can I use to get up to speed iOS development and how to build apps in html. I have no idea where to begin.

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• A few meta questions about making flash games

  - by idan

  A few questions for a beginner game maker without an artist. Is there a site where flash game creators can download (and use) free art? I don't need character sprites but environments like trees, clouds, platforms, etc. Is there a site where a programmer can collaborate with an artist and a composer? (Even if so, the chances are low for a beginner with no portfolio to find an artist willing to collaborate, right?) Do you have recommended sites for asking action script questions (dedicated solely to flash?) Thanks!

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• Error:couldn't read file-Kernel panic

  - by Thanos

  I have just installed ubuntu 12.04.1. To be honest I had to run installation several times until it was finished fine. When I finally managed to install it properly, I power on the laptop and the grub shoed up! I selected ubuntu generic. It takes some time to load and when it does I get an error message stating that error: couldn't read file Press any key to continue If I press any button nothing happens. If a leave it there, in a short while there is a black screen loading which gives some weird messages [0.946710] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0) [0.946755] Pid: 1, comm: swapper/0 Not tainted 3.2.0-29-generic #46-Ubuntu [0.946792] Call Trace: [0.946831] [<ffffffff81640ec8>] panic+0x91/0x1a4 [0.946869] [<ffffffff81cfc01e>] mount_block_root+0xdc/0x18e [0.946909] [<ffffffff81002930>] ? populate_rootfs_wait+0x300/0x9d0 [0.946947] [<ffffffff81cfc257>] mount_root+0x54/0x59 [0.946982] [<ffffffff81cfcec9>] prepare_namespace+0x16d/0x1a6 [0.947019] [<ffffffff81cfbd63>] kernel_init+0x153/0x158 [0.947094] [<ffffffff81cfbc10>] ? start_kernel+0x3bd/0x3bd [0.947129] [<ffffffff81664030>] ? gs_change+0x13/0x13 The thing is that the laptop isn't mine. A friend tried to dual boot ubuntu alongside windows 7 but he didn't succeed. Ubuntu option was in grub, but when you tried to boot it rebooted from the start. So from a Live CD I erased ubuntu, started windows to check if something went wrong, and fortunately everything was OK. Windows started normally! So I tried to install ubuntu. Before installation was completed the installer crashed! I was afraid that he would lost windows, something that was true... At that point I tried to install windows but whichever distro(XP, 7{home, proffessional, ultimate},8) I tried it could never reach the end. So I tried to reinstall ubuntu but I was facing those weird messages. What can I do to move on? ______________________________________________________________________ EDIT1: I tried to check and fix(if possible) with GParted it took a lot of hours,although gparted displays only 01:14, I restarted the system and now I get not exactly the same messages. Numbers in braces [ ] are different [0.818189] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block (0,0) [0.818235] Pid: 1, comm: swapper/0 Not tainted 3.2.0-29-generic #46-Ubuntu [0.818272] Call Trace: [0.818312] [<ffffffff81640ec8>] panic+0x91/0x1a4 [0.818351] [<ffffffff81cfc01e>] mount_block_root+0xdc/0x18e [0.818391] [<ffffffff81002930>] ? populate_rootfs_wait+0x300/0x9d0 [0.818428] [<ffffffff81cfc257>] mount_root+0x54/0x59 [0.818464] [<ffffffff81cfcec9>] prepare_namespace+0x16d/0x1a6 [0.818501] [<ffffffff81cfbd63>] kernel_init+0x153/0x158 [0.818574] [<ffffffff81cfbc10>] ? start_kernel+0x3bd/0x3bd [0.818610] [<ffffffff81664030>] ? gs_change+0x13/0x13 What on earth is going on? ______________________________________________________________________ EDIT2: I forgot to mention that my friend gave a punch to his laptop during a game. After that his cooler became to make a weird noise so I checked and it is a bit tortuous but it is working. What I beleive must be wrong is that his HDD makes a weird noise while trying to load ubuntu, which means he might need a new HDD. Could that be true?

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• Microsoft Codename Houston

  - by kaleidoscope

  On one of the final talks about SQL Azure in Day 3 of PDC09, David Robinson, Senior PM on the Azure team, announced a project codenamed ‘Houston’ which is basically a Silverlight equivalent of SQL Server Management Studio. The concept comes from the SQL Azure being within the cloud, and if the only way to interact with it is by installing SSMS locally then it does not feel like a consistent story. From the limited preview, it only contains the basics but it clearly lets you create tables, stored procedures and views, edit them, even add data to tables in a grid view reminiscent of Microsoft Access. The UI was based around the standard ribbon bar, object window on the left and working pane on the right. As of now this tool is still pre-alpha and it seems like a basic tool that will facilitate rapid database development on cloud. When asked about general availability, no dates were given but calendar 2010 was indicated as the target. More information can be found at:      http://sqlfascination.com/2009/11/20/pdc-09-day-3-sql-azure-and-codename-houston-announcement/   Tinu, O

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