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• DNS protocol message example

  - by virtual-lab

  hello there, I am trying to figure out how to send out DNS messages from an application socket adapter to a DNSBL. I spent the last two days understanding the basics, including experimenting with WireShark to catch an example of message exchanged. Now I would like to query the DNS without using dig or host command (I'm using Ubuntu); how can I perform this action at low level, without the help of these tools in wrapping the request in a proper DNS message format? How the message should be post it? Hex or String? Thanks in advance for any help. Regards Alessandro Ilardo Comment added I am investigating on JDev and Oracle SOA. The platform provides a Socket Adapter which simply apply a transformation (XSLT) and send the message straight to the socket. How the payload parameters (ex. the host I'm looking up) are wrapped within the message is left to the developer. So basically I have an idea on how the all DNS message is structured, but rather than put everything on JDev stright away I'd like to make some tests on my own just to make sure I got a valid message format. So, I am not using any specific language (I don't even understand why they moved my question from serverfault) and I don't want to use any tools which would hide part of the message, such as the header. I know they work well btw. I guess this stuff has something to do with packet injection. Someone suggested me to use telnet, but I've only used for SMTP or HTTP, I haven't got a clue on how it works for DNS request. Does it make more sense now?

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• iPhone development - app design patterns

  - by occulus

  There are tons of resources concerning coding on the iPhone. Most of them concern "how do I do X", e.g. "setup a navigation controller", or "download text from a URL". All good and fine. What I'm more interested in now are the questions that follow the simpler stuff - how to best structure your complex UI, or your app, or the common problems that arise. To illustrate: a book like "Beginning iPhone 3 Development" tells you how to set up a multi viewcontroller app with an top 'switcher' viewcontroller that switches between views owned by other view controllers. Fine, but you're only told how to do that, and nothing about the problems that can follow: for example, if I use their paradigm to switch to a UINavigationViewController, the Navigation bar ends up too low on the screen, because UINavigationViewController expects to be the topmost UIViewController (apparently). Also, delegate methods (e.g. relating to orientation changes) go to the top switcher view controller, not the actual controller responsible for the current view. I have fixes for these things but they feel like hacks which makes me unhappy and makes me feel like I'm missing something. One productive thing might be to look at some open source iPhone projects (see this question). But aside from that?

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• Publishing WCF .NET 3.5 to IIS 5.1

  - by Adam

  I've been developing a WCF web service using .NET 3.5 with IIS7 and it works perfectly on my local computer. I tried publishing it to a server running IIS 5.1 and even though I can view the WSDL in my browser, the client application doesn't seem to be connecting to it correctly. I launched a packet sniffing app (Charles Proxy) and the response for the first message comes back to the client empty (0 bytes). Every message after the first one times out. The WCF service is part of a larger application that uses ASP .NET 3.5. That application has been working fine on IIS 5.1 for awhile now so I think it's something specific to WCF. I also tried throwing an exception in the SVC file to see if it made it that far and the exception never got thrown so I have a feeling it's something more low level that's not working. Any thoughts? Is there anything I need to install on the IIS5 server? If so how am I still able to view the WSDL in my browser?

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• On the search for my next great .Net Read

  - by user127954

  Just got done with "The art of unit testing". It was a great read and i think everyone should go buy a copy. With that said i think the next book I'm like to read would be a architecture / Design type book that would focus heavily on building your objects / software in such a way that it would be: Low Coupling High Cohesion Easily Maintainable / Extended Easy to test Easy to Navigate / Debug The above characteristcs are the most important ones but also maybe it would also include (but not necessary) designing for: Performance - Don't want to design a system at at the end find out its dog slow :) Scalability - Again don't want to design something at the end find out it won't scale. I'd also prefer (but not necessary again): Something newer - Architectural principles seem to gradually evolve / improve over time and id like something with current thinking. .Net as illustrating language - like i said above its not mandatory but since its what i use every day id prefer it to be in .net. Doesn't really matter if its in vb.net or c# Some of the topics that would be talked about its how to minimize dependencies and using interfaces throughout your solution rather than concrete classes. Maybe it would constract /compare some of the newest design principles like DDD, Repository Pattern, Ect... I already have "Clean Code" (don't know if its this type of book or not) and "Working effectively with legacy code" on my radar but id like to read a book based upon the topic i talked about above first. Is there such a book?

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• How can I use a meter-style progress bar?

  - by Yadyn

  In Vista/7, the Windows Explorer shell window makes use of a special kind of static progress bar to display hard drive space. With default styles, this bar is blue colored and non-animated. It also turns red colored when it gets close to being full (low disk space). Using messaging, I can tell the Windows Forms ProgressBar control to update its state to Paused and Error (yellow and red colored, respectively), which works fine, but these are still specific to progress. In the Windows User Experience Guidelines, it specifically points out this "meter" variant of the Progress Bar: This pattern isn't a progress bar, but it is implemented using the progress bar control. Meters have a distinct look to differentiate them from true progress bars. They say it "is implemented using the progress bar control", so... how? What message could I send to the control to have it behave this way? I've seen that you can send messages for setting the bar color, but the documentation says these calls are ignored when visual styles are enabled. Nothing else in the Windows API documentation for raw ProgressBar controls seemed to suggest a way to do this. Am I just stuck making a custom drawn bar? I'd really like to utilize the OS whenever possible so that the application will appear consistent throughout different OS versions. I realize that pre-Vista versions probably won't support this, though. I'm looking for a Windows Forms solution, but I wonder if it is even exposed at all via Win32 API.

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• Using CGContextDrawTiledImage at different zooms causes massive memory growth

  - by Jacques

  I'm working on app an where there's a view in a zoomable UIScrollView. When the user zooms in or out, I redraw the view that's in the UIScrollView to be nice and sharp. That view has a background image that I draw with CGContextDrawTiledImage. I noticed that memory usage grows every time I switch to a new zoom level. It looks like CGContextDrawTiledImage keeps a cache somewhere of the image scaled to different sizes. So, If I go from 1.0 to 1.1x zoom, memory use grows. Going back to 1.0 doesn't cause it to grow, but then going to 1.05 and then 1.2 causes it to grow twice. Back to 1.1 and no growth. Of course, the zoom level is under user control so I don't have control over how many zoom levels happen. Right now my background image is kind of massive (512x512), so this causes memory usage to grow very quickly. It doesn't show up as a memory leak in Instruments, just additional allocations that never get freed. I've tried to find a way to free the cache that appears to be being created, but no luck. It doesn't seem to respond to low memory warnings, for example. I also tried setting the view's backgroundColor to a UIColor created with colorWithPatternImage, but that doesn't work because I'm doing the scaling by changing the graphics context's CTM, not by setting the view's transform. Any ideas on how to keep memory usage from blowing up?

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• Get Highest Res Favicon

  - by Jeremy

  I'm making a website that needs to dynamically obtain the favicon of sites upon request. I've found a few api's that can accomplish this fairly well, and so far I'm liking http://www.fvicon.com/. The final image for my website will be 64x64px, and some websites such as Google and Wordpress have nice images of this size that are easily retrieved via this api. Though, of course, most websites only have a 16x16 favicon image and scaling that image to 64x64 has very bad quality loss. Examples: (high res) http://a.fvicon.com/wordpress.com?format=png&width=64&height=64 (low res) http://a.fvicon.com/yahoo.com?format=png&width=64&height=64 Keeping this in mind, I'm planning on somehow determining whether a high-res image is available and, if so, the website will use this image. If not, I want to use a pre-made 64x64 icon with the smaller icon layered over it. What I'm having trouble with is determining if there is a high res favicon available or not. Also, I'm curious if there's a better approach to this situation. I'd rather not use smaller images (64x64 works out really well for this project). The lowest res I'm willing to drop to is 48x48 but even then there will be a significant quality loss for scaling up 16x16 favicons. Any ideas? If you need any more information I will gladly provide it. Thank you!

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• getting another website data to manipulate it's value in perl

  - by aun ali

  use CGI qw(:standard); use CGI::Carp qw(fatalsToBrowser warningsToBrowser); our @a=param(src="http://fxrates.forexpros.com/index.php?pairs_ids=1525=last_update"); print header(),start_html('results.pl'); $a=http://fxrates.forexpros.com/index.php?pairs_ids=1525=last_update; '<iframe frameborder="0" scrolling="no" height="95" width="213" allowtransparency="true" marginwidth="0" marginheight="0" src="http://fxrates.forexpros.com/index.php?pairs_ids=1525;&header-text-color=%23FFFFFF&curr-name-color=%230059b0&inner-text-color=%23000000&green-text-color=%232A8215&green-background=%23B7F4C2&red-text-color=%23DC0001&red-background=%23FFE2E2&inner-border-color=%23CBCBCB&border-color=%23cbcbcb&bg1=%23F6F6F6&bg2=%23ffffff&bid=hide&ask=hide&last=hide&high=hide&low=hide&change=hide&change_in_percents=hide&last_update=show"></iframe><br /><div style="width:213"><span style="float:left"><span style="font-size: 11px;color: #333333;text-decoration: none;">The <a href="http://www.forexpros.com/quotes" target="_blank" style="font-size: 11px;color: #06529D; font-weight: bold;" class="underline_link">Forex Quotes</a> are Powered by Forexpros - The Leading Financial Portal.</span></span></div>'; print '<br/>'; print "$a"; print end_html();' getting error: Can't modify constant item in scalar assignment at livedata.pl line 4, near ""http://fxrates.forexpros.com/index.php?pairs_ids=1525=last_update")" syntax error at livedata.pl line 6, near "http:" Execution of livedata.pl aborted due to compilation errors.

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• MySQL to SQL Server ODBC Connector?

  - by Scott C.

  My boss wants to have data in MySQL DBs used for our website to be "linked and synced" with a Financial Server that has its DB in SQL Server. Sooooo...even though I have no idea how to accomplish this, this just sounds like an absolute nightmare especially since the MySQL DB is most likely going to be hosted in the cloud and not on a machine next to the Financial Server. Any ideas how to accomplish this? (within reason?) Also, his big thing is he wants to basically pull up the data from any record a user enters and using data pulled from that do all sorts of calculations using ANOTHER program that stores its data (apparently) in SQL Server. Thinking of all the data I might have to convert makes me very uneasy. Please tell a ODBC eliminates complicated junk like this. :/ I'm trying to talk him into just having MySQL do a nightly dump into a CSV file or something and using that (rather than connector) to update the SQL Server DBs. I guess I'm just not that comfortable with a server and/or programming I have no say over being connected DIRECTLY to my MySQL DB for the website. If there's no good answer for this, can anyone offer a suggestion as to what I can say to talk him out of this? (I'm a low-level IT guy w/ a decent grasp on programming...but I'm no expert - should I try to push this off to a seasoned IT pro?) Thanks in advance.

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• Building a survey to put in a WordPress website using Python/Django

  - by chiurox

  So I've been given a task to build a survey to get data regarding time slot preferences of prospective students for a particular course. I know there are really quick solutions to this like Google Forms, SurveyMonkey, but since it's not unusually hard, I want to implement the survey myself in a totally new language as an opportunity to get started with it and also be able to customize and provide dynamic info to the users who are voting. Although I have done some stuff in PHP, C++, javascript, etc, I'm pretty new to Python+Django framework but it's something I've been meaning to get into since a long time ago. Initially, what I want is to make a grid with the days of the week as columns and time-durations as rows. In each cell I want to provide users a way to choose how strong (high/medium/low) their preference for this particular day+time is. I also want to show how many "votes" have already been cast for this particular preference because this will influence a lot in their decisions and as a result make this process easier when we are going to define the classes. I'll probably store the data in MySQL. Could anyone point me to some really good Python+Django tutorials for my particular purpose? Does anyone think I'm wasting my time with this trivial task by choosing new tools and that I should just use something I already know (like PHP) or a free service or plugin for Wordpress? Thanks!

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• How to collect and inject all beans of a given type in Spring XML configuration

  - by GrzegorzOledzki

  One of the strongest accents of the Spring framework is the Dependency Injection concept. I understand one of the advices behind that is to separate general high-level mechanism from low-level details (as announced by Dependency Inversion Principle). Technically, that boils down to having a bean implementation to know as little as possible about a bean being injected as a dependency, e.g. public class PrintOutBean { private LogicBean logicBean; public void action() { System.out.println(logicBean.humanReadableDetails()); } //... } <bean class="PrintOutBean"> <property name="loginBean" ref="ShoppingCartBean"/> </bean> But what if I wanted to a have a high-level mechanism operating on multiple dependent beans? public class MenuManagementBean { private Collection<Option> options; public void printOut() { for (Option option:options) { // do something for option } //... } } I know one solution would be to use @Autowired annotation in the singleton bean, that is... @Autowired private Collection<Option> options; But doesn't it violate the separation principle? Why do I have to specify what dependents to take in the very same place I use them (i.e. MenuManagementBean class in my example)? Is there a way to inject collections of beans in the XML configuration like this (without any annotation in the MMB class)? <bean class="MenuManagementBean"> <property name="options"> <xxx:autowire by-type="MyOptionImpl"/> </property> </bean>

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• Connection Pool Strategy: Good, Bad or Ugly?

  - by Drew

  I'm in charge of developing and maintaining a group of Web Applications that are centered around similar data. The architecture I decided on at the time was that each application would have their own database and web-root application. Each application maintains a connection pool to its own database and a central database for shared data (logins, etc.) A co-worker has been positing that this strategy will not scale because having so many different connection pools will not be scalable and that we should refactor the database so that all of the different applications use a single central database and that any modifications that may be unique to a system will need to be reflected from that one database and then use a single pool powered by Tomcat. He has posited that there is a lot of "meta data" that goes back and forth across the network to maintain a connection pool. My understanding is that with proper tuning to use only as many connections as necessary across the different pools (low volume apps getting less connections, high volume apps getting more, etc.) that the number of pools doesn't matter compared to the number of connections or more formally that the difference in overhead required to maintain 3 pools of 10 connections is negligible compared to 1 pool of 30 connections. The reasoning behind initially breaking the systems into a one-app-one-database design was that there are likely going to be differences between the apps and that each system could make modifications on the schema as needed. Similarly, it eliminated the possibility of system data bleeding through to other apps. Unfortunately there is not strong leadership in the company to make a hard decision. Although my co-worker is backing up his worries only with vagueness, I want to make sure I understand the ramifications of multiple small databases/connections versus one large database/connection pool.

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• File upload fails when user is authenticated. Using IIS7 Integrated mode.

  - by Nikkelmann

  These are the user identities my website tells me that it uses: Logged on: NT AUTHORITY\NETWORK SERVICE (Can not write any files at all) and Not logged on: WSW32\IUSR_77 (Can write files to any folder) I have a ASP.NET 4.0 website on a shared hosting IIS7 web server running in Integrated mode with 32-bit applications support enabled and MSSQL 2008. Using classic mode is not an option since I need to secure some static files and I use Routing. In my web.config file I have set the following: <system.webServer> <modules runAllManagedModulesForAllRequests="true" /> </system.webServer> My hosting company says that Impersonation is enabled by default on machine level, so this is not something I can change. I asked their support and they referred me to this article: http://www.codinghub.net/2010/08/differences-between-integrated-mode-and.html Citing this part: Different windows identity in Forms authentication When Forms Authentication is used by an application and anonymous access is allowed, the Integrated mode identity differs from the Classic mode identity in the following ways: * ServerVariables["LOGON_USER"] is filled. * Request.LogognUserIdentity uses the credentials of the [NT AUTHORITY\NETWORK SERVICE] account instead of the [NT AUTHORITY\INTERNET USER] account. This behavior occurs because authentication is performed in a single stage in Integrated mode. Conversely, in Classic mode, authentication occurs first with IIS 7.0 using anonymous access, and then with ASP.NET using Forms authentication. Thus, the result of the authentication is always a single user-- the Forms authentication user. AUTH_USER/LOGON_USER returns this same user because the Forms authentication user credentials are synchronized between IIS 7.0 and ASP.NET. A side effect is that LOGON_USER, HttpRequest.LogonUserIdentity, and impersonation no longer can access the Anonymous user credentials that IIS 7.0 would have authenticated by using Classic mode. How do I set up my website so that it can use the proper identity with the proper permissions? I've looked high and low for any answers regarding this specific problem, but found nil so far... I hope you can help!

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• Specific Shopping Cart Recommendations

  - by Dean J

  I'm trying to suggest a solution for a friend who owns an existing web shop. The current solution isn't cutting it. The new solution needs to have a few things that look like they're enterprise-only if I go with Magento, and $12k a year for a store with maybe $20k in stock just doesn't work. The site should have items, which have one or more categories. Each category may have a parent category. Items have MSRP, and a discount rate by supplier, brand, and sometimes additional discount by product. When a user buys something, it should automatically setup a shipping label with UPS or USPS, depending on user's choice, and build two invoices; one to go in the box, one to go into records. This is crucial; it's low profit per item, so it needs to minimize labor here. Need to be able to have sales (limited by time), discount codes/coupon codes. Ideally would have private sales and/or members-only rates as well. It needs a payment gateway; Paypal/GCheckout-only isn't going to fly. Must be able to accept Visa/MC. Suggestions? I'm debating just building this myself in Java or PHP, but wanted to point my friend to a reasonable-cost solution that already exists if I can. This all seems pretty straightforward to code, save working with the UPS/USPS/Visa/MC APIs, and doing CSS for it.

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• [LaTeX] positions of page numbers, position of chapter headings, chapters AND Table of Contents, Ref

  - by kaikanmonaco

  I am writing my PhD thesis (120+ pages) in latex, the deadline is approaching and I am struggling with layout problems. I am using the documentstyle book. I am posting both problems in this one thread because I am not sure if the solution might be related to both problems or not. Problems are: 1.) The page numbers are mostly located on the top-right of each page (this is correct and where I want them to be). However, only on the first page of chapters and on the first page of what I call "special chapters", the page number is located bottom-centered. With "special chapters" I mean: List of Contents, List of Figures, List of Tables, References, Index. My university will not accept the thesis like this. The page number must ALWAYS be top-right one each page, even if the page is the first page of a chapter or the first page of something like the List of Contents. How can I fix this? 2.) On the first page of chapters and "special chapters" (List of Contents...), the chapter title is located far too low on the page. This is the standard layout of LaTeX with documentstyle book I think. However, the chapter title must start at the very top of the page! I.e. the same height as the normal text on the pages that follow. I mean the chapter title, not the header. I.e., if there is a chapter called "Chapter 1 Dynamics of foobar under mechanical stress" then that text has to start from the top the page, but right now it starts several centimeters below the top. How can I fix this? Have tried all kinds of things to no effect, I'd be very thankful for a solution! Thanks.

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• Best (Java) book for understanding 'under the bonnet' for programming?

  - by Ben

  What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

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• Creating a network adapter - how hard is it?

  - by Vilx-

  I'm interested in building a little (commercial) device on top of Arduino. I want it to be able to interface with network. Network as in standard Ethernet, Cat5, RJ-45, etc. I know that there is an Ethernet Shield, but it costs even more than the Arduino itself, and it's pretty big. Naturally, I want my device to be as small and as cheap as possible. So I'm thinking about recreating an Ethernet module myself. The problem is - I haven't got any experience with Ethernet, nor do I have a good idea where to start looking. Thus I can't even say if my ideas are feasible. Ultimately I would like the device to have three ports - one for incoming signal, two for outgoing, so the device is essentially a little switch where it is plugged in itself as well. The switching capabilities need not be very fast - the volume of data will be low. 10Mbit is more than enough, can be even slower. If that is not possible, a single port for controlling the device itself will also do. Another possibility I'm considering is power line communications - sending information through power lines. That's another area I've no experience with. What hardware should I be looking at, and where can I find information about the necessary software? So - can anyone tell me if these ideas are feasible, and if yes - where should I start looking?

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• Deterministic floating point and .NET

  - by code2code

  How can I guarantee that floating point calculations in a .NET application (say in C#) always produce the same bit-exact result? Especially when using different versions of .NET and running on different platforms (x86 vs x86_64). Inaccuracies of floating point operations do not matter. In Java I'd use strictfp. In C/C++ and other low level languages this problem is essentially solved by accessing the FPU / SSE control registers but that's probably not possible in .NET. Even with control of the FPU control register the JIT of .NET will generate different code on different platforms. Something like HotSpot would be even worse in this case... Why do I need it? I'm thinking about writing a real-time strategy (RTS) game which heavily depends on fast floating point math together with a lock stepped simulation. Essentially I will only transmit user input across the network. This also applies to other games which implement replays by storing the user input. Not an option are: decimals (too slow) fixed point values (too slow and cumbersome when using sqrt, sin, cos, tan, atan...) update state across the network like an FPS: Sending position information for hundreds or a few thousand units is not an option Any ideas?

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• How string accepting interface should look like?

  - by ybungalobill

  Hello, This is a follow up of this question. Suppose I write a C++ interface that accepts or returns a const string. I can use a const char* zero-terminated string: void f(const char* str); // (1) The other way would be to use an std::string: void f(const string& str); // (2) It's also possible to write an overload and accept both: void f(const char* str); // (3) void f(const string& str); Or even a template in conjunction with boost string algorithms: template<class Range> void f(const Range& str); // (4) My thoughts are: (1) is not C++ish and may be less efficient when subsequent operations may need to know the string length. (2) is bad because now f("long very long C string"); invokes a construction of std::string which involves a heap allocation. If f uses that string just to pass it to some low-level interface that expects a C-string (like fopen) then it is just a waste of resources. (3) causes code duplication. Although one f can call the other depending on what is the most efficient implementation. However we can't overload based on return type, like in case of std::exception::what() that returns a const char*. (4) doesn't work with separate compilation and may cause even larger code bloat. Choosing between (1) and (2) based on what's needed by the implementation is, well, leaking an implementation detail to the interface. The question is: what is the preffered way? Is there any single guideline I can follow? What's your experience?

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• Continuous build infrastructure recommendations for primarily C++; GreenHills Integrity

  - by andersoj

  I need your recommendations for continuous build products for a large (1-2MLOC) software development project. Characteristics: ClearCase revision control Approx 80% C++; 15% Java; 5% script or low-level Compiles for Green Hills Integrity OS, but also some windows and JVM chunks Mostly an embedded system; also includes some UI pieces and some development support (simulation tools, config tools, etc...) Each notional "version" of the deliverable includes deployment images for a number of boards, UI machines, etc... (~10 separate images; 5 distinct operating systems) Need to maintain/track many simultaneous versions which, notably, are built for a variety of different board support packages Build cycle time is a major issue on the project, need support for whatever features help address this (mostly need to manage a large farm of build machines, I guess..) Operates in a secure environment (this is a gov't program) (Edited to add: This is a classified program; outsourcing the build infrastructure is a non-starter.) Interested in any best practices or peripheral guidance you might offer. The build automation issues is one of several overlapping best practices that appear to be missing on the program, but try to keep your answers focused on build infrastructure piece and observations directly related. Cost is not an object. Scalability and ease of retrofitting onto an existing infrastructure are key. JA

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• Hashing 11 byte unique ID to 32 bits or less

  - by MoJo

  I am looking for a way to reduce a 11 byte unique ID to 32 bits or fewer. I am using an Atmel AVR microcontroller that has the ID number burned in at the factory, but because it has to be transmitted very often in a very low power system I want to reduce the length down to 4 bytes or fewer. The ID is guaranteed unique for every microcontroller. It is made up of data from the manufacturing process, basically the coordinates of the silicone on the wafer and the production line that was used. They look like this: 304A34393334-16-11001000 314832383431-0F-09000C00 Obviously the main danger is that by reducing these IDs they become non-unique. Unfortunately I don't have a large enough sample size to test how unique these numbers are. Having said that because there will only be tens of thousands of devices in use and there is secondary information that can be used to help identify them (such as their approximate location, known at the time of communication) collisions might not be too much of an issue if they are few and far between. Is something like MD5 suitable for this? My concern is that the data being hashed is very short, just 11 bytes. Do hash functions work reliably on such short data?

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• Visual Studio 2008 linker wants all symbols to be resolved, not only used ones

  - by user343011

  We recently upgraded to Visual Studio 2008 from 2005, and I think those error started after that. In our solution, we have a multitude of projects. Many of those are utility projects, or projects containing core functionality used by other projects. The output of those is lib files that are linked to when building the projects generating the final binaries using the "Project dependencies..." option. One of the other projects---Let us call it ResultLib---generates a DLL, and it needs one single function from the core project. This function uses only static function from its own source file, but the project in its entirety uses a lot of low-level Windows functions and also imports a DLL---Let us call it Driver.dll. Our problem is that when building ExtLib, the linker complains about a multitude of unresolved externals, for example all functions exported from Driver.dll, since its lib file is not specified when linking. If we try to fix this by adding all lib files used by other projects that use all of the core project, our resulting ResultLib DLL ends up importing Driver.dll and also exporting all functions defined in it. How do we tell Visual Studio to only try to resolve symbols that are actually used?

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• How to debug JBoss out of memory problem?

  - by user561733

  Hello, I am trying to debug a JBoss out of memory problem. When JBoss starts up and runs for a while, it seems to use memory as intended by the startup configuration. However, it seems that when some unknown user action is taken (or the log file grows to a certain size) using the sole web application JBoss is serving up, memory increases dramatically and JBoss freezes. When JBoss freezes, it is difficult to kill the process or do anything because of low memory. When the process is finally killed via a -9 argument and the server is restarted, the log file is very small and only contains outputs from the startup of the newly started process and not any information on why the memory increased so much. This is why it is so hard to debug: server.log does not have information from the killed process. The log is set to grow to 2 GB and the log file for the new process is only about 300 Kb though it grows properly during normal memory circumstances. This is information on the JBoss configuration: JBoss (MX MicroKernel) 4.0.3 JDK 1.6.0 update 22 PermSize=512m MaxPermSize=512m Xms=1024m Xmx=6144m This is basic info on the system: Operating system: CentOS Linux 5.5 Kernel and CPU: Linux 2.6.18-194.26.1.el5 on x86_64 Processor information: Intel(R) Xeon(R) CPU E5420 @ 2.50GHz, 8 cores This is good example information on the system during normal pre-freeze conditions a few minutes after the jboss service startup: Running processes: 183 CPU load averages: 0.16 (1 min) 0.06 (5 mins) 0.09 (15 mins) CPU usage: 0% user, 0% kernel, 1% IO, 99% idle Real memory: 17.38 GB total, 2.46 GB used Virtual memory: 19.59 GB total, 0 bytes used Local disk space: 113.37 GB total, 11.89 GB used When JBoss freezes, system information looks like this: Running processes: 225 CPU load averages: 4.66 (1 min) 1.84 (5 mins) 0.93 (15 mins) CPU usage: 0% user, 12% kernel, 73% IO, 15% idle Real memory: 17.38 GB total, 17.18 GB used Virtual memory: 19.59 GB total, 706.29 MB used Local disk space: 113.37 GB total, 11.89 GB used

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• iPhone OpenGLES: Textures are consuming too much memory and the program crashes with signal "0"

  - by CustomAppsMan

  I am not sure what the problem is. My app is running fine on the simulator but when I try to run it on the iPhone it crashes during debugging or without debugging with signal "0". I am using the Texture2D.m and OpenGLES2DView.m from the examples provided by Apple. I profiled the app on the iPhone with Instruments using the Memory tracer from the Library and when the app died the final memory consumed was about 60Mb real and 90+Mb virtual. Is there some other problem or is the iPhone just killing the application because it has consumed too much memory? If you need any information please state it and I will try to provide it. I am creating thousands of textures at load time which is why the memory consumption is so high. Really cant do anything about reducing the number of pics being loaded. I was running before on just UIImage but it was giving me really low frame rates. I read on this site that I should use OpenGLES for higher frame rates. Also sub question is there any way not to use UIImage to load the png file and then use the Texture class provided to create the texture for OpenGLES functions to use it for drawing? Is there some function in OpenGLES which will create a texture straight from a png file?

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• gcc compilations (sometimes) result in cpu underload

  - by confusedCoder

  I have a larger C++ program which starts out by reading thousands of small text files into memory and storing data in stl containers. This takes about a minute. Periodically, a compilation will exhibit behavior where that initial part of the program will run at about 22-23% CPU load. Once that step is over, it goes back to ~100% CPU. It is more likely to happen with O2 flag turned on but not consistently. It happens even less often with the -p flag which makes it almost impossible to profile. I did capture it once but the gprof output wasn't helpful - everything runs with the same relative speed just at low cpu usage. I am quite certain that this has nothing to do with multiple cores. I do have a quad-core cpu, and most of the code is multi-threaded, but I tested this issue running a single thread. Also, when I run the problematic step in multiple threads, each thread only runs at ~20% CPU. I apologize ahead of time for the vagueness of the question but I have run out of ideas as to how to troubleshoot it further, so any hints might be helpful. UPDATE: Just to make sure it's clear, the problematic part of the code does sometimes (~30-40% of the compilations) run at 100% CPU, so it's hard to buy the (otherwise reasonable) argument that I/O is the bottleneck

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