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• The Great Divorce

  - by BlackRabbitCoder

  I have a confession to make: I've been in an abusive relationship for more than 17 years now.  Yes, I am not ashamed to admit it, but I'm finally doing something about it. I met her in college, she was new and sexy and amazingly fast -- and I'd never met anything like her before.  Her style and her power captivated me and I couldn't wait to learn more about her.  I took a chance on her, and though I learned a lot from her -- and will always be grateful for my time with her -- I think it's time to move on. Her name was C++, and she so outshone my previous love, C, that any thoughts of going back evaporated in the heat of this new romance.  She promised me she'd be gentle and not hurt me the way C did.  She promised me she'd clean-up after herself better than C did.  She promised me she'd be less enigmatic and easier to keep happy than C was.  But I was deceived.  Oh sure, as far as truth goes, it wasn't a complete lie.  To some extent she was more fun, more powerful, safer, and easier to maintain.  But it just wasn't good enough -- or at least it's not good enough now. I loved C++, some part of me still does, it's my first-love of programming languages and I recognize its raw power, its blazing speed, and its improvements over its predecessor.  But with today's hardware, at speeds we could only dream to conceive of twenty years ago, that need for speed -- at the cost of all else -- has died, and that has left my feelings for C++ moribund. If I ever need to write an operating system or a device driver, then I might need that speed.  But 99% of the time I don't.  I'm a business-type programmer and chances are 90% of you are too, and even the ones who need speed at all costs may be surprised by how much you sacrifice for that.   That's not to say that I don't want my software to perform, and it's not to say that in the business world we don't care about speed or that our job is somehow less difficult or technical.  There's many times we write programs to handle millions of real-time updates or handle thousands of financial transactions or tracking trading algorithms where every second counts.  But if I choose to write my code in C++ purely for speed chances are I'll never notice the speed increase -- and equally true chances are it will be far more prone to crash and far less easy to maintain.  Nearly without fail, it's the macro-optimizations you need, not the micro-optimizations.  If I choose to write a O(n2) algorithm when I could have used a O(n) algorithm -- that can kill me.  If I choose to go to the database to load a piece of unchanging data every time instead of caching it on first load -- that too can kill me.  And if I cross the network multiple times for pieces of data instead of getting it all at once -- yes that can also kill me.  But choosing an overly powerful and dangerous mid-level language to squeeze out every last drop of performance will realistically not make stock orders process any faster, and more likely than not open up the system to more risk of crashes and resource leaks. And that's when my love for C++ began to die.  When I noticed that I didn't need that speed anymore.  That that speed was really kind of a lie.  Sure, I can be super efficient and pack bits in a byte instead of using separate boolean values.  Sure, I can use an unsigned char instead of an int.  But in the grand scheme of things it doesn't matter as much as you think it does.  The key is maintainability, and that's where C++ failed me.  I like to tell the other developers I work with that there's two levels of correctness in coding: Is it immediately correct? Will it stay correct? That is, you can hack together any piece of code and make it correct to satisfy a task at hand, but if a new developer can't come in tomorrow and make a fairly significant change to it without jeopardizing that correctness, it won't stay correct. Some people laugh at me when I say I now prefer maintainability over speed.  But that is exactly the point.  If you focus solely on speed you tend to produce code that is much harder to maintain over the long hall, and that's a load of technical debt most shops can't afford to carry and end up completely scrapping code before it's time.  When good code is written well for maintainability, though, it can be correct both now and in the future. And you know the best part is?  My new love is nearly as fast as C++, and in some cases even faster -- and better than that, I know C# will treat me right.  Her creators have poured hundreds of thousands of hours of time into making her the sexy beast she is today.  They made her easy to understand and not an enigmatic mess.  They made her consistent and not moody and amorphous.  And they made her perform as fast as I care to go by optimizing her both at compile time and a run-time. Her code is so elegant and easy on the eyes that I'm not worried where she will run to or what she'll pull behind my back.  She is powerful enough to handle all my tasks, fast enough to execute them with blazing speed, maintainable enough so that I can rely on even fairly new peers to modify my work, and rich enough to allow me to satisfy any need.  C# doesn't ask me to clean up her messes!  She cleans up after herself and she tries to make my life easier for me by taking on most of those optimization tasks C++ asked me to take upon myself.  Now, there are many of you who would say that I am the cause of my own grief, that it was my fault C++ didn't behave because I didn't pay enough attention to her.  That I alone caused the pain she inflicted on me.  And to some extent, you have a point.  But she was so high maintenance, requiring me to know every twist and turn of her vast and unrestrained power that any wrong term or bout of forgetfulness was met with painful reminders that she wasn't going to watch my back when I made a mistake.  But C#, she loves me when I'm good, and she loves me when I'm bad, and together we make beautiful code that is both fast and safe. So that's why I'm leaving C++ behind.  She says she's changing for me, but I have no interest in what C++0x may bring.  Oh, I'll still keep in touch, and maybe I'll see her now and again when she brings her problems to my door and asks for some attention -- for I always have a soft spot for her, you see.  But she's out of my house now.  I have three kids and a dog and a cat, and all require me to clean up after them, why should I have to clean up after my programming language as well?

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• Christmas in the Clouds

  - by andrewbrust

  I have been spending the last 2 weeks immersing myself in a number of Windows Azure and SQL Azure technologies.  And in setting up a new business (I’ll speak more about that in the future), I have also become a customer of Microsoft’s BPOS (Business Productivity Online Services).  In short, it has been a fortnight of Microsoft cloud computing. On the Azure side, I’ve looked, of course, at Web Roles and Worker Roles.  But I’ve also looked at Azure Storage’s REST API (including coding to it directly), I’ve looked at Azure Drive and the new VM Role; I’ve looked quite a bit at SQL Azure (including the project “Houston” Silverlight UI) and I’ve looked at SQL Azure labs’ OData service too. I’ve also looked at DataMarket and its integration with both PowerPivot and native Excel.  Then there’s AppFabric Caching, SQL Azure Reporting (what I could learn of it) and the Visual Studio tooling for Azure, including the storage of certificate-based credentials.  And to round it out with some user stuff, on the BPOS side, I’ve been working with Exchange Online, SharePoint Online and LiveMeeting. I have to say I like a lot of what I’ve been seeing.  Azure’s not perfect, and BPOS certainly isn’t either.  But there’s good stuff in all these products, and there’s a lot of value. Azure Goes Deep Most people know that Web and Worker roles put the platform in charge of spinning virtual machines up and down, and keeping them up to date. But you can go way beyond that now.  The still-in-beta VM Role gives you the power to craft the machine (much as does Amazon’s EC2), though it takes away the platform’s self-managing attributes.  It still spins instances up and down, making drive storage non-durable, but Azure Drive gives you the ability to store VHD files as blobs and mount them as virtual hard drives that are readable and writeable.  Whether with Azure Storage or SQL Azure, Azure does data.  And OData is everywhere.  Azure Table Storage supports an OData Interface.  So does SQL Azure and so does DataMarket (the former project “Dallas”).  That means that Azure data repositories aren’t just straightforward to provision and configure…they’re also easy to program against, from just about any programming environment, in a RESTful manner.  And for more .NET-centric implementations, Azure AppFabric caching takes the technology formerly known as “Velocity” and throws it up into the cloud, speeding data access even more. Snapping in Place Once you get the hang of it, this stuff just starts to work in a way that becomes natural to understand.  I wasn’t expecting that, and I was really happy to discover it. In retrospect, I am not surprised, because I think the various Azure teams are the center of gravity for Redmond’s innovation right now.  The products belie this and so do my observations of the product teams’ motivation and high morale.  It is really good to see this; Microsoft needs to lead somewhere, and they need to be seen as the underdog while doing so.  With Azure, both requirements are in place.   BPOS: Bad Acronym, Easy Setup BPOS is about products you already know; Exchange, SharePoint, Live Meeting and Office Communications Server.  As such, it’s hard not to be underwhelmed by BPOS.  Until you realize how easy it makes it to get all that stuff set up.  I would say that from sign-up to productive use took me about 45 minutes…and that included the time necessary to wrestle with my DNS provider, set up Outlook and my SmartPhone up to talk to the Exchange account, create my SharePoint site collection, and configure the Outlook Conferencing add-in to talk to the provisioned Live Meeting account. Never before did I think setting up my own Exchange mail could come anywhere close to the simplicity of setting up an SMTP/POP account, and yet BPOS actually made it faster.   What I want from my Azure Christmas Next Year Not everything about Microsoft’s cloud is good.  I close this post with a list of things I’d like to see addressed: BPOS offerings are still based on the 2007 Wave of Microsoft server technologies.  We need to get to 2010, and fast.  Arguably, the 2010 products should have been released to the off-premises channel before the on-premise sone.  Office 365 can’t come fast enough. Azure’s Internet tooling and domain naming, is scattered and confusing.  Deployed ASP.NET applications go to cloudapp.net; SQL Azure and Azure storage work off windows.net.  The Azure portal and Project Houston are at azure.com.  Then there’s appfabriclabs.com and sqlazurelabs.com.  There is a new Silverlight portal that replaces most, but not all of the HTML ones.  And Project Houston is Silvelright-based too, though separate from the Silverlight portal tooling. Microsoft is the king off tooling.  They should not make me keep an entire OneNote notebook full of portal links, account names, access keys, assemblies and namespaces and do so much CTRL-C/CTRL-V work.  I’d like to see more project templates, have them automatically reference the appropriate assemblies, generate the right using/Imports statements and prime my config files with the right markup.  Then I want a UI that lets me log in with my Live ID and pick the appropriate project, database, namespace and key string to get set up fast. Beta programs, if they’re open, should onboard me quickly.  I know the process is difficult and everyone’s going as fast as they can.  But I don’t know why it’s so difficult or why it takes so long.  Getting developers up to speed on new features quickly helps popularize the platform.  Make this a priority. Make Azure accessible from the simplicity platforms, i.e. ASP.NET Web Pages (Razor) and LightSwitch.  Support .NET 4 now.  Make WebMatrix, IIS Express and SQL Compact work with the Azure development fabric. Have HTML helpers make Azure programming easier.  Have LightSwitch work with SQL Azure and not require SQL Express.  LightSwitch has some promising Azure integration now.  But we need more.  WebMatrix has none and that’s just silly, now that the Extra Small Instance is being introduced. The Windows Azure Platform Training Kit is great.  But I want Microsoft to make it even better and I want them to evangelize it much more aggressively.  There’s a lot of good material on Azure development out there, but it’s scattered in the same way that the platform is.   The Training Kit ties a lot of disparate stuff together nicely.  Make it known. Should Old Acquaintance Be Forgot All in all, diving deep into Azure was a good way to end the year.  Diving deeper into Azure should a great way to spend next year, not just for me, but for Microsoft too.

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• NUMA-aware placement of communication variables

  - by Dave

  For classic NUMA-aware programming I'm typically most concerned about simple cold, capacity and compulsory misses and whether we can satisfy the miss by locally connected memory or whether we have to pull the line from its home node over the coherent interconnect -- we'd like to minimize channel contention and conserve interconnect bandwidth. That is, for this style of programming we're quite aware of where memory is homed relative to the threads that will be accessing it. Ideally, a page is collocated on the node with the thread that's expected to most frequently access the page, as simple misses on the page can be satisfied without resorting to transferring the line over the interconnect. The default "first touch" NUMA page placement policy tends to work reasonable well in this regard. When a virtual page is first accessed, the operating system will attempt to provision and map that virtual page to a physical page allocated from the node where the accessing thread is running. It's worth noting that the node-level memory interleaving granularity is usually a multiple of the page size, so we can say that a given page P resides on some node N. That is, the memory underlying a page resides on just one node. But when thinking about accesses to heavily-written communication variables we normally consider what caches the lines underlying such variables might be resident in, and in what states. We want to minimize coherence misses and cache probe activity and interconnect traffic in general. I don't usually give much thought to the location of the home NUMA node underlying such highly shared variables. On a SPARC T5440, for instance, which consists of 4 T2+ processors connected by a central coherence hub, the home node and placement of heavily accessed communication variables has very little impact on performance. The variables are frequently accessed so likely in M-state in some cache, and the location of the home node is of little consequence because a requester can use cache-to-cache transfers to get the line. Or at least that's what I thought. Recently, though, I was exploring a simple shared memory point-to-point communication model where a client writes a request into a request mailbox and then busy-waits on a response variable. It's a simple example of delegation based on message passing. The server polls the request mailbox, and having fetched a new request value, performs some operation and then writes a reply value into the response variable. As noted above, on a T5440 performance is insensitive to the placement of the communication variables -- the request and response mailbox words. But on a Sun/Oracle X4800 I noticed that was not the case and that NUMA placement of the communication variables was actually quite important. For background an X4800 system consists of 8 Intel X7560 Xeons . Each package (socket) has 8 cores with 2 contexts per core, so the system is 8x8x2. Each package is also a NUMA node and has locally attached memory. Every package has 3 point-to-point QPI links for cache coherence, and the system is configured with a twisted ladder "mobius" topology. The cache coherence fabric is glueless -- there's not central arbiter or coherence hub. The maximum distance between any two nodes is just 2 hops over the QPI links. For any given node, 3 other nodes are 1 hop distant and the remaining 4 nodes are 2 hops distant. Using a single request (client) thread and a single response (server) thread, a benchmark harness explored all permutations of NUMA placement for the two threads and the two communication variables, measuring the average round-trip-time and throughput rate between the client and server. In this benchmark the server simply acts as a simple transponder, writing the request value plus 1 back into the reply field, so there's no particular computation phase and we're only measuring communication overheads. In addition to varying the placement of communication variables over pairs of nodes, we also explored variations where both variables were placed on one page (and thus on one node) -- either on the same cache line or different cache lines -- while varying the node where the variables reside along with the placement of the threads. The key observation was that if the client and server threads were on different nodes, then the best placement of variables was to have the request variable (written by the client and read by the server) reside on the same node as the client thread, and to place the response variable (written by the server and read by the client) on the same node as the server. That is, if you have a variable that's to be written by one thread and read by another, it should be homed with the writer thread. For our simple client-server model that means using split request and response communication variables with unidirectional message flow on a given page. This can yield up to twice the throughput of less favorable placement strategies. Our X4800 uses the QPI 1.0 protocol with source-based snooping. Briefly, when node A needs to probe a cache line it fires off snoop requests to all the nodes in the system. Those recipients then forward their response not to the original requester, but to the home node H of the cache line. H waits for and collects the responses, adjudicates and resolves conflicts and ensures memory-model ordering, and then sends a definitive reply back to the original requester A. If some node B needed to transfer the line to A, it will do so by cache-to-cache transfer and let H know about the disposition of the cache line. A needs to wait for the authoritative response from H. So if a thread on node A wants to write a value to be read by a thread on node B, the latency is dependent on the distances between A, B, and H. We observe the best performance when the written-to variable is co-homed with the writer A. That is, we want H and A to be the same node, as the writer doesn't need the home to respond over the QPI link, as the writer and the home reside on the very same node. With architecturally informed placement of communication variables we eliminate at least one QPI hop from the critical path. Newer Intel processors use the QPI 1.1 coherence protocol with home-based snooping. As noted above, under source-snooping a requester broadcasts snoop requests to all nodes. Those nodes send their response to the home node of the location, which provides memory ordering, reconciles conflicts, etc., and then posts a definitive reply to the requester. In home-based snooping the snoop probe goes directly to the home node and are not broadcast. The home node can consult snoop filters -- if present -- and send out requests to retrieve the line if necessary. The 3rd party owner of the line, if any, can respond either to the home or the original requester (or even to both) according to the protocol policies. There are myriad variations that have been implemented, and unfortunately vendor terminology doesn't always agree between vendors or with the academic taxonomy papers. The key is that home-snooping enables the use of a snoop filter to reduce interconnect traffic. And while home-snooping might have a longer critical path (latency) than source-based snooping, it also may require fewer messages and less overall bandwidth. It'll be interesting to reprise these experiments on a platform with home-based snooping. While collecting data I also noticed that there are placement concerns even in the seemingly trivial case when both threads and both variables reside on a single node. Internally, the cores on each X7560 package are connected by an internal ring. (Actually there are multiple contra-rotating rings). And the last-level on-chip cache (LLC) is partitioned in banks or slices, which with each slice being associated with a core on the ring topology. A hardware hash function associates each physical address with a specific home bank. Thus we face distance and topology concerns even for intra-package communications, although the latencies are not nearly the magnitude we see inter-package. I've not seen such communication distance artifacts on the T2+, where the cache banks are connected to the cores via a high-speed crossbar instead of a ring -- communication latencies seem more regular.

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• Corsair Hackers Reboot

  It wasn't easy for me to attend but it was absolutely worth to go. The Linux User Group of Mauritius (LUGM) organised another get-together for any open source enthusiast here on the island. Strangely named "Corsair Hackers Reboot" but it stands for a positive cause: "Corsair Hackers Reboot Event A collaborative activity involving LUGM, UoM Computer Club, Fortune Way Shopping Mall and several geeks from around the island, striving to put FOSS into homes & offices. The public is invited to discover and explore Free Software & Open Source." And it was a good opportunity for me and the kids to visit the east coast of Mauritius, too. Perfect timing It couldn't have been better... Why? Well, for two important reasons (in terms of IT): End of support for Microsoft Windows XP - 08.04.2014 Release of Ubuntu 14.04 Long Term Support - 17.04.2014 Quite funnily, those two IT dates weren't the initial reasons and only during the weeks of preparations we put those together. And therefore it was even more positive to promote the use of Linux and open source software in general to a broader audience. Getting there ... Thanks to the new motor way M3 and all the additional road work which has been completed recently it was very simple to get across the island in a very quick and relaxed manner. Compared to my trips in the early days of living in Mauritius (and riding on a scooter) it was very smooth and within less than an hour we hit Centrale de Flacq. Well, being in the city doesn't necessarily mean that one has arrived at the destination. But thanks to modern technology I had a quick look on Google Maps, and we finally managed to get a parking behind the huge bus terminal in Flacq. From there it was just a short walk to Fortune Way. The children were trying to count the number of buses... Well, lots and lots of buses - really impressive actually. What was presented? There were different areas set up. Right at the entrance one's attention was directly drawn towards the elevated hacker's stage. Similar to rock stars performing their gig there was bunch of computers, laptops and networking equipment in order to cater the right working conditions for coding/programming challenge(s) on the one hand and for the pen-testing or system hacking competition on the other hand. Personally, I was very impresses that actually Nitin took care of the pen-testing competition. He hardly started one year back with Linux in general, and Kali Linux specifically. Seeing his personal development from absolute newbie to a decent Linux system administrator within such a short period of time, is really impressive. His passion to open source software made him a living. Next, clock-wise seen, was the Kid's Corner with face-painting as the main attraction. Additionally, there were numerous paper print outs to colour. Plus a decent workstation with the educational suite GCompris. Of course, my little ones were into that. They already know GCompris since a while as they are allowed to use it on an IGEL thin client terminal here at home. To simplify my life, I set up GCompris as full-screen guest session on the server, and they can pass the login screen without any further obstacles. And because it's a thin client hooked up to a XDMCP remote session I don't have to worry about the hardware on their desk, too. The next section was the main attraction of the event: BYOD - Bring Your Own Device Well, compared to the usual context of BYOD the corsairs had a completely different intention. Here, you could bring your own laptop and a team of knowledgeable experts - read: geeks and so on - offered to fully convert your system on any Linux distribution of your choice. And even though I came later, I was told that the USB pen drives had been in permanent use. From being prepared via dd command over launching LiveCD session to finally installing a fresh Linux system on bare metal. Most interestingly, I did a similar job already a couple of months ago, while upgrading an existing Windows XP system to Xubuntu 13.10. So far, the female owner is very happy and enjoys her system almost every evening to go shopping online, checking mails, and reading latest news from the Anime world. Back to the Hackers event, Ish told me that they managed approximately 20 conversion during the day. Furthermore, Ajay and others gladly assisted some visitors with some tricky issues and by the end of the day you can call is a success. While I was around, there was a elderly male visitor that got a full-fledged system conversion to a Linux system running completely in French language. A little bit more to the centre it was Yasir's turn to demonstrate his Arduino hardware that he hooked up with an experimental electrical circuit board connected to an LCD matrix display. That's the real spirit of hacking, and he showed some minor adjustments on the fly while demo'ing the system. Also, very interesting there was a thermal sensor around. Personally, I think that platforms like the Arduino as well as the Raspberry Pi have a great potential at a very affordable price in order to bring a better understanding of electronics as well as computer programming to a broader audience. It would be great to see more of those experiments during future activities. And last but not least there were a small number of vendors. Amongst them was Emtel - once again as sponsor of the general internet connectivity - and another hardware supplier from Riche Terre shopping mall. They had a good collection of Android related gimmicks, like a autonomous web cam that can convert any TV with HDMI connector into an online video chat system given WiFi. It's actually kind of awesome to have a Skype or Google hangout video session on the big screen rather than on the laptop. Some pictures of the event LUGM: Great conversations on Linux, open source and free software during the Corsair Hackers Reboot LUGM: Educational workstation running GCompris suite attracted the youngest attendees of the day. Of course, face painting had to be done prior to hacking... LUGM: Nadim demoing some Linux specifics to interested visitors. Everyone was pretty busy during the whole day LUGM: The hacking competition, here pen-testing a wireless connection and access point between multiple machines LUGM: Well prepared workstations to be able to 'upgrade' visitors' machines to any Linux operating system Final thoughts Gratefully, during the preparations of the event I was invited to leave some comments or suggestions, and the team of the LUGM did a great job. The outdoor banner was a eye-catcher, the various flyers and posters for the event were clearly written and as far as I understood from the quick chats I had with Ish, Nadim, Nitin, Ajay, and of course others all were very happy about the event execution. Great job, LUGM! And I'm already looking forward to the next Corsair Hackers Reboot event ... Crossing fingers: Very soon and hopefully this year again :) Update: In the media The event had been announced in local media, too. L'Express: Salon informatique: Hacking Challenge à Flacq

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• PostSharp, Obfuscation, and IL

  - by Simon Cooper

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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• PostSharp, Obfuscation, and IL

  - by simonc

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day! Cross posted from Simple Talk.

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• Super constructor must be a first statement in Java constructor [closed]

  - by Val

  I know the answer: "we need rules to prevent shooting into your own foot". Ok, I make millions of programming mistakes every day. To be prevented, we need one simple rule: prohibit all JLS and do not use Java. If we explain everything by "not shooting your foot", this is reasonable. But there is not much reason is such reason. When I programmed in Delphy, I always wanted the compiler to check me if I read uninitializable. I have discovered myself that is is stupid to read uncertain variable because it leads unpredictable result and is errorenous obviously. By just looking at the code I could see if there is an error. I wished if compiler could do this job. It is also a reliable signal of programming error if function does not return any value. But I never wanted it do enforce me the super constructor first. Why? You say that constructors just initialize fields. Super fields are derived; extra fields are introduced. From the goal point of view, it does not matter in which order you initialize the variables. I have studied parallel architectures and can say that all the fields can even be assigned in parallel... What? Do you want to use the unitialized fields? Stupid people always want to take away our freedoms and break the JLS rules the God gives to us! Please, policeman, take away that person! Where do I say so? I'm just saying only about initializing/assigning, not using the fields. Java compiler already defends me from the mistake of accessing notinitialized. Some cases sneak but this example shows how this stupid rule does not save us from the read-accessing incompletely initialized in construction: public class BadSuper { String field; public String toString() { return "field = " + field; } public BadSuper(String val) { field = val; // yea, superfirst does not protect from accessing // inconstructed subclass fields. Subclass constr // must be called before super()! System.err.println(this); } } public class BadPost extends BadSuper { Object o; public BadPost(Object o) { super("str"); this. o = o; } public String toString() { // superconstructor will boom here, because o is not initialized! return super.toString() + ", obj = " + o.toString(); } public static void main(String[] args) { new BadSuper("test 1"); new BadPost(new Object()); } } It shows that actually, subfields have to be inilialized before the supreclass! Meantime, java requirement "saves" us from writing specializing the class by specializing what the super constructor argument is, public class MyKryo extends Kryo { class MyClassResolver extends DefaultClassResolver { public Registration register(Registration registration) { System.out.println(MyKryo.this.getDepth()); return super.register(registration); } } MyKryo() { // cannot instantiate MyClassResolver in super super(new MyClassResolver(), new MapReferenceResolver()); } } Try to make it compilable. It is always pain. Especially, when you cannot assign the argument later. Initialization order is not important for initialization in general. I could understand that you should not use super methods before initializing super. But, the requirement for super to be the first statement is different. It only saves you from the code that does useful things simply. I do not see how this adds safety. Actually, safety is degraded because we need to use ugly workarounds. Doing post-initialization, outside the constructors also degrades safety (otherwise, why do we need constructors?) and defeats the java final safety reenforcer. To conclude Reading not initialized is a bug. Initialization order is not important from the computer science point of view. Doing initalization or computations in different order is not a bug. Reenforcing read-access to not initialized is good but compilers fail to detect all such bugs Making super the first does not solve the problem as it "Prevents" shooting into right things but not into the foot It requires to invent workarounds, where, because of complexity of analysis, it is easier to shoot into the foot doing post-initialization outside the constructors degrades safety (otherwise, why do we need constructors?) and that degrade safety by defeating final access modifier When there was java forum alive, java bigots attecked me for these thoughts. Particularly, they dislaked that fields can be initialized in parallel, saying that natural development ensures correctness. When I replied that you could use an advanced engineering to create a human right away, without "developing" any ape first, and it still be an ape, they stopped to listen me. Cos modern technology cannot afford it. Ok, Take something simpler. How do you produce a Renault? Should you construct an Automobile first? No, you start by producing a Renault and, once completed, you'll see that this is an automobile. So, the requirement to produce fields in "natural order" is unnatural. In case of alarmclock or armchair, which are still chair and clock, you may need first develop the base (clock and chair) and then add extra. So, I can have examples where superfields must be initialized first and, oppositely, when they need to be initialized later. The order does not exist in advance. So, the compiler cannot be aware of the proper order. Only programmer/constructor knows is. Compiler should not take more responsibility and enforce the wrong order onto programmer. Saying that I cannot initialize some fields because I did not ininialized the others is like "you cannot initialize the thing because it is not initialized". This is a kind of argument we have. So, to conclude once more, the feature that "protects" me from doing things in simple and right way in order to enforce something that does not add noticeably to the bug elimination at that is a strongly negative thing and it pisses me off, altogether with the all the arguments to support it I've seen so far. It is "a conceptual question about software development" Should there be the requirement to call super() first or not. I do not know. If you do or have an idea, you have place to answer. I think that I have provided enough arguments against this feature. Lets appreciate the ones who benefit form it. Let it just be something more than simple abstract and stupid "write your own language" or "protection" kind of argument. Why do we need it in the language that I am going to develop?

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• UNIX - mount: only root can do that

  - by Travesty3

  I need to allow a non-root user to mount/unmount a device. I am a total noob when it comes to UNIX, so please dumb it down for me. I've been looking all over teh interwebz to find an answer and it seems everyone is giving the same one, which is to modify /etc/fstab to include that device with the 'user' option (or 'users', tried both). Cool, well I did that and it still says "mount: only root can do that". Here are the contents of my fstab: # /etc/fstab: static file system information. # # Use 'vol_id --uuid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # proc /proc proc defaults 0 0 # / was on /dev/mapper/minicc-root during installation UUID=1a69f02a-a049-4411-8c57-ff4ebd8bb933 / ext3 relatime,errors=remount-ro 0 1 # /boot was on /dev/sda5 during installation UUID=038498fe-1267-44c4-8788-e1354d71faf5 /boot ext2 relatime 0 2 # swap was on /dev/mapper/minicc-swap_1 during installation UUID=0bb583aa-84a8-43ef-98c4-c6cb25d20715 none swap sw 0 0 /dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0 /dev/scd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0 /dev/sdb1 /mnt/sdcard auto auto,user,rw,exec 0 0 My thumb drive partition shows up as /dev/sdb1. I'm pretty sure my fstab is set up OK, but everyone on the other posts seems to fail to mention how they actually call the 'mount' command once this entry is in the fstab file. I think this is where my problem may be. The command I use to mount the drive is: $ mount /dev/sdb1 /mnt/sdcard. /bin/mount is owned by root and is in the root group and has 4755 permissions. /bin/umount is owned by root and is in the root group and has 4755 permissions. /mnt/sdcard is owned by me and is in one of my groups and has 0755 permissions. My mount command works fine if I use sudo, but I need to be able to do this without sudo (need to be able to do it from a PHP script using shell_exec). Any suggestions? Sorry for making you read so much...just trying to get as much info in the initial post as possible to preemptively answer questions about configuration stuff. If I missed anything tho, ask away. Thanks! -Travis

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• Uninstall php and nginx or fix setup

  - by jreed121

  First off, I'm a huge linux noob - sorry... I'm trying to setup nginx with php-fpm on debian and I'm pretty sure that I've completely screwed it up. nginx seems to be running fine because I can it it from a web browser and it load the stock "Welcome to nginx!" page. I'm not so sure about php-fpm though. When I try something like # restart php-fpm I get: bash: restart: command not found First off php-fpm some how got installed as php5-fpm when I do root@server:/etc/init.d# ls, which seems to contradict every tutorial and help doc I've read (supposed to be 'php-fpm'). I can restart it with this: service php5-fpm restart And just enter the package name 'php5-fpm' I get this: root@server:~# php5-fpm [17-Nov-2012 23:15:36] NOTICE: PHP message: PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20100525/suhosin.so' - /usr/lib/php5/20100525/suhosin.so: cannot open shared object file: No such file or directory in Unknown on line 0 [17-Nov-2012 23:15:36] ERROR: An another FPM instance seems to already listen on /var/run/php5-fpm.sock [17-Nov-2012 23:15:36] ERROR: FPM initialization failed The root for nginx is /usr/share/nginx/html, when I try to navigate to a .php file in there with my web browser, it tries to download the file instead of interpret it. I would like this folder to be in my user's home directory ie: /home/administrator/www or /home/nginx/www. I know in order to do this I need to modify nginx.conf, but I find that configuration file difficult to understand. I suppose the fact that my .php scripts aren't being handled is my bigger problem anyways. When I try to see what running on port 9000 (php-fpm default port) with lsof -i :9000 it returns nothing - I guess indicating that it isn't listening. then I head over to vim /etc/php5/fpm/php-fpm.conf and there is no where to designate a port number. So should I just uninstall everything and start from scratch? If so, how do I clean it all up? Any suggestions for a tutorial once I'm ready to try again? Should I attempt to troubleshoot this mess? If so where should I start? Sorry guys, I'm feeling pretty stupid and lost right now. I'm not sure what my next steps are in trying to resolve this issue are. I realize that this is a horrible question for this type of Q&A site, but I'd really appreciate any guidance.

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• Computer experiencing slowdowns and lockups despite low cpu useage

  - by user157145

  my setup i5-2300 nvidia gtx 550 ti 6 gigs ram 600 w ocz modular psu recently reformatted and already experiencing drastic slowdown as soon as windows comes up, including repeated lockups with multiple various programs reporting that they are not responsive, then recovering after 10-30 seconds. ive checked memory and hard drive both of which come out fine. despite my plethura of worthless antiviral software im forced to assume that my illicit downloading practices have lead me into some comp trouble that i cant seem to determine. i have used ccleaner, search and destroy and malware bytes, all of which have found nothing to indicate what is causing this massive slowdown. in addition according to my resource manager my computer is operating at a load of only 30-50 percent CPU useage and 60 ram useage but taking 5-10 seconds to load files and open folders, and repeated lockups of multiple programs, especially firefox which seems to go unresponsive every 2-3 minutes. any help would be appreciated, i used a program called OTL by old timer, but cant make any sense of the results i was given. any help or suggestions would be appreciated, thank you for taking the time to read this i have avast but it didnt even find anything when i had it do a full system scan, so im thinking its clueless(also nortons, avg, and ad-aware). i also have mse but it has yet to complete a full scan it takes so long (i left it on last night but when i woke up my computer had a problem and had to restart). my hard drive has 300 gigs out of 1tb open and i already used hd tune pro, which said my harddrive was fine and its not a ssd. also im a noob at comps and only have the hd that is currently inside the computer in addition im not sure if studdering is the issue im suffering. my problem is that during my typing of these responses firefox has gone "not responsive" at least 5 times, each for times of about 5-10 seconds. when i try to control alt delete to bring up windows task manager it took 20 seconds. essentially its that my computer goes super slow at bringing up anything, or taking any action whatsoever that opens a program or file and has repeated incidents where i cant even click on whatever im trying to do because it locks up. the confusing thing about these incidents is that its right after restarting where there are minimal programs running and the computer and memory load is light.

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• Postfix issues sending mail to addresses under domain located on server

  - by iamthewit

  I recently installed virtualmin on my nice shiny new rackspace cloud. Everything went seemlessly but I've been having some issues getting emails to send properly. The problem seems to be that the server can not send mail to email addresses where the domain is owned by my server. For example, on my server I run multiple virtual domains, lets call this one test.com. When I run the mail command from shell (mail [email protected]) I get the following back from my maillog: Oct 6 14:55:18 test postfix/pickup[8737]: DC1131612CC: uid=0 from= Oct 6 14:55:18 test postfix/cleanup[8769]: DC1131612CC: [email protected] Oct 6 14:55:18 test postfix/qmgr[8738]: DC1131612CC: [email protected], size=353, nrcpt=1 (queue active) Oct 6 14:55:18 test postfix/error[8771]: DC1131612CC: [email protected], relay=none, delay=0, delays=0/0/0/0, dsn=5.0.0, status=bounced (User unknown in virtual alias table) Oct 6 14:55:18 test postfix/cleanup[8769]: DD07D1612D1: [email protected] Oct 6 14:55:18 test postfix/bounce[8772]: DC1131612CC: sender non-delivery notification: DD07D1612D1 Oct 6 14:55:18 test postfix/qmgr[8738]: DD07D1612D1: from=<, size=2268, nrcpt=1 (queue active) Oct 6 14:55:18 test postfix/qmgr[8738]: DC1131612CC: removed Oct 6 14:55:18 test postfix/local[8773]: DD07D1612D1: [email protected], relay=local, delay=0.03, delays=0/0/0/0.03, dsn=2.0.0, status=sent (delivered to command: /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME) Oct 6 14:55:18 test postfix/qmgr[8738]: DD07D1612D1: removed when I run mail [email protected] the message is sent and received perfectly fine. I'm a bit of a noob when it comes to servers, but I pick things up fairly quickly, so please excuse any incorrect terminology and my general noobiness. Any help would be greatly appreciated, I've been googling for quite a while but I haven't found a solution yet, I'll add a copy of my main.cf file in a response below cheers guys here is the reformatted postconf, do you want the reformatted main.cf file too, or is this enough? alias_database = hash:/etc/postfix/aliases alias_maps = hash:/etc/postfix/aliases broken_sasl_auth_clients = yes command_directory = /usr/sbin config_directory = /etc/postfix daemon_directory = /usr/libexec/postfix debug_peer_level = 2 home_mailbox = Maildir/ html_directory = no mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME mailq_path = /usr/bin/mailq.postfix manpage_directory = /usr/share/man myhostname = server.test.com newaliases_path = /usr/bin/newaliases.postfix readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES sample_directory = /usr/share/doc/postfix-2.3.3/samples sender_bcc_maps = hash:/etc/postfix/bcc sendmail_path = /usr/sbin/sendmail.postfix setgid_group = postdrop smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination smtpd_sasl_auth_enable = yes smtpd_sasl_security_options = noanonymous unknown_local_recipient_reject_code = 550 virtual_alias_maps = hash:/etc/postfix/virtual

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• Which hardware to VM ratio for Build-Server virtualization?

  - by Martin

  Let's start with saying that I'm a total noob wrt. to server virtualization. That is, I use VMs often during development, but they're simple desktop machine things for me. Now to my problem: We have two (physical) build servers, one master, one slave running Jenkins to do daily tasks and build (Visual C++ Builds) our release packages for our software. As such these machines are critical to our company, because we do lot's releases and without a controlled environment to create them, we can't ship fixes. (And currently there's no proper backup of these machines in place, because they do not hold any data as such - it just would be a major pain to setup them again should they go bust. (But setting up backup that I'd know would work in case of HW failure would even be more pain, so we have skipped that until now.)) Therefore (and for scaling purposes) we would like to go virtual with these machines. Outsourcing to the cloud is not an option, not at all, so we'll have to use on-premises hardware and VM hosts. Each Build-Server (master or slave) is a fully configured (installs, licenses, shares in case of the master, ...) Windows Server box. I would now ideally like to just convert the (two) existing physical nodes to VM images and run them. Later add more VM slave instances as clones of the existing ones. And here begin my questions: Should I go for one VM per one hardware-box or should I go for something where a single hardware runs multiple VMs? That would mean a single point of failure hardware wise and doesn't seem like a good idea ... or?? Since we're doing C++ compilation with Visual Studio, I assume that during a build the hardware (processor cores + disk) will be fully utilized, so going with more than one build-node per hardware doesn't seem to make much sense?? Wrt. to hardware options, does it make any difference which VM software we use (VMWare, MS, Virtualbox, ... ?) (We're using Windows exclusively for our builds.) Regarding budget: We have a normal small company (20 developers) budget for this. ;-) That is, if it's going to cost a few k$ it's going to cost. If it's free - the better. I strongly prefer solutions where there's no multi-k$ maintenance costs per year.

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• Excel 2010: dynamic update of drop down list based upon datasource validation worksheet changes

  - by hornetbzz

  I have one worksheet for setting up the data sources of multiple data validation lists. in other words, I'm using this worksheet to provide drop down lists to multiple other worksheets. I need to dynamically update all worksheets upon any of a single or several changes on the data source worksheet. I may understand this should come with event macro over the entire workbook. My question is how to achieve this keeping the "OFFSET" formula across the whole workbook ? Thx To support my question, I put the piece of code that I'm trying to get it working : Provided the following informations : I'm using such a formula for a pseudo dynamic update of the drop down lists, for example : =OFFSET(MyDataSourceSheet!$O$2;0;0;COUNTA(MyDataSourceSheet!O:O)-1) I looked into the pearson book event chapter but I'm too noob for this. I understand this macro and implemented it successfully as a test with the drop down list on the same worksheet as the data source. My point is that I don't know how to deploy this over a complete workbook. Macro related to the datasource worksheet : Option Explicit Private Sub Worksheet_Change(ByVal Target As Range) ' Macro to update all worksheets with drop down list referenced upon ' this data source worksheet, base on ref names Dim cell As Range Dim isect As Range Dim vOldValue As Variant, vNewValue As Variant Dim dvLists(1 To 6) As String 'data validation area Dim OneValidationListName As Variant dvLists(1) = "mylist1" dvLists(2) = "mylist2" dvLists(3) = "mylist3" dvLists(4) = "mylist4" dvLists(5) = "mylist5" dvLists(6) = "mylist6" On Error GoTo errorHandler For Each OneValidationListName In dvLists 'Set isect = Application.Intersect(Target, ThisWorkbook.Names("STEP").RefersToRange) Set isect = Application.Intersect(Target, ThisWorkbook.Names(OneValidationListName).RefersToRange) ' If a change occured in the source data sheet If Not isect Is Nothing Then ' Prevent infinite loops Application.EnableEvents = False ' Get previous value of this cell With Target vNewValue = .Value Application.Undo vOldValue = .Value .Value = vNewValue End With ' LOCAL dropdown lists : For every cell with validation For Each cell In Me.UsedRange.SpecialCells(xlCellTypeAllValidation) With cell ' If it has list validation AND the validation formula matches AND the value is the old value If .Validation.Type = 3 And .Validation.Formula1 = "=" & OneValidationListName And .Value = vOldValue Then ' Debug ' MsgBox "Address: " & Target.Address ' Change the cell value cell.Value = vNewValue End If End With Next cell ' Call to other worksheets update macros Call Sheets(5).UpdateDropDownList(vOldValue, vNewValue) ' GoTo NowGetOut Application.EnableEvents = True End If Next OneValidationListName NowGetOut: Application.EnableEvents = True Exit Sub errorHandler: MsgBox "Err " & Err.Number & " : " & Err.Description Resume NowGetOut End Sub Macro UpdateDropDownList related to the destination worksheet : Sub UpdateDropDownList(Optional vOldValue As Variant, Optional vNewValue As Variant) ' Debug MsgBox "Received info for update : " & vNewValue ' For every cell with validation For Each cell In Me.UsedRange.SpecialCells(xlCellTypeAllValidation) With cell ' If it has list validation AND the validation formula matches AND the value is the old value ' If .Validation.Type = 3 And .Value = vOldValue Then If .Validation.Type = 3 And .Value = vOldValue Then ' Change the cell value cell.Value = vNewValue End If End With Next cell End Sub

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• Initial Review - Mastering Unreal Technology I: Introduction to Level Design with Unreal Engine 3

  - by Matt Christian

  Recently I purchased 3 large volumes on using the Unreal 3 Engine to create levels and custom games.  This past weekend I cracked the spine of the first and started reading.  Here are my early impressions (I'm ~250 pages into it, with appendices it's about 900). Pros Interestingly, the book starts with an overview of the Unreal engines leading up to Unreal 3 (including Gears of War) and follows with some discussion on planning a mod and what goes into the game development process.  This is nice for an intro to the book and is much preferred rather than a simple chapter detailing what is on the included CD, how to install and setup UnrealEd, etc...  While the chapter on Unreal history and planning can be considered 'fluff', it's much less 'fluffy' than most books provide. I need to mention one thing here that is pretty crucial in the way I'm going to continue reviewing this book.  Most technical books like this are used as a shelf reference; as a thick volume you use for looking up techniques every now and again.  Even so, I prefer reading from cover to cover, including chapters I may already be knowledgable on (I'm sure this is typical for most people).  If there was a chapter on installing UnrealEd (the previously mentioned 'fluff'), I would probably force myself to read it, even though I've installed the game and engine multiple times on different systems. Chapter 3 is where we really get to the introduction piece of UnrealEd, creating your first basic level.  This large chapter details creating two small rooms, adding static meshes, adding lighting, creating and adding particle emitters, creating a door that animates with Unreal Matinee and Kismet, static meshes with physics, and other little additions to make your level look less beginner.  This really is a chapter that overviews the entire rest of the book, as each chapter following details the creation and intermediate usages of Static Meshes, Materials, Lighting, etc... One other very nice part to this book is the way the tutorials are setup.  Each tutorial builds off the previous and all are step-by-step.  If you haven't completed one yet, you can find all the starting files on the CD that comes with the book. Cons While the description of the overview chapter (Chapter 3) is fresh in your mind, let me start the cons by saying this chapter is setup extremely confusing for the noob.  At one point, you end up creating a door mesh and setting it up as a InteropMesh so that it is ready to be animated, only to switch to particles and spend a good portion of time working on a different piece of the level.  Yes, this is actually how I develop my levels (jumping back and forth), though it's very odd for a book to jump out of sequence. The next item might be a positive or a negative depending on your skill level with UnrealEd.  Most of the introduction to the editor layout is found in one of the Appendices instead of before Chapter 3.  For new readers, this might lead to confusion as Appendix A would typically be read between Chapter 2 and 3.  However, this is a positive for those with some experience in UnrealEd as they don't have to force themselves through a 'learn every editor button' chapter.  I'm listing this in the Cons section as the book is 'Introduction to...' and is probably going to be directed toward a lot of very beginner developers. Finally, there's a lack of general description to a lot of the underlying engine and what each piece in UnrealEd is or does.  Sometimes you'll be performing Tutorial after Tutorial with barely a paragraph in between describing ANY of what you've just done.  Tutorial 1.1 Step 6 says to press Button X, so you do.  But why?  This is in part a problem with the structure of the tutorials rather than the content of the book.  Since the tutorials are so focused on a step-by-step (or procedural) description of a process, you learn the process and not why you're doing that.  For example, you might learn how to size a material to a surface, but will only learn what buttons to press and not what each one does. This becomes extremely apparent in the chapter on Static Meshes as most of the chapter is spent in 3D Studio Max.  Since there are books on 3DSM and modelling, the book really only tells you the steps and says to go grab a book on modelling if you're really interested in 3DSM.  Again, I've learned the process to develop my own meshes in 3DSM, but I don't know the why behind the steps. Conclusion So far the book is very good though I would have a hard time recommending it to a complete beginner.  I would suggest anyone looking at this book (obviously including the other 2, more advanced volumes) to pick up a copy of UDK or Unreal 3 (available online or via download services such as Steam) and watch some online tutorials and play with it first.  You'll find plenty of online videos available that were created by the authors and may suit as a better introduction to the editor.

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• JavaOne Afterglow by Simon Ritter

  - by JuergenKress

  Last week was the eighteenth JavaOne conference and I thought it would be a good idea to write up my thoughts about how things went. Firstly thanks to Yoshio Terada for the photos, I didn't bother bringing a camera with me so it's good to have some pictures to add to the words. Things kicked off full-throttle on Sunday.  We had the Java Champions and JUG leaders breakfast, which was a great way to meet up with a lot of familiar faces and start talking all things Java.  At midday the show really started with the Strategy and Technical Keynotes.  This was always going to be tougher job than some years because there was no big shiny ball to reveal to the audience.  With the Java EE 7 spec being finalised a few months ago and Java SE 8, Java ME 8 and JDK8 not due until the start of next year there was not going to be any big announcement.  I thought both keynotes worked really well each focusing on the things most important to Java developers: Strategy One of the things that is becoming more and more prominent in many companies marketing is the Internet of Things (IoT).  We've moved from the conventional desktop/laptop environment to much more mobile connected computing with smart phones and tablets.  The next wave of the internet is not just billions of people connected, but 10s or 100s of billions of devices connected to the network, all generating data and providing much more precise control of almost any process you can imagine.  This ties into the ideas of Big Data and Cloud Computing, but implementation is certainly not without its challenges.  As Peter Utzschneider explained it's about three Vs: Volume, Velocity and Value.  All these devices will create huge volumes of data at very high speed; to avoid being overloaded these devices will need some sort of processing capabilities that can filter the useful data from the redundant.  The raw data then needs to be turned into useful information that has value.  To make this happen will require applications on devices, at gateways and on the back-end servers, all very tightly integrated.  This is where Java plays a pivotal role, write once, run everywhere becomes essential, having nine million developers fluent in the language makes it the defacto lingua franca of IoT.  There will be lots more information on how this will become a reality, so watch this space. Technical How do we make the IoT a reality, technically?  Using the game of chess Mark Reinhold, with the help of people like John Ceccarelli, Jasper Potts and Richard Bair, showed what you could do.  Using Java EE on the back end, Java SE and JavaFX on the desktop and Java ME Embedded and JavaFX on devices they showed a complete end-to-end demo. This was really impressive, using 3D features from JavaFX 8 (that's included with JDK8) to make a 3D animated Duke chess board.  Jasper also unveiled the "DukePad" a home made tablet using a Raspberry Pi, touch screen and accelerometer. Although the Raspberry Pi doesn't have earth shattering CPU performance (about the same level as a mid 1990s Pentium), it does have really quite good GPU performance so the GUI works really well.  The plans are all open sourced and available here.  One small, but very significant announcement was that Java SE will now be included with the NOOB and Raspbian Linux distros provided by the Raspberry Pi foundation (these can be found here).  No more hassle having to download and install the JDK after you've flashed your SD card OS image.  The finale was the Raspberry Pi powered chess playing robot.  Really very, very cool.  I talked to Jasper about this and he told me each of the chess pieces had been 3D printed and then he had to use acetone to give them a glossy finish (not sure what his wife thought of him spending hours in the kitchen in a gas mask!)  The way the robot arm worked was very impressive as it did not have any positioning data (like a potentiometer connected to each motor), but relied purely on carefully calibrated timings to get the arm to the right place.  Having done things like this myself in the past I know how easy it is to find a small error gets magnified into very big mistakes. Here's some pictures from the keynote: The "Dukepad" architecture Nice clear perspex case so you can see the innards. The very nice 3D chess set.  Maya's obviously a great tool. Read the full article here. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: Simon Ritter,Java One,OOW,Oracle OpenWorld,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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• libgdx rotation (animation, arrays) issues and help needed

  - by johnny-b

  well i am a noob at java and libgdx. i got the homing bullet working with the help of someone. now i am smashing my head as to how i can make it rotate so it faces the ball (which is the main character) when it goes around it or when it is coming towards it. the bullet is facing <--- and the code below is what i have done so far. also i used sprites for the bullet and also animation method. Also how do i make it an array/arraylist which is best so i can have multiple bullets at random or placed places. i tried many things nothing workd :( thank you for the help. // below is the bullet or enemy if you want to call it. public class Bullet extends Sprite { public static final float BULLET_HOMING = 6000; public static final float BULLET_SPEED = 300; private Vector2 velocity; private float lifetime; public Bullet(float x, float y) { velocity = new Vector2(0, 0); setPosition(x, y); } public void update(float delta) { float targetX = GameWorld.getBall().getX(); float targetY = GameWorld.getBall().getY(); float dx = targetX - getX(); float dy = targetY - getY(); float distToTarget = (float) Math.sqrt(dx * dx + dy * dy); dx /= distToTarget; dy /= distToTarget; dx *= BULLET_HOMING; dy *= BULLET_HOMING; velocity.x += dx * delta; velocity.y += dy * delta; float vMag = (float) Math.sqrt(velocity.x * velocity.x + velocity.y * velocity.y); velocity.x /= vMag; velocity.y /= vMag; velocity.x *= BULLET_SPEED; velocity.y *= BULLET_SPEED; Vector2 v = velocity.cpy().scl(delta); setPosition(getX() + v.x, getY() + v.y); setOriginCenter(); setRotation(velocity.angle()); lifetime += delta; setRegion(AssetLoader.bulletAnimation.getKeyFrame(lifetime)); } } // this is where i load the images. public class AssetLoader { public static Animation bulletAnimation; public static Sprite bullet1, bullet2; public static void load() { texture = new Texture(Gdx.files.internal("SpriteN1.png")); texture.setFilter(TextureFilter.Nearest, TextureFilter.Nearest); bullet1 = new Sprite(texture, 380, 350, 45, 20); bullet1.flip(false, true); bullet2 = new Sprite(texture, 425, 350, 45, 20); bullet2.flip(false, true); Sprite[] bullets = { bullet1, bullet2 }; bulletAnimation = new Animation(0.06f, aims); bulletAnimation.setPlayMode(Animation.PlayMode.LOOP); } public static void dispose() { // We must dispose of the texture when we are finished. texture.dispose(); } // this is for the rendering of the images etc public class GameRenderer { private Bullet bullet; private Ball ball; public GameRenderer(GameWorld world) { myWorld = world; cam = new OrthographicCamera(); cam.setToOrtho(true, 480, 320); batcher = new SpriteBatch(); // Attach batcher to camera batcher.setProjectionMatrix(cam.combined); shapeRenderer = new ShapeRenderer(); shapeRenderer.setProjectionMatrix(cam.combined); // Call helper methods to initialize instance variables initGameObjects(); initAssets(); } private void initGameObjects() { ball = GameWorld.getBall(); bullet = myWorld.getBullet(); scroller = myWorld.getScroller(); } private void initAssets() { ballAnimation = AssetLoader.ballAnimation; bulletAnimation = AssetLoader.bulletAnimation; } public void render(float runTime) { Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT); batcher.begin(); // Disable transparency // This is good for performance when drawing images that do not require // transparency. batcher.disableBlending(); // The ball needs transparency, so we enable that again. batcher.enableBlending(); batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight()); batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY()); // End SpriteBatch batcher.end(); } } // this is to load the image etc on the screen i guess public class GameWorld { public static Ball ball; private Bullet bullet; private ScrollHandler scroller; public GameWorld() { ball = new Ball(480, 273, 32, 32); bullet = new Bullet(10, 10); scroller = new ScrollHandler(0); } public void update(float delta) { ball.update(delta); bullet.update(delta); scroller.update(delta); } public static Ball getBall() { return ball; } public ScrollHandler getScroller() { return scroller; } public Bullet getBullet() { return bullet; } } so there is the whole thing. the images are loaded via the AssetLoader then to the GameRenderer and GameWorld via the Bullet class. i am guessing that is how it is. sorry newbie so still learning. thank you in advace for the help or any advice.

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• OpenGL 3 and the Radeon HD 4850x2

  - by rotard

  A while ago, I picked up a copy of the OpenGL SuperBible fifth edition and slowly and painfully started teaching myself OpenGL the 3.3 way, after having been used to the 1.0 way from school way back when. Making things more challenging, I am primarily a .NET developer, so I was working in Mono with the OpenTK OpenGL wrapper. On my laptop, I put together a program that let the user walk around a simple landscape using a couple shaders that implemented per-vertex coloring and lighting and texture mapping. Everything was working brilliantly until I ran the same program on my desktop. Disaster! Nothing would render! I have chopped my program down to the point where the camera sits near the origin, pointing at the origin, and renders a square (technically, a triangle fan). The quad renders perfectly on my laptop, coloring, lighting, texturing and all, but the desktop renders a small distorted non-square quadrilateral that is colored incorrectly, not affected by the lights, and not textured. I suspect the graphics card is at fault, because I get the same result whether I am booted into Ubuntu 10.10 or Win XP. I did find that if I pare the vertex shader down to ONLY outputting the positional data and the fragment shader to ONLY outputting a solid color (white) the quad renders correctly. But as SOON as I start passing in color data (whether or not I use it in the fragment shader) the output from the vertex shader is distorted again. The shaders follow. I left the pre-existing code in, but commented out so you can get an idea what I was trying to do. I'm a noob at glsl so the code could probably be a lot better. My laptop is an old lenovo T61p with a Centrino (Core 2) Duo and an nVidia Quadro graphics card running Ubuntu 10.10 My desktop has an i7 with a Radeon HD 4850 x2 (single card, dual GPU) from Saphire dual booting into Ubuntu 10.10 and Windows XP. The problem occurs in both XP and Ubuntu. Can anyone see something wrong that I am missing? What is "special" about my HD 4850x2? string vertexShaderSource = @" #version 330 precision highp float; uniform mat4 projection_matrix; uniform mat4 modelview_matrix; //uniform mat4 normal_matrix; //uniform mat4 cmv_matrix; //Camera modelview. Light sources are transformed by this matrix. //uniform vec3 ambient_color; //uniform vec3 diffuse_color; //uniform vec3 diffuse_direction; in vec4 in_position; in vec4 in_color; //in vec3 in_normal; //in vec3 in_tex_coords; out vec4 varyingColor; //out vec3 varyingTexCoords; void main(void) { //Get surface normal in eye coordinates //vec4 vEyeNormal = normal_matrix * vec4(in_normal, 0); //Get vertex position in eye coordinates //vec4 vPosition4 = modelview_matrix * vec4(in_position, 0); //vec3 vPosition3 = vPosition4.xyz / vPosition4.w; //Get vector to light source in eye coordinates //vec3 lightVecNormalized = normalize(diffuse_direction); //vec3 vLightDir = normalize((cmv_matrix * vec4(lightVecNormalized, 0)).xyz); //Dot product gives us diffuse intensity //float diff = max(0.0, dot(vEyeNormal.xyz, vLightDir.xyz)); //Multiply intensity by diffuse color, force alpha to 1.0 //varyingColor.xyz = in_color * diff * diffuse_color.xyz; varyingColor = in_color; //varyingTexCoords = in_tex_coords; gl_Position = projection_matrix * modelview_matrix * in_position; }"; string fragmentShaderSource = @" #version 330 //#extension GL_EXT_gpu_shader4 : enable precision highp float; //uniform sampler2DArray colorMap; //in vec4 varyingColor; //in vec3 varyingTexCoords; out vec4 out_frag_color; void main(void) { out_frag_color = vec4(1,1,1,1); //out_frag_color = varyingColor; //out_frag_color = vec4(varyingColor, 1) * texture(colorMap, varyingTexCoords.st); //out_frag_color = vec4(varyingColor, 1) * texture(colorMap, vec3(varyingTexCoords.st, 0)); //out_frag_color = vec4(varyingColor, 1) * texture2DArray(colorMap, varyingTexCoords); }"; Note that in this code the color data is accepted but not actually used. The geometry is outputted the same (wrong) whether the fragment shader uses varyingColor or not. Only if I comment out the line varyingColor = in_color; does the geometry output correctly. Originally the shaders took in vec3 inputs, I only modified them to take vec4s while troubleshooting.

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• Increasing efficiency of N-Body gravity simulation

  - by Postman

  I'm making a space exploration type game, it will have many planets and other objects that will all have realistic gravity. I currently have a system in place that works, but if the number of planets goes above 70, the FPS decreases an practically exponential rates. I'm making it in C# and XNA. My guess is that I should be able to do gravity calculations between 100 objects without this kind of strain, so clearly my method is not as efficient as it should be. I have two files, Gravity.cs and EntityEngine.cs. Gravity manages JUST the gravity calculations, EntityEngine creates an instance of Gravity and runs it, along with other entity related methods. EntityEngine.cs public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { e.Value.Update(); } gravity.Update(); } (Only relevant piece of code from EntityEngine, self explanatory. When an instance of Gravity is made in entityEngine, it passes itself (this) into it, so that gravity can have access to entityEngine.Entities (a dictionary of all planet objects)) Gravity.cs namespace ExplorationEngine { public class Gravity { private EntityEngine entityEngine; private Vector2 Force; private Vector2 VecForce; private float distance; private float mult; public Gravity(EntityEngine e) { entityEngine = e; } public void Update() { //First loop foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { //Reset the force vector Force = new Vector2(); //Second loop foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { //Make sure the second value is not the current value from the first loop if (e2.Value != e.Value ) { //Find the distance between the two objects. Because Fg = G * ((M1 * M2) / r^2), using Vector2.Distance() and then squaring it //is pointless and inefficient because distance uses a sqrt, squaring the result simple cancels that sqrt. distance = Vector2.DistanceSquared(e2.Value.Position, e.Value.Position); //This makes sure that two planets do not attract eachother if they are touching, completely unnecessary when I add collision, //For now it just makes it so that the planets are not glitchy, performance is not significantly improved by removing this IF if (Math.Sqrt(distance) > (e.Value.Texture.Width / 2 + e2.Value.Texture.Width / 2)) { //Calculate the magnitude of Fg (I'm using my own gravitational constant (G) for the sake of time (I know it's 1 at the moment, but I've been changing it) mult = 1.0f * ((e.Value.Mass * e2.Value.Mass) / distance); //Calculate the direction of the force, simply subtracting the positions and normalizing works, this fixes diagonal vectors //from having a larger value, and basically makes VecForce a direction. VecForce = e2.Value.Position - e.Value.Position; VecForce.Normalize(); //Add the vector for each planet in the second loop to a force var. Force = Vector2.Add(Force, VecForce * mult); //I have tried Force += VecForce * mult, and have not noticed much of an increase in speed. } } } //Add that force to the first loop's planet's position (later on I'll instead add to acceleration, to account for inertia) e.Value.Position += Force; } } } } I have used various tips (about gravity optimizing, not threading) from THIS question (that I made yesterday). I've made this gravity method (Gravity.Update) as efficient as I know how to make it. This O(N^2) algorithm still seems to be eating up all of my CPU power though. Here is a LINK (google drive, go to File download, keep .Exe with the content folder, you will need XNA Framework 4.0 Redist. if you don't already have it) to the current version of my game. Left click makes a planet, right click removes the last planet. Mouse moves the camera, scroll wheel zooms in and out. Watch the FPS and Planet Count to see what I mean about performance issues past 70 planets. (ALL 70 planets must be moving, I've had 100 stationary planets and only 5 or so moving ones while still having 300 fps, the issue arises when 70+ are moving around) After 70 planets are made, performance tanks exponentially. With < 70 planets, I get 330 fps (I have it capped at 300). At 90 planets, the FPS is about 2, more than that and it sticks around at 0 FPS. Strangely enough, when all planets are stationary, the FPS climbs back up to around 300, but as soon as something moves, it goes right back down to what it was, I have no systems in place to make this happen, it just does. I considered multithreading, but that previous question I asked taught me a thing or two, and I see now that that's not a viable option. I've also thought maybe I could do the calculations on my GPU instead, though I don't think it should be necessary. I also do not know how to do this, it is not a simple concept and I want to avoid it unless someone knows a really noob friendly simple way to do it that will work for an n-body gravity calculation. (I have an NVidia gtx 660) Lastly I've considered using a quadtree type system. (Barnes Hut simulation) I've been told (in the previous question) that this is a good method that is commonly used, and it seems logical and straightforward, however the implementation is way over my head and I haven't found a good tutorial for C# yet that explains it in a way I can understand, or uses code I can eventually figure out. So my question is this: How can I make my gravity method more efficient, allowing me to use more than 100 objects (I can render 1000 planets with constant 300+ FPS without gravity calculations), and if I can't do much to improve performance (including some kind of quadtree system), could I use my GPU to do the calculations?

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• OS choice between: Debian, gNewSense, and OpenSolaris

  - by penyuan

  I am planning to migrate from Mac OS X and Windows to either a Unix or Linux distribution, i.e. I am a Linux/Unix beginner. Right now the following caught my interest: Debian: Well established with huge repository of 20000+ apps. gNewSence: "Totally free" version of Ubuntu, so it should be more beginner friendly? OpenSolaris: Also open-source, and built on "strong" Unix base. I do mainly basic tasks such as web browsing, office work, maintaining big photo collection, and a little bit of programming. Questions: How "free" are each of these distributions compared to each other, is this whole freedom thing a big deal? Will a binary labeled as for Ubuntu work on gNewSense? What are simple IDEs for Debian and gNewSense?

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• rename file names from lower case to upper case

  - by Adnan

  Hello, I have about 2k of file that are currently in lower case like: file_one.cfr file_two.cfr .... I am searching for a fast way to rename them to upper case so they would be like; FILE_ONE.cfr FILE_TWO.cfr .... If I use from my shell; for i in *; do mv $i `echo $i | tr [:lower:] [:upper:]`; done I can get all file and the file extensions to upper case. But the extension should remain in lowercase, so my approach does not work. Any programming language is welcome.

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• Windows 7 Software Installation : Siemens Step7 and Siemens SCL

  - by Shaharyar

  Hello sysadmins, We use Siemens Step7 and SCL for PLC programming in our company. I recently got to install Windows 7 and had yet to find out that the Siemens software suite doesn't install anymore. - Which is a pain... Checking through the setup files, I found following entries in the Setups.ini file: [OS] PlattformIDAllowed=1;2 WinXP=True WinXPExclude=0,Home,1 WinXPWarning=1 WinNETServer=True WinNETServerExclude=Home,0,1 WinNETServerWarning=Home,0,1 Win2003=1 Win2003Exclude=Home,0,1 Win2003Warning=Home,0,1 Win2003R2=1 Win2003R2Exclude=0,1 Win2003R2Warning=0,1 WinVista=1 Win2008=1 Win7=1 I added the last line to try things out and it still provides me the same error.. As far as I know the suite is installed by Install**Shield**. All help would be very appreciated!

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• Using a secondary DNS when lookup fails in primary? [migrated]

  - by Huckle

  I use a VPN to connect my development machine to my school's CS dept. The development machine is Ubuntu as we do C programming in Unix. I used vpnc to do that. The school uses some DNS entries that only resolve on their DNS servers, i.e., internalserver.csdept.school.edu I am normally attached to the VPN whenever booted for convenience. However I noticed the other day that when I disconnect the VPN all my DNS queries fail. This obviously means that vpnc set up the school's DNS to be used. However I'd rather not use their DNS all the time (tracking and privacy and whatnot). Is there a way I can restore my ISP's DNS and then if the lookup fails, have it use my school's DNS?

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• Eclipse making background video skip with almost every click of the mouse

  - by RustyH

  The problem is i like to listen to videos online (mostly or all flash video) while programming and never had any problems until i started using eclipse, now every time i do just about anything other than type, it makes the video skip/freeze really bad and is really annoying. I have never had this happen using visual studio, netbeans, or adobe flash for that matter, unless i was compiling or doing something that hogs the processor. Are there any settings that might could fix this its getting really annoying. it happens almost every time i even click "find" on the find pop-up window and it is not like it is having to search a big file or anything it is only 700 lines, with honestly only about 1/2 that have content on them. Any ideas?

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• Safari corrupting downloads?

  - by Kaji

  First off, a bit of background: I had to do an erase and install about 2-3 weeks ago, so this is a fresh, up-to-date installation of Snow Leopard we're dealing with. That said, I decided recently to branch out from simply programming PHP in a text editor and explore some of the other technologies I keep hearing about, and picked up Drupal, Joomla, and the Zend Framework from their respective official sites. Latest complete, stable builds for all 3. Drupal and Joomla downloaded without a problem, but when I put them in my /~username/Sites folder, XAMPP pretends they're not there, even if I restart Apache or the laptop itself. Zend's archive won't open at all. Is Safari corrupting the downloads, or are there other issues in play that can be investigated?

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• Vertical alignment problem in textbox in MS Word 2007

  - by Surjya Narayana Padhi

  Hi, I pardon as its not a programming question at all. But if anybody can answer this it will be usefull for me. In MS word 2007 I drew a textbox and entered some text. Then I right clicked on textbox and went to format shape Then went to TextBox tab and reduced the top internal margin to 0.1 cm. But still it seems there is too much space at the top inside the textbox. I am not able to position the text exactly at the vertical middle of textbox. If I choose the auto-rezide option in format Shape, the textBox size is increases automatically but the text remains exactly at vertical and horizontal middle of textbox. but anyhow I need the textbox to be small. This is very minor but annoying problem. Can anybody help?

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