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  • What are the different branches of Programming? [closed]

    - by clueless
    I just want a very general overview about what are the actual 'branches' of programming in the industry. What are different paths one can choose as a programmer and what are the common frameworks/languages/platforms in those paths. Currently I'm well versed with C/C++ and Python and I'm a beginner with Django. I want to know this because I can't decide what to proceed with after this, which route to take. Hope it's not a very general question. Thanks!

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  • Programming for Digital frames

    - by spartan2417
    A project has recently come to my attention but i have no idea where to start or even if its possible. The idea revolves around programming a clock that is displayed inside a digital photo frame. The user would then be able to put different pictures corresponding to different times inside a usb pen for example, which would load as soon as you put the usb in. The project itself would be a really neat project - if it was just on a computer. I have no idea if what im talking about it even possible on a digital photo frame and if it is what language? Anyone who has any input at all would be great. My current idea is to maybe have a small device at the back, SSD, that runs the program through a screen, completely by passing standard digital photo frames, again though i dont know how to begin with this. And yes ive tried google (although it helps to know what to google).

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  • How are Programming Languages Designed?

    - by RectangleTangle
    After doing a bit of programming, I've become quite curious on language design itself. I'm still a novice (I've been doing it for about a year), so the majority of my code pertains to only two fields (GUI design in Python and basic algorithms in C/C++). I have become intrigued with how the actual languages themselves are written. I mean this in both senses. Such as how it was literally written (ie, what language the language was written in). As well as various features like white spacing (Python) or object orientation (C++ and Python). Where would one start learning how to write a language? What are some of the fundamentals of language design, things that would make it a "complete" language?

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  • Programming language for simple program?

    - by jamherst
    I am wondering about which programming languages people see fit to create a program idea that I had. I am looking to create a fairly simple program whose main functions are adding to, managing, and searching through a database of people, all through a polished GUI. It will be for use in the business world, so I think Windows would be the priority, but Mac and Linux support wouldn't be bad. Also, eventually I would like to add the ability for an instance of one program on a computer to interact with other instances on the same network, mainly through the sharing of a database. Most of my experience is in Java, but I don't particularly like the appearance of Java GUIs, so I'm looking for an alternative. I noticed that a lot of people have suggested C++ or C# in similar posts, so what are some of the advantages/disadvantages of one or both if that is your suggestion. Thanks for any help in advance.

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  • Programming C++ using Qt4

    - by DaGhostman Dimitrov
    Hey guys I am really new to the C++ programing I have a little knowledge in C and a bit more in C++, but I do not know them enough to call myself a programmer. I am working as a PHP Web Developer I like being a crafts man and creating things so that is the reason to combine the programming with web development. I think that I could really benefit from both of them and so... My question is: Is it a good Idea to learn C++ with Qt or not? Can you give me pros and cons of both? Note: I do not want to become a programmer and give up the web development I want to combine them both.

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  • Looking for a dynamic programming solution

    - by krammer
    Given a sequence of integers in range 1 to n. Each number can appear at most once. Let there be a symbol X in the sequence which means remove the minimum element from the list. There can be an arbitrarily number of X in the sequence. Example: 1,3,4,X,5,2,X The output is 1,2. We need to find the best way to perform this operation. The solution I have been thinking is: Scan the sequence from left to right and count number of X which takes O(n) time. Perform partial sorting and find the k smallest elements (k = number of X) which takes O(n+klogk) time using median of medians. Is there a better way to solve this problem using dynamic programming or any other way ?

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  • Beginner's steps to game programming [on hold]

    - by CodeTrasher
    I have graduated from university less than 6 months ago and became a B.Eng in Software Engineering. I have moderate understanding of programming experience from languages like C++, Java and C#. But mostly on simple desktop and mobile applications. I've tried some simple Pong-like games but never finished even the smallest game. I have a couple of nice ideas growing (IMO, at least...) in my mind but don't really know where to begin. 2D is way to go, of course, at the beginning. I just want to hear from more experienced game devs how they started out. Should I make a rough outline of the core idea and mechanics and start working on a prototype of core gameplay? Or should I just practice more by making Pong, Asteroids and that sort of games and get an understanding of those before moving on? Thanks to all!

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  • Programming error in 'aptdaemon' [closed]

    - by Real
    Using Ubuntu 11.10 While performing updates through the update manager I get the following message: An unhandlable error occured There seems to be a programming error in aptdaemon, the software that allows you to install/remove software and to perform other package management related tasks. Details Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 968, in simulate trans.unauthenticated = self._simulate_helper(trans) File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1092, in _simulate_helper return depends, self._cache.required_download, \ File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 235, in required_download pm.get_archives(fetcher, self._list, self._records) SystemError: E:Method has died unexpectedly!, E:Sub-process returned an error code (100), E:Method /usr/lib/apt/methods/ did not start correctly Tried some of the fixes that were posted but did not work. What shall I do to fix this issue?

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  • What programming language matches this description? [on hold]

    - by Benubird
    I am looking for a functional language that is basically dynamic programming - i.e. one where functions are first-class objects - but where all function calls are asynchronous by default; i.e. you define function X(a,b) = (Y(a)+Z(b)), and when X() is called, it sees it is waiting for the return from two functions, runs one in the current thread, and spawns a new thread to run the other. The future is very much parallel processing; multiple cores, multiple machines, the internet of things, etc. and I was wondering if there was a language specifically designed to make this kind of parallelization easy. I currently have only used imperative languages (c, php, java, ruby, etc), so I don't know anything about what kind of functional languages are available.

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  • Why do I get disk I/O errors booting the 3.2 kernel on a xen vps server?

    - by Doug
    I have a xen vps, which I just upgraded to the new LTS 12 Precise Pangolin. However, I see this error on booting: [ 12.848076] end_request: I/O error, dev xvda, sector 12841 [ 12.848093] end_request: I/O error, dev xvda, sector 12841 [ 12.848103] Buffer I/O error on device xvda1, logical block 1605 [ 12.848110] lost page write due to I/O error on xvda1 [ 12.848129] Aborting journal on device xvda1. Results in / being mounted read-only. Reboot: [ 3.087257] EXT3-fs (xvda1): warning: ext3_clear_journal_err: Marking fs in need of filesystem check. [ 3.087677] EXT3-fs (xvda1): recovery complete [ 3.088514] EXT3-fs (xvda1): mounted filesystem with ordered data mode Begin: Running /scripts/local-bottom ... done. done. Begin: Running /scripts/init-bottom ... done. fsck from util-linux 2.20.1 PRGMRDISK1 contains a file system with errors, check forced. Checking disk drives for errors. This may take several minutes. Press C to cancel all checks in progress PRGMRDISK1: ***** REBOOT LINUX ***** PRGMRDISK1: 371152/6001184 files (2.8% non-contiguous), 4727949/12000000 blocks mountall: fsck / [308] terminated with status 3 mountall: System must be rebooted: / [ 151.566949] Restarting system. Name ID Mem VCPUs State Time(s) shadowmint 236 2048 1 --p--- 0.0 Reboot - back to 1. This is definitely an issue with the 3.2 kernel, because booting the 3.0.0 or 2.6.38 kernel series make this issue magically disappear. I'm certain this is some kind of weird xen thing, but no idea. Anyone? Anyhow, until this is resolve I strongly recommend against upgrading if you're running a xen server.

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  • Is copy paste programming bad ?

    - by ring bearer
    With plain google as well as google code search tools it is easy to find how to program using some resource or solve certain problems ( such as a Java class, or a ftp block in perl etc) and so developers are so tempted to just purely copy paste the code (in a way re-use) - is this an incompetency? I have done this myself though I think I am a better programmer than many others I have seen. Who has the time to RTFM? In this age of information abundance, I do not think that copy paste programming is bad. Isn't that what sites like stackoverflow do anyway? People ask - ok here is my problem - how to solve it? now someone will post complete code and the person who asked the question would simply copy paste the most voted answer. No matter how small the problem is. I am working with a bunch of young coders who heavily rely on internet to get their job done. I see convenience (for example, you may be quite good with algorithms and such but you may not know how to use a BufferedReader in Java - would you read complete Javadoc for BufferedReader or look up some example of using it somewhere??) in copy pasting and modifying code to get the job done. What are the real dangers of copy paste coding that can impact their competency?

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  • Functional programming and stateful algorithms

    - by bigstones
    I'm learning functional programming with Haskell. In the meantime I'm studying Automata theory and as the two seem to fit well together I'm writing a small library to play with automata. Here's the problem that made me ask the question. While studying a way to evaluate a state's reachability I got the idea that a simple recursive algorithm would be quite inefficient, because some paths might share some states and I might end up evaluating them more than once. For example, here, evaluating reachability of g from a, I'd have to exclude f both while checking the path through d and c: So my idea is that an algorithm working in parallel on many paths and updating a shared record of excluded states might be great, but that's too much for me. I've seen that in some simple recursion cases one can pass state as an argument, and that's what I have to do here, because I pass forward the list of states I've gone through to avoid loops. But is there a way to pass that list also backwards, like returning it in a tuple together with the boolean result of my canReach function? (although this feels a bit forced) Besides the validity of my example case, what other techniques are available to solve this kind of problems? I feel like these must be common enough that there have to be solutions like what happens with fold* or map. So far, reading learnyouahaskell.com I didn't find any, but consider I haven't touched monads yet. (if interested, I posted my code on codereview)

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  • Thread safe GUI programming

    - by James
    I have been programming Java with swing for a couple of years now, and always accepted that GUI interactions had to happen on the Event Dispatch Thread. I recently started to use GTK+ for C applications and was unsurprised to find that GUI interactions had to be called on gtk_main. Similarly, I looked at SWT to see in what ways it was different to Swing and to see if it was worth using, and again found the UI thread idea, and I am sure that these 3 are not the only toolkits to use this model. I was wondering if there is a reason for this design i.e. what is the reason for keeping UI modifications isolated to a single thread. I can see why some modifications may cause issues (like modifying a list while it is being drawn), but I do not see why these concerns pass on to the user of the API. Is there a limit imposed by an operating system? Is there a good reason these concerns are not 'hidden' (i.e. some form of synchronization that is invisible to the user)? Is there any (even purely conceptual) way of creating a thread safe graphics library, or is such a thing actually impossible? I found this http://blogs.operationaldynamics.com/andrew/software/gnome-desktop/gtk-thread-awareness which seems to describe GTK differently to how I understood it (although my understanding was the same as many people's) How does this differ to other toolkits? Is it possible to implement this in Swing (as the EDT model does not actually prevent access from other threads, it just often leads to Exceptions)

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  • C# Threading Background Process - Programming - How to?

    - by Magic
    Hello...I have been given the horrible task of doing this. Launch the website Take a screenshot Fill in the form details, click on Next Take a screenshot ... ... ... Rinse. Repeat. Now, with various combinations, this comes up to 300 screenshots. And I have to do this for 4 different browsers. Chrome, Firefox, IE 6 and IE 7. I cannot use tools which will capture the screenshot and store them, such as, SnagIT. I need to take a screenshot, copy it to a Word Document and take the second screenshot and take it to a Word Document. I thought, I will write a tiny utility which will help me do this. Here is the requirement spec that I put up for it - An executable which once launched seats itself in the System Tray. While it is active, all instances of Key Press (Print Scrn), it should write the contents to a Word Document as defined (either a default path or a user defined one). Save the document periodically. Now, my question is - if I am going to develop this using C# (Winforms application), how do I go about doing this. I can do a fair bit of C# programming and I am willing to learn. But I am not able to locate the references for how to do a background process so that it runs in the background. And while it runs, it has to capture the Print Scrn command. Can you folks point me to the right material where I can learn this? Theoretical references should suffice. But if there are practical references, then nothing like it. Thanks!

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  • Setting up Netbeans/Eclipse for Linux Kernel Development

    - by red.october
    Hi: I'm doing some Linux kernel development, and I'm trying to use Netbeans. Despite declared support for Make-based C projects, I cannot create a fully functional Netbeans project. This is despite compiling having Netbeans analyze a kernel binary that was compiled with full debugging information. Problems include: files are wrongly excluded: Some files are incorrectly greyed out in the project, which means Netbeans does not believe they should be included in the project, when in fact they are compiled into the kernel. The main problem is that Netbeans will miss any definitions that exist in these files, such as data structures and functions, but also miss macro definitions. cannot find definitions: Pretty self-explanatory - often times, Netbeans cannot find the definition of something. This is partly a result of the above problem. can't find header files: self-explanatory I'm wondering if anyone has had success with setting up Netbeans for Linux kernel development, and if so, what settings they used. Ultimately, I'm looking for Netbeans to be able to either parse the Makefile (preferred) or extract the debug information from the binary (less desirable, since this can significantly slow down compilation), and automatically determine which files are actually compiled and which macros are actually defined. Then, based on this, I would like to be able to find the definitions of any data structure, variable, function, etc. and have complete auto-completion. Let me preface this question with some points: I'm not interested in solutions involving Vim/Emacs. I know some people like them, but I'm not one of them. As the title suggest, I would be also happy to know how to set-up Eclipse to do what I need While I would prefer perfect coverage, something that only misses one in a million definitions is obviously fine SO's useful "Related Questions" feature has informed me that the following question is related: http://stackoverflow.com/questions/149321/what-ide-would-be-good-for-linux-kernel-driver-development. Upon reading it, the question is more of a comparison between IDE's, whereas I'm looking for how to set-up a particular IDE. Even so, the user Wade Mealing seems to have some expertise in working with Eclipse on this kind of development, so I would certainly appreciate his (and of course all of your) answers. Cheers

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  • System locking up with suspicious messages about hard disk

    - by Chris Conway
    My system has started behaving strangely, intermittently locking up. I see messages like the following in syslog: Nov 18 22:22:00 claypool kernel: [ 3428.078156] ata3.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Nov 18 22:22:00 claypool kernel: [ 3428.078163] ata3.00: irq_stat 0x40000000 Nov 18 22:22:00 claypool kernel: [ 3428.078167] sr 2:0:0:0: CDB: Test Unit Ready: 00 00 00 00 00 00 Nov 18 22:22:00 claypool kernel: [ 3428.078182] ata3.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0 Nov 18 22:22:00 claypool kernel: [ 3428.078184] res 50/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error) Nov 18 22:22:00 claypool kernel: [ 3428.078188] ata3.00: status: { DRDY } Nov 18 22:22:00 claypool kernel: [ 3428.080887] ata3.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 Nov 18 22:22:00 claypool kernel: [ 3428.080890] ata3.00: irq_stat 0x40000000 Nov 18 22:22:00 claypool kernel: [ 3428.080893] sr 2:0:0:0: CDB: Test Unit Ready: 00 00 00 00 00 00 Nov 18 22:22:00 claypool kernel: [ 3428.080905] ata3.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0 Nov 18 22:22:00 claypool kernel: [ 3428.080906] res 50/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error) Nov 18 22:22:00 claypool kernel: [ 3428.080910] ata3.00: status: { DRDY } And then this: Nov 18 23:13:56 claypool kernel: [ 6544.000798] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen Nov 18 23:13:56 claypool kernel: [ 6544.000804] ata1.00: failed command: FLUSH CACHE EXT Nov 18 23:13:56 claypool kernel: [ 6544.000814] ata1.00: cmd ea/00:00:00:00:00/00:00:00:00:00/a0 tag 0 Nov 18 23:13:56 claypool kernel: [ 6544.000815] res 40/00:00:00:4f:c2/00:00:00:00:00/40 Emask 0x4 (timeout) Nov 18 23:13:56 claypool kernel: [ 6544.000819] ata1.00: status: { DRDY } Nov 18 23:13:56 claypool kernel: [ 6544.000825] ata1: hard resetting link Nov 18 23:14:01 claypool kernel: [ 6549.360324] ata1: link is slow to respond, please be patient (ready=0) Nov 18 23:14:06 claypool kernel: [ 6554.008091] ata1: COMRESET failed (errno=-16) Nov 18 23:14:06 claypool kernel: [ 6554.008103] ata1: hard resetting link Nov 18 23:14:11 claypool kernel: [ 6559.372246] ata1: link is slow to respond, please be patient (ready=0) Nov 18 23:14:16 claypool kernel: [ 6564.020228] ata1: COMRESET failed (errno=-16) Nov 18 23:14:16 claypool kernel: [ 6564.020235] ata1: hard resetting link Nov 18 23:14:21 claypool kernel: [ 6569.380109] ata1: link is slow to respond, please be patient (ready=0) Nov 18 23:14:31 claypool kernel: [ 6579.460243] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Nov 18 23:14:31 claypool kernel: [ 6579.486595] ata1.00: configured for UDMA/133 Nov 18 23:14:31 claypool kernel: [ 6579.486601] ata1.00: retrying FLUSH 0xea Emask 0x4 Nov 18 23:14:31 claypool kernel: [ 6579.486939] ata1.00: device reported invalid CHS sector 0 Nov 18 23:14:31 claypool kernel: [ 6579.486952] ata1: EH complete Nov 18 23:17:01 claypool CRON[3910]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly) Nov 18 23:17:01 claypool CRON[3908]: (CRON) error (grandchild #3910 failed with exit status 1) Nov 18 23:17:01 claypool postfix/sendmail[3925]: fatal: open /etc/postfix/main.cf: No such file or directory Nov 18 23:17:01 claypool CRON[3908]: (root) MAIL (mailed 1 byte of output; but got status 0x004b, #012) Nov 18 23:39:01 claypool CRON[4200]: (root) CMD ( [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -type f -cmin +$(/usr/lib/php5/maxlifetime) -print0 | xargs -n 200 -r -0 rm) There are no messages marked after 23:39. When I next tried to use the machine, it would not return from the screensaver (blank screen), nor switch to another terminal, and I had to hard reboot it. [UPDATE] The output of smartctl is here. I had trouble getting this, because / is being mounted read-only (?!), which prevents most applications from running. Also, it may not be related, but I have the following worrying messages in dmesg: [ 10.084596] k8temp 0000:00:18.3: Temperature readouts might be wrong - check erratum #141 [ 10.098477] i2c i2c-0: nForce2 SMBus adapter at 0x600 [ 10.098483] ACPI: resource nForce2_smbus [io 0x0700-0x073f] conflicts with ACPI region SM00 [??? 0x00000700-0x0000073f flags 0x30] [ 10.098486] ACPI: This conflict may cause random problems and system instability [ 10.098487] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [ 10.098509] i2c i2c-1: nForce2 SMBus adapter at 0x700 [ 10.112570] Linux agpgart interface v0.103 [ 10.155329] atk: Resources not safely usable due to acpi_enforce_resources kernel parameter [ 10.161506] it87: Found IT8712F chip at 0x290, revision 8 [ 10.161517] it87: VID is disabled (pins used for GPIO) [ 10.161527] it87: in3 is VCC (+5V) [ 10.161528] it87: in7 is VCCH (+5V Stand-By) [ 10.161560] ACPI: resource it87 [io 0x0295-0x0296] conflicts with ACPI region ECRE [??? 0x00000290-0x000002af flags 0x45] [ 10.161562] ACPI: This conflict may cause random problems and system instability [ 10.161564] ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver [UPDATE 2] I swapped in a new SATA cable, per Phil's suggestion. The current output of smartctl is here, if it helps. [UPDATE 3] I don't think the cable fixed it. The system hasn't locked up yet, but my media player crashed a few minutes ago and I have the following in the syslog: Nov 20 16:07:17 claypool kernel: [ 2294.400033] ata1: link is slow to respond, please be patient (ready=0) Nov 20 16:07:47 claypool kernel: [ 2324.084581] ata1: COMRESET failed (errno=-16) Nov 20 16:07:47 claypool kernel: [ 2324.084588] ata1: limiting SATA link speed to 1.5 Gbps Nov 20 16:07:47 claypool kernel: [ 2324.084592] ata1: hard resetting link I get the following response from smartctl: $ sudo smartctl -a /dev/sda [sudo] password for chris: sudo: Can't open /var/lib/sudo/chris/0: Read-only file system smartctl 5.40 2010-03-16 r3077 [i686-pc-linux-gnu] (local build) Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net Device: /0:0:0:0 Version: scsiModePageOffset: response length too short, resp_len=47 offset=50 bd_len=46 >> Terminate command early due to bad response to IEC mode page A mandatory SMART command failed: exiting. To continue, add one or more '-T permissive' options.

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  • Virtualbox on Ubuntu 12.04 and 3.5 kernel

    - by kas
    I have installed the 3.5 kernel under Ubuntu 12.04. When I install virtualbox I recieve the following error. Setting up virtualbox (4.1.12-dfsg-2ubuntu0.2) ... * Stopping VirtualBox kernel modules [ OK ] * Starting VirtualBox kernel modules * No suitable module for running kernel found [fail] invoke-rc.d: initscript virtualbox, action "restart" failed. Processing triggers for python-central ... Setting up virtualbox-dkms (4.1.12-dfsg-2ubuntu0.2) ... Loading new virtualbox-4.1.12 DKMS files... First Installation: checking all kernels... Building only for 3.5.0-18-generic Building initial module for 3.5.0-18-generic Error! Bad return status for module build on kernel: 3.5.0-18-generic (x86_64) Consult /var/lib/dkms/virtualbox/4.1.12/build/make.log for more information. * Stopping VirtualBox kernel modules [ OK ] * Starting VirtualBox kernel modules * No suitable module for running kernel found [fail] invoke-rc.d: initscript virtualbox, action "restart" failed. Setting up virtualbox-qt (4.1.12-dfsg-2ubuntu0.2) ... Does anyone know how I might be able to resolve this? Edit -- Here is the make.log DKMS make.log for virtualbox-4.1.12 for kernel 3.5.0-18-generic (x86_64) Mon Nov 19 12:12:23 EST 2012 make: Entering directory `/usr/src/linux-headers-3.5.0-18-generic' LD /var/lib/dkms/virtualbox/4.1.12/build/built-in.o LD /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/built-in.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/linux/SUPDrv-linux.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/SUPDrv.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/SUPDrvSem.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/alloc-r0drv.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/initterm-r0drv.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/memobj-r0drv.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/mpnotification-r0drv.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/powernotification-r0drv.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/assert-r0drv-linux.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/alloc-r0drv-linux.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/initterm-r0drv-linux.o CC [M] /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/memobj-r0drv-linux.o /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/memobj-r0drv-linux.c: In function ‘rtR0MemObjLinuxDoMmap’: /var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/memobj-r0drv-linux.c:1150:9: error: implicit declaration of function ‘do_mmap’ [-Werror=implicit-function-declaration] cc1: some warnings being treated as errors make[2]: *** [/var/lib/dkms/virtualbox/4.1.12/build/vboxdrv/r0drv/linux/memobj-r0drv-linux.o] Error 1 make[1]: *** [/var/lib/dkms/virtualbox/4.1.12/build/vboxdrv] Error 2 make: *** [_module_/var/lib/dkms/virtualbox/4.1.12/build] Error 2 make: Leaving directory `/usr/src/linux-headers-3.5.0-18-generic'

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  • How to get better at solving Dynamic programming problems

    - by newbie
    I recently came across this question: "You are given a boolean expression consisting of a string of the symbols 'true', 'false', 'and', 'or', and 'xor'. Count the number of ways to parenthesize the expression such that it will evaluate to true. For example, there is only 1 way to parenthesize 'true and false xor true' such that it evaluates to true." I knew it is a dynamic programming problem so i tried to come up with a solution on my own which is as follows. Suppose we have a expression as A.B.C.....D where '.' represents any of the operations and, or, xor and the capital letters represent true or false. Lets say the number of ways for this expression of size K to produce a true is N. when a new boolean value E is added to this expression there are 2 ways to parenthesize this new expression 1. ((A.B.C.....D).E) ie. with all possible parenthesizations of A.B.C.....D we add E at the end. 2. (A.B.C.(D.E)) ie. evaluate D.E first and then find the number of ways this expression of size K can produce true. suppose T[K] is the number of ways the expression with size K produces true then T[k]=val1+val2+val3 where val1,val2,val3 are calculated as follows. 1)when E is grouped with D. i)It does not change the value of D ii)it inverses the value of D in the first case val1=T[K]=N.( As this reduces to the initial A.B.C....D expression ). In the second case re-evaluate dp[K] with value of D reversed and that is val1. 2)when E is grouped with the whole expression. //val2 contains the number of 'true' E will produce with expressions which gave 'true' among all parenthesized instances of A.B.C.......D i) if true.E = true then val2 = N ii) if true.E = false then val2 = 0 //val3 contains the number of 'true' E will produce with expressions which gave 'false' among all parenthesized instances of A.B.C.......D iii) if false.E=true then val3=( 2^(K-2) - N ) = M ie. number of ways the expression with size K produces a false [ 2^(K-2) is the number of ways to parenthesize an expression of size K ]. iv) if false.E=false then val3 = 0 This is the basic idea i had in mind but when i checked for its solution http://people.csail.mit.edu/bdean/6.046/dp/dp_9.swf the approach there was completely different. Can someone tell me what am I doing wrong and how can i get better at solving DP so that I can come up with solutions like the one given above myself. Thanks in advance.

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  • HTML5 game programming style

    - by fnx
    I am currently trying learn javascript in form of HTML5 games. Stuff that I've done so far isn't too fancy since I'm still a beginner. My biggest concern so far has been that I don't really know what is the best way to code since I don't know the pros and cons of different methods, nor I've found any good explanations about them. So far I've been using the worst (and propably easiest) method of all (I think) since I'm just starting out, for example like this: var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); var width = 640; var height = 480; var player = new Player("pic.png", 100, 100, ...); also some other global vars... function Player(imgSrc, x, y, ...) { this.sprite = new Image(); this.sprite.src = imgSrc; this.x = x; this.y = y; ... } Player.prototype.update = function() { // blah blah... } Player.prototype.draw = function() { // yada yada... } function GameLoop() { player.update(); player.draw(); setTimeout(GameLoop, 1000/60); } However, I've seen a few examples on the internet that look interesting, but I don't know how to properly code in these styles, nor do I know if there are names for them. These might not be the best examples but hopefully you'll get the point: 1: Game = { variables: { width: 640, height: 480, stuff: value }, init: function(args) { // some stuff here }, update: function(args) { // some stuff here }, draw: function(args) { // some stuff here }, }; // from http://codeincomplete.com/posts/2011/5/14/javascript_pong/ 2: function Game() { this.Initialize = function () { } this.LoadContent = function () { this.GameLoop = setInterval(this.RunGameLoop, this.DrawInterval); } this.RunGameLoop = function (game) { this.Update(); this.Draw(); } this.Update = function () { // update } this.Draw = function () { // draw game frame } } // from http://www.felinesoft.com/blog/index.php/2010/09/accelerated-game-programming-with-html5-and-canvas/ 3: var engine = {}; engine.canvas = document.getElementById('canvas'); engine.ctx = engine.canvas.getContext('2d'); engine.map = {}; engine.map.draw = function() { // draw map } engine.player = {}; engine.player.draw = function() { // draw player } // from http://that-guy.net/articles/ So I guess my questions are: Which is most CPU efficient, is there any difference between these styles at runtime? Which one allows for easy expandability? Which one is the most safe, or at least harder to hack? Are there any good websites where stuff like this is explained? or... Does it all come to just personal preferance? :)

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  • Learning by doing (and programming by trial and error)

    - by AlexBottoni
    How do you learn a new platform/toolkit while producing working code and keeping your codebase clean? When I know what I can do with the underlying platform and toolkit, I usually do this: I create a new branch (with GIT, in my case) I write a few unit tests (with JUnit, for example) I write my code until it passes my tests So far, so good. The problem is that very often I do not know what I can do with the toolkit because it is brand new to me. I work as a consulant so I cannot have my preferred language/platform/toolkit. I have to cope with whatever the customer uses for the task at hand. Most often, I have to deal (often in a hurry) with a large toolkit that I know very little so I'm forced to "learn by doing" (actually, programming by "trial and error") and this makes me anxious. Please note that, at some point in the learning process, usually I already have: read one or more five-stars books followed one or more web tutorials (writing working code a line at a time) created a couple of small experimental projects with my IDE (IntelliJ IDEA, at the moment. I use Eclipse, Netbeans and others, as well.) Despite all my efforts, at this point usually I can just have a coarse understanding of the platform/toolkit I have to use. I cannot yet grasp each and every detail. This means that each and every new feature that involves some data preparation and some non-trivial algorithm is a pain to implement and requires a lot of trial-and-error. Unfortunately, working by trial-and-error is neither safe nor easy. Actually, this is the phase that makes me most anxious: experimenting with a new toolkit while producing working code and keeping my codebase clean. Usually, at this stage I cannot use the Eclipse Scrapbook because the code I have to write is already too large and complex for this small tool. In the same way, I cannot use any more an indipendent small project for my experiments because I need to try the new code in place. I can just write my code in place and rely on GIT for a safe bail-out. This makes me anxious because this kind of intertwined, half-ripe code can rapidly become incredibly hard to manage. How do you face this phase of the development process? How do you learn-by-doing without making a mess of your codebase? Any tips&tricks, best practice or something like that?

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  • User to kernel mode big picture?

    - by fsdfa
    I've to implement a char device, a LKM. I know some basics about OS, but I feel I don't have the big picture. In a C programm, when I call a syscall what I think it happens is that the CPU is changed to ring0, then goes to the syscall vector and jumps to a kernel memmory space function that handle it. (I think that it does int 0x80 and in eax is the offset of the syscall vector, not sure). Then, I'm in the syscall itself, but I guess that for the kernel is the same process that was before, only that it is in kernel mode, I mean the current PCB is the process that called the syscall. So far... so good?, correct me if something is wrong. Others questions... how can I write/read in process memory?. If in the syscall handler I refer to address, say, 0xbfffffff. What it means that address? physical one? Some virtual kernel one?

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  • How can I remove old kernels/install new ones when /boot is full?

    - by Marcel
    I know this question is asked many times before, however with me it is just a bit different I guess. # df -h Filesystem Size Used Avail Use% Mounted on /dev/sda3 224G 5.2G 208G 3% / udev 1.9G 4.0K 1.9G 1% /dev tmpfs 777M 260K 777M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1.9G 0 1.9G 0% /run/shm /dev/sda2 90M 88M 0 100% /boot /dev/sda6 1.9G 514M 1.3G 29% /tmp My boot partition is full. Current Kernel: # uname -r 3.2.0-35-generic All Kernels: # dpkg --list | grep linux-image ii linux-image-3.2.0-32-generic 3.2.0-32.51 Linux kernel image for version 3.2.0 on 64 bit x86 SMP ii linux-image-3.2.0-34-generic 3.2.0-34.53 Linux kernel image for version 3.2.0 on 64 bit x86 SMP ii linux-image-3.2.0-35-generic 3.2.0-35.55 Linux kernel image for version 3.2.0 on 64 bit x86 SMP iF linux-image-3.2.0-37-generic 3.2.0-37.58 Linux kernel image for version 3.2.0 on 64 bit x86 SMP iF linux-image-3.2.0-38-generic 3.2.0-38.60 Linux kernel image for version 3.2.0 on 64 bit x86 SMP iU linux-image-generic 3.2.0.37.45 Generic Linux kernel image So I thought of removing the 3.2.0.32-generic kernel with: # sudo apt-get purge linux-image-3.2.0-32-generic Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: linux-generic : Depends: linux-headers-generic (= 3.2.0.37.45) but 3.2.0.38.46 is to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). No success. When I try apt-get -f install it also fails: # apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required: linux-headers-3.2.0-34 linux-headers-3.2.0-35 linux-headers-3.2.0-34-generic linux-headers-3.2.0-35-generic Use 'apt-get autoremove' to remove them. The following extra packages will be installed: linux-generic linux-image-generic The following packages will be upgraded: linux-generic linux-image-generic 2 upgraded, 0 newly installed, 0 to remove and 9 not upgraded. 5 not fully installed or removed. Need to get 0 B/4,334 B of archives. After this operation, 0 B of additional disk space will be used. Do you want to continue [Y/n]? y Setting up initramfs-tools (0.99ubuntu13.1) ... update-initramfs: deferring update (trigger activated) Setting up linux-image-3.2.0-37-generic (3.2.0-37.58) ... Running depmod. update-initramfs: deferring update (hook will be called later) The link /initrd.img is a dangling linkto /boot/initrd.img-3.2.0-38-generic Examining /etc/kernel/postinst.d. run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.2.0-37-generic /boot/vmlinuz-3.2.0-37-generic update-initramfs: Generating /boot/initrd.img-3.2.0-37-generic gzip: stdout: No space left on device E: mkinitramfs failure cpio 141 gzip 1 update-initramfs: failed for /boot/initrd.img-3.2.0-37-generic with 1. run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1 Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-3.2.0-37-generic.postinst line 1010. dpkg: error processing linux-image-3.2.0-37-generic (--configure): subprocess installed post-installation script returned error exit status 2 Setting up linux-image-3.2.0-38-generic (3.2.0-38.60) ... Running depmod. update-initramfs: deferring update (hook will be called later) The link /initrd.img is a dangling linkto /boot/initrd.img-3.2.0-37-generic Examining /etc/kernel/postinst.d. run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.2.0-38-generic /boot/vmlinuz-3.2.0-38-generic update-initramfs: Generating /boot/initrd.img-3.2.0-38-generic gzip: stdout: No space left on device E: mkinitramfs failure cpio 141 gzip 1 update-initramfs: failed for /boot/initrd.img-3.2.0-38-generic with 1. run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1 Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-3.2.0-38-generic.postinst line 1010. dpkg: error processing linux-image-3.2.0-38-generic (--configure): subprocess installed post-installation script returned error exit status 2 dpkg: dependency problems prevent configuration of linux-image-generic: linux-image-generic depends on linux-image-3.2.0-37-generic; however: Package linux-image-3.2.0-37-generic is not configured yet. dpkg: error processing linux-image-generic (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of linux-generic: linux-generic depends on linux-image-generic (= 3.2.0.37.45); however: Package linux-image-generic is not configured yet. linux-generic depends on linux-headers-generic (= 3.2.0.37.45); however: Version of linux-headers-generic on system is 3.2.0.38.46. dpkg: error processing linux-generic (--configure): dependency problems - leaving unconfigured Processing triggers for initramfs-tools ... No apport report written because the error message indicates its a followup error from a previous failure. No apport report written because MaxReports is reached already update-initramfs: Generating /boot/initrd.img-3.2.0-35-generic gzip: stdout: No space left on device E: mkinitramfs failure cpio 141 gzip 1 update-initramfs: failed for /boot/initrd.img-3.2.0-35-generic with 1. dpkg: error processing initramfs-tools (--configure): subprocess installed post-installation script returned error exit status 1 No apport report written because MaxReports is reached already Errors were encountered while processing: linux-image-3.2.0-37-generic linux-image-3.2.0-38-generic linux-image-generic linux-generic initramfs-tools E: Sub-process /usr/bin/dpkg returned an error code (1) Any help would really be appreciated. Update: I did: sudo rm /boot/*-3.2.0-32-generic /boot/*-3.2.0-34-generic After that the following problem with apt-get -f install: root@localhost:/# apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: linux-generic The following packages will be upgraded: linux-generic 1 upgraded, 0 newly installed, 0 to remove and 9 not upgraded. 1 not fully installed or removed. Need to get 0 B/1,722 B of archives. After this operation, 0 B of additional disk space will be used. Do you want to continue [Y/n]? y dpkg: dependency problems prevent configuration of linux-generic: linux-generic depends on linux-image-generic (= 3.2.0.37.45); however: Version of linux-image-generic on system is 3.2.0.38.46. linux-generic depends on linux-headers-generic (= 3.2.0.37.45); however: Version of linux-headers-generic on system is 3.2.0.38.46. dpkg: error processing linux-generic (--configure): dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure. Errors were encountered while processing: linux-generic E: Sub-process /usr/bin/dpkg returned an error code (1)

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  • Kernel panic while loading Mac OS X on VMWare

    - by Vladimir Gritsenko
    I have Mac OS X 10.6.3 and VMWare 7.1. Trying to run the OS X doesn't work - shortly after booting VMWare announces the machine's death with this pop-up message: The CPU has been disabled by the guest operating system. You will need to power off or reset the virtual machine at this point. The console has a more interesting announcement: The real-time clock was not properly initialized on your system! With a dump of the detected CPU speed (~2.9 GHz), FSB (~94 MHz) and bus ratio (31). Somehow, the code that panics is documented in an accidental .diff file here. Apparently, it commits seppuku if the bus ratio is greater than 30. I underclocked my E6500 to a slower speed, but this apparently didn't make any difference. I can think of two possibilities right now: The CPU info being read is constant, and defines the maximum ability of the CPU. In which case it appears I'm screwed. VMWare presents its own CPU info to the machine, which I can perhaps somehow change. If so, how? If these sound completely off, that's because I'm a real newbie in these matters. Here's hoping you guys can show me the light :-)

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  • FreeBSD 8 Kernel Configuration Error Using the VESA Option

    - by gvkv
    I'm trying to reconfigure FreeBSD 8 (amd64) to allow for a high resolution terminal by following these instructions. The problem is that when I add the two lines: options VESA options SC_PIXEL_MODE and try to build: make buildkernel KERNCONF=VESAKERN I get the following error: /usr/src/sys/amd64/conf/VESAKERN: unknown option "VESA" and I have no idea why.

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  • Linux Kernel Messages: ata1.00: status: { DRDY ERR }

    - by PM
    I am receiving a lot of these messages. Is my HD going to die tomorrow morning? ata1: link is slow to respond, please be patient (ready=0) ata1: device not ready (errno=-16), forcing hardreset ata1: soft resetting link ata1: clearing spurious IRQ ata1: clearing spurious IRQ ata1: clearing spurious IRQ ata1.00: configured for UDMA/33 ata1: EH complete ata1.00: qc timeout (cmd 0xa0) ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen ata1.00: cmd a0/00:00:00:00:00/00:00:00:00:00/a0 tag 0 cdb 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 res 51/20:03:00:00:00/00:00:00:00:00/a0 Emask 0x5 (timeout)

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