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  • smtp sasl authentication failure

    - by cromestant
    hello, I have configured and fixed almost all the problems with my postfix +courier + mysql setup for virtual mailboxes. I can now receive mail and send it from webmail (squirrel). BUT, what I can't do is authenticate from outside client. Since my isp blocks port 25 I setup postfix to work on 1025 for smtp and setup verbose loging. Here is the verbose log of a failed authentication process LOG Authentication for imap and pop3 seem to be working but this one is not. Here is the postconf -n output. Also through mysql I can verify that it is trying to validate through the system, running a query that returns the encrypted password stored in the database. I can't seem to find the error for this. thank you in advance

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  • Why does DNS work the way it does?

    - by sabof
    This is a Canonical Question about DNS (Domain Name Service). If my understanding of the DNS system is correct, the .com registry holds a table that maps domains (www.example.com) to DNS servers. What is the advantage? Why not map directly to an IP address? If the only record that needs to change when I am configuring a DNS server to point to a different IP address, is located at the DNS server, why isn't the process instant? If the only reason for the delay are DNS caches, is it possible to bypass them, so I can see what is happening in real time?

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  • ArrayIndexOutOfBounds exception in CoyoteAdapter.normalize()

    - by Alex
    I'm working with an application that uses Tomcat 5.0.28 for sending and receiving AS2 messages. At times, it's throwing the following exception on receiving an MDN receipt for a transmission: An exception or error occurred in the container during the request processing java.lang.ArrayIndexOutOfBoundsException: 0 at org.apache.coyote.tomcat5.CoyoteAdapter.normalize(CoyoteAdapter.java:483) at org.apache.coyote.tomcat5.CoyoteAdapter.postParseRequest(CoyoteAdapter.java:239) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:158) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683) at java.lang.Thread.run(Unknown Source) I've found a report of this issue regarding v. 5.0.25 (here), with a followup note that it was resolved in 5.0.27. However, as above, the version number used in this app is 5.0.28. Any suggestions for how to find out what might be triggering this error?

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  • Determinism in multiplayer simulation with Box2D, and single computer

    - by Jake
    I wrote a small test car driving multiplayer game with Box2D using TCP server-client communcations. I ran 1 instance of server.exe and 2 instance of client.exe on the same machine that I code and compile the executables. I type inputs (WASD for a simple car movement) into one of the 2 clients and I can get both clients to update the simulation. There are 2 cars in the simulation. As long as the cars do not collide, I get the same identical output on both client.exe. I can run the car(s) around for as long as I could they still update the same. However, if I start to collide the cars, very quickly they go out of sync. My tools: Windows 7, C++, MSVS 2010, Box2D, freeGlut. My Psuedocode: // client.exe void timer(int value) { tcpServer.send(my_inputs); foreach(i = player including myself) inputs[i] = tcpServer.receive(); foreach(i = player including myself) players[i].process(inputs[i]); myb2World.step(33, 8, 6); // Box2D world step simulation foreach(i = player including myself) renderer.render(player[i]); glutTimerFunc(33, timer, 0); } // server.exe void serviceloop { while(all clients alive) { foreach(c = clients) tcpClients[c].receive(&inputs[c]); // send input of each client to all clients foreach(source = clients) { foreach(dest = clients) { tcpClients[dest].send(inputs[source]); } } } } I have read all over the internet and SE the following claims (paraphrased): Box2D is deterministic as long as floating point architecture/implementation is the same. (For any deterministic engine) Determinism is gauranteed if playback of recorded inputs is on the same machine with exe compiled using same compiler and machine. Additionally my server.exe and client.exe gameloop is single thread with blocking socket calls and fixed time step. Question: Can anyone explain what I did wrong to get different Box2D output?

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  • Will BIOS boot mode Ubuntu install be able to boot when firmware "Fast Boot" is "Ultra Fast"?

    - by Pro Backup
    I have an AsRock mainboard with UEFI BIOS P1.50 02/14/2014. The firmware "Fast Boot" option is set to "Fast", Boot Option #1 is set to "AHCI P4: OCZ-VERT...": this is BIOS not UEFI boot. This boot disk has an MBR partitioning scheme (# parted -l | grep Partition\ Table:). Therefore Ubuntu 14.04 is installed in BIOS/CMS (Grub-PC) mode. The Ubuntu boot process ends in a text console (no GUI). There is no external graphics card in use. The stock Ubuntu kernel is replaced with Ubuntu supplied mainline 3.16.0-031600rc6-generic. dmesg outputs lines containing BIOS, like: SMBIOS 2.7 present Calgary: detecting Calgary via BIOS EBDA area Calgary: Unable to locate Rio Grande table in EBDA - bailing! [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored BIOS EDD facility v0.16 2004-Jun-25, 0 devices found The ASRock BIOS it selves display this help text for "Ultra Fast - Fast Boot": Ultra Fast mode is only supported by Windows 8 and the VBIOS must support UEFI GOP if you are using an external graphics card. Please notice that Ultra Fast mode will boot so fast that the only way to enter this UEFI Setup Utility is to Clear CMOS or run the Restart to UEFI utility in Windows. Assumptions: I suspect after changing UEFI setting "Fast Boot" to "Ultra Fast" that the machine will no longer boot into Ubuntu's console. I expect when first exchanging "Grub-pc" with "Grub-efi", that the machine will still be able to boot to a grub menu (thus allowing to change the "Fast Boot" setting back to "Fast" without clearing CMOS). Are these two "Fast Boot" assumptions correct, and/or, may I expect Ubuntu 14.04 running mainline kernel 3.16rc6 and Grub-efi to still boot to console after enabling UEFI Ultra Fast Boot?

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  • How to make Microsoft Keyboard special keys run osascript commands on OSX?

    - by t-a-w
    I'm trying to make (1) special key open new terminal window. I bound it to file /Users/taw/bin/new_term, which contains: #!/bin/sh exec osascript -e 'tell application "Terminal" to do script "cd ."' This does the trick, except it also opens a Terminal window with this (even though Terminal.app is configured to always close windows when processes finish): Last login: Thu Mar 11 19:41:29 on ttys000 /Users/taw/bin/new_term ; exit; ~$ /Users/taw/bin/new_term ; exit; tab 1 logout [Process completed] How do I make it all work correctly? (possibly using a way different that what I've been attempting so far)

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  • Booting Ubuntu 12.04 in Unity the Windows Theme & Icon Theme reversed back to and always locked to Ubuntu default

    - by Antonio
    I did set up last year Faience-Ocre as my Icon Theme and Adwaita Cupertino L Unity as my Windows Theme (the GTK+ thme was unchanged to Adwaita (default)). It has worked perfectly well until 3 days ago when starting my PC I saw the Ubuntu default showing up for Windows & Icon Theme. I noticed that at start-up the disk access LED is not lit up continuously as before but at moment stops reading for a few seconds (up to 15 s) then complete the disk reading process. When all was working well this LED would lit up continuously. Another thing is that GNOME applications are as well not working well as previously Nautilus and Gedit now don't use the global menu in the system bar but a local window menu. Nautilus - Nemo before the incident Nautilus - Nemo now ... I did open dconf to check the desktop settings in org-gnome-desktop-wm-preferences and everything is looking good. When I change the settings in the app Advanced Settings in the Theme folder I see the respective value changing in dconf. However, there is no change on my desktop. It looks like it's crippled and GNOME related. [Update 1]: I have the same defect as referenced @ ubuntu theme suddenly changed to default and it's not coming back! instead of my GTK theme I get a classic, Windows-95-like grayish theme ... However one of the solution mentionned: http://www.webupd8.org/2011/06/fix-ubuntu-linux-mint-theme-changing-to.html is not working at all, even for 20 s up to 60 s delay.

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  • Ubuntu-installer fails preseed configuration file

    - by user76171
    I try to install Ubuntu 12.04 over network unattended. I installed a DHCP server (Dnsmasq), a TFTP server (tftpd-hpa), I got the netboot.tar.gz archive with the pxelinux.0 file, the pxelinux.cfg directory, the linux kernel and the initrd.gz image and I put a preseed file into my web server. Dnsmasq, tftpd-hpa, pxelinux and Apache are all on the same machine. The PCs MB doesn’t support PXE, so I use iPXE and boot it from a CD. The PC gets an IP from the DHCP, then iPXE loads #pxelinux.cfg/default, which I edited like this: timeout 5 prompt 0 default install label install kernel ubuntu-installer/i386/linux append vga=normal locale=en_GB setup/layoutcode=sl_SI console-setup/layoutcode=sl_SI netcfg/choose_interface=auto initrd=ubuntu-installer/i386/initrd.gz netcfg/get_hostname=ubuntux preseed/url=#http://192.168.10.10/ins/preseed.cfg Then it loads the linux kernel and the initrd.gz image. Then I got a question: Detect keyboard layout? I desided to bother with this later. So I answer No, and then twice on Englishjust to get trough and then I get to the error: The installer failed to process the preconfiguration file from #http://192.168.10.10/ins/preseeed.cfg. The file may be corrupt. I created the file myself and copied the d-I commands into it. I also tried to get the preseed.cfg over a web browser and it works fine. So why is the installer failing?

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  • Fine-tuning a LNMP stack

    - by Norman
    I'm in the process of setting up a server with 4GB RAM and 2 CPUs. The stack will be CentOS + NGINX + MySQL + PHP (with APC) and spawn-fcgi. It will be used to serve 10 Wordpress blogs, 3 of which receive about 20,000 hits per day. Each Wordpress instance is equipped with the W3 TotalCache. I have a few variables to play with: NGINX (How many worker_processes, worker_connections, etc) PHP (What parameters in php.ini should I change? What about apc?) Spawn-fcgi (Right now I have 6 php-cgi spawned. How many of them should I have?) I realize it's hard to tell without testing, but if you could please provide me with some ballpark numbers, that would be helpful too.

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  • What is the impact of Windows 8 with UEFI on normal users?

    - by Sam
    I am a normal man-in-the-street computer user and so do not really understand what this is about, but I want to. Can someone please explain to me if: The Windows 8/UEFI secure boot thing will make it impossible to run normal/legacy applications in Windows 8 (as they will be unsigned)? It will turn Windows into an Apple-like system where only Microsoft approved applications can be run? As I say, I'm a normal user, and that is the overall impression I have from reading all the blogs, etc about it. If, on the other hand, all it does is make sure the system is booting a signed OS, how does this prevent malware (which is what at least two Microsoft blogs that I read seemed to be saying), given that most malware is not part of the boot process? The only way I can see this making sense is if it is ensuring that all OS components are signed. Is that it? Like I say, I'm a mortal, so please don't get technical on me, but rather explain how it will affect me, the user.

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  • How do I backup my Ubuntu 9.10 system and then restore it to a new machine with different hardware?

    - by EricJLN
    I have a nicely configured Ubuntu 9.10 machine, with crossover linux (from Codeweavers) installed. I have the Nvidia drivers installed. Everything is just as I want it. Now I want to move to a new machine with different hardware: different sized hard drive, different size RAM, different video card, etc. I tried the technique suggested on Ubuntu forums, "Howto: Backup and restore your system!". The results: New system complains about swap not being found New system complains about not finding Nvidia hardware, and I can't open the System-Administration-Hardware Drivers application (i.e., /usr/bin/jockey-gtk) to fix the problem. As result of nvidia, X-Windows is throwing errors, and the on screen process for fixing X-Windows isn't working. How do I restore a backup of my old system, including my Crossover Linux installation, to a new machine with different hardware installed?

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  • How to get partition information from non-booting server?

    - by gravyface
    Need to manually rebuild a mirrored array on a server and am in the process of reinstalling SBS 2003 on it. However, it's a Dell server, and know that there's the Dell FAT32 diagnostics partition, a system partition, and a data partition, but do not know the size of each. Planning on reinstalling SBS 2003, all applications on the server, and then doing a System State restore, but figured that not having the correct partitions will cause some grief: am I right? Almost thinking that the size of the partitions shouldn't matter, but not positive. Question: should I care about the size of the partition? If so, how can I get this partition information from a non-booting drive? We have an Acronis image of the one working disk and the partitions are mounted/viewable in Explorer on a workstation, but I'm not sure where the Logical Disk Manager/Disk Management data is stored and/or if there's a way to retrieve it without having a working Windows installation.

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  • Software development is (mostly) a trade, and what to do about it

    - by Jeff
    (This is another cross-post from my personal blog. I don’t even remember when I first started to write it, but I feel like my opinion is well enough baked to share.) I've been sitting on this for a long time, particularly as my opinion has changed dramatically over the last few years. That I've encountered more crappy code than maintainable, quality code in my career as a software developer only reinforces what I'm about to say. Software development is just a trade for most, and not a huge academic endeavor. For those of you with computer science degrees readying your pitchforks and collecting your algorithm interview questions, let me explain. This is not an assault on your way of life, and if you've been around, you know I'm right about the quality problem. You also know the HR problem is very real, or we wouldn't be paying top dollar for mediocre developers and importing people from all over the world to fill the jobs we can't fill. I'm going to try and outline what I see as some of the problems, and hopefully offer my views on how to address them. The recruiting problem I think a lot of companies are doing it wrong. Over the years, I've had two kinds of interview experiences. The first, and right, kind of experience involves talking about real life achievements, followed by some variation on white boarding in pseudo-code, drafting some basic system architecture, or even sitting down at a comprooder and pecking out some basic code to tackle a real problem. I can honestly say that I've had a job offer for every interview like this, save for one, because the task was to debug something and they didn't like me asking where to look ("everyone else in the company died in a plane crash"). The other interview experience, the wrong one, involves the classic torture test designed to make the candidate feel stupid and do things they never have, and never will do in their job. First they will question you about obscure academic material you've never seen, or don't care to remember. Then they'll ask you to white board some ridiculous algorithm involving prime numbers or some kind of string manipulation no one would ever do. In fact, if you had to do something like this, you'd Google for a solution instead of waste time on a solved problem. Some will tell you that the academic gauntlet interview is useful to see how people respond to pressure, how they engage in complex logic, etc. That might be true, unless of course you have someone who brushed up on the solutions to the silly puzzles, and they're playing you. But here's the real reason why the second experience is wrong: You're evaluating for things that aren't the job. These might have been useful tactics when you had to hire people to write machine language or C++, but in a world dominated by managed code in C#, or Java, people aren't managing memory or trying to be smarter than the compilers. They're using well known design patterns and techniques to deliver software. More to the point, these puzzle gauntlets don't evaluate things that really matter. They don't get into code design, issues of loose coupling and testability, knowledge of the basics around HTTP, or anything else that relates to building supportable and maintainable software. The first situation, involving real life problems, gives you an immediate idea of how the candidate will work out. One of my favorite experiences as an interviewee was with a guy who literally brought his work from that day and asked me how to deal with his problem. I had to demonstrate how I would design a class, make sure the unit testing coverage was solid, etc. I worked at that company for two years. So stop looking for algorithm puzzle crunchers, because a guy who can crush a Fibonacci sequence might also be a guy who writes a class with 5,000 lines of untestable code. Fashion your interview process on ways to reveal a developer who can write supportable and maintainable code. I would even go so far as to let them use the Google. If they want to cut-and-paste code, pass on them, but if they're looking for context or straight class references, hire them, because they're going to be life-long learners. The contractor problem I doubt anyone has ever worked in a place where contractors weren't used. The use of contractors seems like an obvious way to control costs. You can hire someone for just as long as you need them and then let them go. You can even give them the work that no one else wants to do. In practice, most places I've worked have retained and budgeted for the contractor year-round, meaning that the $90+ per hour they're paying (of which half goes to the person) would have been better spent on a full-time person with a $100k salary and benefits. But it's not even the cost that is an issue. It's the quality of work delivered. The accountability of a contractor is totally transient. They only need to deliver for as long as you keep them around, and chances are they'll never again touch the code. There's no incentive for them to get things right, there's little incentive to understand your system or learn anything. At the risk of making an unfair generalization, craftsmanship doesn't matter to most contractors. The education problem I don't know what they teach in college CS courses. I've believed for most of my adult life that a college degree was an essential part of being successful. Of course I would hold that bias, since I did it, and have the paper to show for it in a box somewhere in the basement. My first clue that maybe this wasn't a fully qualified opinion comes from the fact that I double-majored in journalism and radio/TV, not computer science. Eventually I worked with people who skipped college entirely, many of them at Microsoft. Then I worked with people who had a masters degree who sucked at writing code, next to the high school diploma types that rock it every day. I still think there's a lot to be said for the social development of someone who has the on-campus experience, but for software developers, college might not matter. As I mentioned before, most of us are not writing compilers, and we never will. It's actually surprising to find how many people are self-taught in the art of software development, and that should reveal some interesting truths about how we learn. The first truth is that we learn largely out of necessity. There's something that we want to achieve, so we do what I call just-in-time learning to meet those goals. We acquire knowledge when we need it. So what about the gaps in our knowledge? That's where the most valuable education occurs, via our mentors. They're the people we work next to and the people who write blogs. They are critical to our professional development. They don't need to be an encyclopedia of jargon, but they understand the craft. Even at this stage of my career, I probably can't tell you what SOLID stands for, but you can bet that I practice the principles behind that acronym every day. That comes from experience, augmented by my peers. I'm hell bent on passing that experience to others. Process issues If you're a manager type and don't do much in the way of writing code these days (shame on you for not messing around at least), then your job is to isolate your tradespeople from nonsense, while bringing your business into the realm of modern software development. That doesn't mean you slap up a white board with sticky notes and start calling yourself agile, it means getting all of your stakeholders to understand that frequent delivery of quality software is the best way to deal with change and evolving expectations. It also means that you have to play technical overlord to make sure the education and quality issues are dealt with. That's why I make the crack about sticky notes, because without the right technique being practiced among your code monkeys, you're just a guy with sticky notes. You're asking your business to accept frequent and iterative delivery, now make sure that the folks writing the code can handle the same thing. This means unit testing, the right instrumentation, integration tests, automated builds and deployments... all of the stuff that makes it easy to see when change breaks stuff. The prognosis I strongly believe that education is the most important part of what we do. I'm encouraged by things like The Starter League, and it's the kind of thing I'd love to see more of. I would go as far as to say I'd love to start something like this internally at an existing company. Most of all though, I can't emphasize enough how important it is that we mentor each other and share our knowledge. If you have people on your staff who don't want to learn, fire them. Seriously, get rid of them. A few months working with someone really good, who understands the craftsmanship required to build supportable and maintainable code, will change that person forever and increase their value immeasurably.

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  • getaddrinfo: command not found

    - by jebbie
    I've installed a new Ubuntu 12.04 on an AWS EC2 instance and everything worked fine till now. I followed the instructions in this great tutorial: http://www.exratione.com/2012/05/a-mailserver-on-ubuntu-1204-postfix-dovecot-mysql/ Now i'm on the point "installing monit" and when i restart the service i get this error message now: monit: Cannot translate '(none)' to FQDN name -- Name or service not known I started googling and someone is writing there, that monit uses getaddrinfo in his startup-process to determine the hostname. Ok, so i thought i try out on myself what is getaddrinfo delivering, and then i got: getaddrinfo: command not found I guess, something is missing on my system. Can anyone help?

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  • What's the best way to generate an NPC's face using web technologies?

    - by Vael Victus
    I'm in the process of creating a web app. I have many randomly-generated non-player characters in a database. I can pull a lot of information about them - their height, weight, down to eye color, hair color, and hair style. For this, I am solely interested in generating a graphical representation of the face. Currently the information is displayed with text in the nicest way possible, but I believe it's worth generating these faces for a more... human experience. Problem is, I'm not artist. I wouldn't mind commissioning an artist for this system, but I wouldn't know where to start. Were it 2007, I'd naturally think to myself that using Flash would be the best choice. I'd love to see "breathing" simulated. However, since Flash is on its way out, I'm not sure of a solid solution. With a previous game, I simply used layered .pngs to represent various aspects of the player's body: their armor, the face, the skin color. However, these solutions weren't very dynamic and felt very amateur. I can't go deep into this project feeling like that's an inferior way to present these faces, and I'm certain there's a better way. Can anyone give some suggestion on how to pull this off well?

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  • local install of wp site brought down from host - home page is ok but other pages redirect to wamp config page

    - by jeff
    local install of wp site brought down from host - home page is ok but other pages redirect to wamp config page. I got all local files from host to www dir under local wamp. I got database from host and loaded to new local db and used this tool to adjust site_on_web.com to "localhost/site_on_local" now the home page works great and can login to admin page but when click on reservations page and others of site then site just goes to the wamp server config page even though the url shows correctly as localhost/site_on_local/reservations my htaccess file is this # BEGIN WordPress <IfModule mod_rewrite.c> RewriteEngine On RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L] </IfModule> # END WordPress and rewrite-module is checked in the php-apache-apache modules setting. now when I uncheck the rewrite-module is checked in the php-apache-apache modules setting or I clear out the whole htaccess file then the pages just goto Not Found The requested URL /ritas041214/about-ritas/ was not found on this server. Please help as I am unsure now about my process to move local site up and down and be able to make it work and without this I am lost...

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  • Redirect one input from one terminal to another

    - by Niki Yoshiuchi
    I have sshed into a linux box and I'm using dvtm and bash (although I have also tried this with Gnu screen and bash). I have two terminals, current /dev/pts/29 and /dev/pts/130. I want to redirect the input from one to the other. From what I understand, in /dev/pts/130 I can type: cat </dev/pts/29 And then when I type in /dev/pts/29 the characters I type should show up in /dev/pts/130. However what ends up happening is that every other character I type gets redirected. For example, if I type "hello" I get this: /dev/pts/29 | /dev/pts/130 $ | $ cat </dev/pts/29 $ el | hlo This is really frustrating as I need to do this in order to redirect the io of a process running in gdb (I've tried both run /dev/pts/# and set inferior-tty /dev/pts/# and both resulted in the aforementioned behavior). Am I doing something wrong, or is this a bug in bash/screen/dvtm?

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  • Software management for 2 programmers

    - by kajo
    me and my very good friend do a small bussiness. We have company and we develop web apps using Scala. We have started 3 months ago and we have a lot of work now. We cannot afford to employ another programmer because we can't pay him now. Until now we try to manage entire developing process very simply. We use excel sheets for simple bug tracking and we work on client requests on the fly. We have no plan for next week or something similar. But now I find it very inefficient and useless. I am trying to find some rules or some methodology for small team or for only two guys. For example Scrum is, imo, unadapted for us. There are a lot of roles (ScrumMaster, Product Owner, Team...) and it seems overkill. Can you something advise me? Have you any experiences with software management in small teams? Is any methodology of current agile development fitten for pair of programmers? Is there any software management for simple bug tracking, maybe wiki or time management for two coders? thanks a lot for sharing.

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  • What every beginner should know about website development? [closed]

    - by user975234
    I am a novice at building websites and considering to make one. But there is a lot of confusion that's going on right now. I guess every beginner faces them. Few questions that come up are: I have an idea and a need a website. That's all i know right now. But how do i start ? HTML is for sure the basic language but there are a hell of other technologies too. What is actually asp, php, ruby etc? How do i choose the right one from them? Other than asp, php there is javascript and other languages under the same belt. What are they used for? Hosting. When i am choosing the host, what considerations i have to keep in mind ? What support do i need from them (other than getting some important space obviously!). I am considering of making the website in ruby on rails. I don't know about php and what effect it would have if i choose ruby over php. I thought about ruby just because its new and i dont want to learn some thing "not new"! :P Moreover what is a framework and how does a framework effect my development process? These three questions are just to explain my "confusion" better. There is obviously a lot more to it. Just to try to answer how the flow of website development goes keeping in mind my questions!

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  • Were the first assemblers written in machine code?

    - by The111
    I am reading the book The Elements of Computing Systems: Building a Modern Computer from First Principles, which contains projects encompassing the build of a computer from boolean gates all the way to high level applications (in that order). The current project I'm working on is writing an assembler using a high level language of my choice, to translate from Hack assembly code to Hack machine code (Hack is the name of the hardware platform built in the previous chapters). Although the hardware has all been built in a simulator, I have tried to pretend that I am really constructing each level using only the tools available to me at that point in the real process. That said, it got me thinking. Using a high level language to write my assembler is certainly convenient, but for the very first assembler ever written (i.e. in history), wouldn't it need to be written in machine code, since that's all that existed at the time? And a correlated question... how about today? If a brand new CPU architecture comes out, with a brand new instruction set, and a brand new assembly syntax, how would the assembler be constructed? I'm assuming you could still use an existing high level language to generate binaries for the assembler program, since if you know the syntax of both the assembly and machine languages for your new platform, then the task of writing the assembler is really just a text analysis task and is not inherently related to that platform (i.e. needing to be written in that platform's machine language)... which is the very reason I am able to "cheat" while writing my Hack assembler in 2012, and use some preexisting high level language to help me out.

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  • How do I create my own programming language and a compiler for it

    - by Dave
    I am thorough with programming and have come across languages including BASIC, FORTRAN, COBOL, LISP, LOGO, Java, C++, C, MATLAB, Mathematica, Python, Ruby, Perl, JavaScript, Assembly and so on. I can't understand how people create programming languages and devise compilers for it. I also couldn't understand how people create OS like Windows, Mac, UNIX, DOS and so on. The other thing that is mysterious to me is how people create libraries like OpenGL, OpenCL, OpenCV, Cocoa, MFC and so on. The last thing I am unable to figure out is how scientists devise an assembly language and an assembler for a microprocessor. I would really like to learn all of these stuff and I am 15 years old. I always wanted to be a computer scientist someone like Babbage, Turing, Shannon, or Dennis Ritchie. I have already read Aho's Compiler Design and Tanenbaum's OS concepts book and they all only discuss concepts and code in a high level. They don't go into the details and nuances and how to devise a compiler or operating system. I want a concrete understanding so that I can create one myself and not just an understanding of what a thread, semaphore, process, or parsing is. I asked my brother about all this. He is a SB student in EECS at MIT and hasn't got a clue of how to actually create all these stuff in the real world. All he knows is just an understanding of Compiler Design and OS concepts like the ones that you guys have mentioned (i.e. like Thread, Synchronization, Concurrency, memory management, Lexical Analysis, Intermediate code generation and so on)

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  • Split DC role from existing Exchange 2007 server

    - by Graeme Donaldson
    We currently have a single Exchange 2007 Server on Windows Server 2008. It's also a DC and I'd like to split the DC role to a different box. Is this doable without migrating the mailboxes off to a temporary box, re-installing and migrating back? I.e. can I just demote the server without breaking Exchange completely? I know this was quite painful with Server 2003/Exchange 2003, so I'm trying to get an idea of how much different the process is for Server 2008/Exchange 2007.

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  • nginx server over https using up all available file handles (upd: infinite loop?)

    - by mmr
    Hi all, So I have an nginx server that's working over https with Sinatra. When I try to download a jnlp file in a configuration that works fine over Mongrel and http (no s), the nginx server fails to serve the file with a 504 error. Subsequent checking of the logs states that this error is due to overflowing the available number of file handles, ie, "24: too many open files". Running sudo lsof -p <nginx worker pid> gets me a huge list of files, all looking like: nginx 1771 nobody 11u IPv4 10867997 0t0 TCP localhost:44704->localhost:https (ESTABLISHED) nginx 1771 nobody 12u IPv4 10868113 0t0 TCP localhost:https->localhost:44704 (ESTABLISHED) nginx 1771 nobody 13u IPv4 10868114 0t0 TCP localhost:44705->localhost:https (ESTABLISHED) nginx 1771 nobody 14u IPv4 10868191 0t0 TCP localhost:https->localhost:44705 (ESTABLISHED) nginx 1771 nobody 15u IPv4 10868192 0t0 TCP localhost:44706->localhost:https (ESTABLISHED) nginx 1771 nobody 16u IPv4 10868255 0t0 TCP localhost:https->localhost:44706 (ESTABLISHED) nginx 1771 nobody 17u IPv4 10868256 0t0 TCP localhost:44707->localhost:https (ESTABLISHED) nginx 1771 nobody 18u IPv4 10868330 0t0 TCP localhost:https->localhost:44707 (ESTABLISHED) nginx 1771 nobody 19u IPv4 10868331 0t0 TCP localhost:44708->localhost:https (ESTABLISHED) nginx 1771 nobody 20u IPv4 10868434 0t0 TCP localhost:https->localhost:44708 (ESTABLISHED) Increasing the number of files that can be opened is no help, because then nginx just blows right past that limit. And no wonder, it looks like it's in some kind of loop to pull all available files. Any idea what's going on, and how to fix it? EDIT: nginx 0.7.63, ubuntu linux, sinatra 1.0 EDIT 2: Here's the offending code. It's sinatra serving jnlp, which I finally figured out: get '/uploader' do #read in the launch.jnlp file theJNLP = "" File.open("/launch.jnlp", "r+") do |file| while theTemp = file.gets theJNLP = theJNLP + theTemp end end content_type :jnlp theJNLP end If I serve this with Sinatra via Mongrel and http, everything works fine. If I serve this with Sinatra and nginx via https, I get the above error. All other parts of the website appear to be equivalent. EDIT: I have since upgraded to passenger 2.2.14, ruby 1.9.1, nginx 0.8.40, openssl 1.0.0a, and no change. EDIT: The culprit appears to be infinite redirects due to using SSL. I don't know how to fix this, other than hosting the jnlp file in the root directory of the server (which I'd rather not do, since it limits me to one jnlp-based app at a time). The relevant lines from nginx.conf: # HTTPS server # server { listen 443; server_name MyServer.org root /My/Root/Dir; passenger_enabled on; expires 1d; proxy_set_header X-FORWARDED_PROTO https; proxy_set_header X_FORWARDED_PROTO https;#the almighty google is not clear on which to use location /upload { proxy_pass https://127.0.0.1:443; } } The funny thing about this is, first, I was putting the jnlp into a directory called 'uploader', not 'upload', but that still appeared to trigger the problem, since that proxy_pass directive appeared in the logs. Second, again, moving the jnlp into root avoided the problem, because there wasn't any of this proxying due to ssl. So, how can I avoid the infinite proxy_pass loop in nginx?

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  • How I Work: Staying Productive Whilst Traveling

    - by BuckWoody
    I travel a lot. Not like some folks that are gone every week, mind you, although in the last month I’ve been to: Cambridge, UK; Anchorage, AK; San Jose, CA; Copenhagen, DK, Boston, MA; and I’m currently en-route to Anaheim, CA.  While this many places in a month is a bit unusual for me, I would say I travel frequently. I’ve travelled most of my 28+ years in IT, and at one time was a consultant traveling weekly.   With that much time away from my primary work location, I have to find ways to stay productive. Some might say “just rest – take a nap!” – but I’m not able to do that. For one thing, I’m a very light sleeper and I’ve never slept on a plane - even a 30+ hour trip to New Zealand in Business Class - so that just isn’t option. I also am not always in the plane, of course. There’s the hotel, the taxi/bus/train, the airport and then all that over again when I arrive. Since my regular jobs have many demands, I have to get work done.   Note: No, I’m not always focused on work. I need downtime just like everyone else. Sometimes I just think, watch a movie or listen to tunes – and I give myself permission to do that anytime – sometimes the whole trip. I have too fewheartbeats left in life to only focus on work – it’s just not that important, and neither am I. Some of these tasks are letters to friends and family, or other personal things. What I’m talking about here is a plan, not some task list I have to follow. When I get to the location I’m traveling to, I always build in as much time as I can to ensure I enjoy those sights and the people I’m with. I would find traveling to be a waste if not for that.   The Unrealistic Expectation As I would evaluate the trip I was taking – say a 6-8 hour flight – I would expect to get 10-12 hours of work done. After all, there’s the time at the airport, the taxi and so on, and then of course the time in the air with all of the room, power, internet and everything else I needed to get my work done. I would pile up tasks at home, pack my bags, and head happily to the magical land of the TSA.   Right. On return from the trip, I had accomplished little, had more e-mails and other work that had piled up, and I was tired, hungry, and unorganized. This had to change. So, I decided to do three things: Segment my work Set realistic expectations Plan accordingly  Segmenting By Available Resources The first task was to decide what kind of work I could do in each location – if any. I found that I was dependent on a few things to get work done, such as power, the Internet, and a place to sit down. Before I fly, I take some time at home to get all of the work I’d like to accomplish while away segmented into these areas, and print that out on paper, which goes in my suit-coat pocket along with a mechanical pencil. I print my tickets, and I’m all set for the adventure ahead. Then I simply do each kind of work whenever I’m in that situation. No power There are certain times when I don’t have power available. But not only that, I might not even be able to use most of my electronics. So I now schedule as many phone calls as I can for the taxi/bus/train ride and the airports as I can. I have a paper notebook (Moleskine, of course) and a pencil and I print out any notes or numbers I need prior to the trip. Once I’m airborne or at the airport, I work on my laptop. I check and respond to e-mails, create slides, write code, do architecture, whatever I can.  If I can’t use any electronics, or once the power runs out, I schedule time for reading. I can read at the airport or anywhere, actually, even in-flight or any other transport. I “read with a pencil”, meaning I take a lot of notes, which I liketo put in OneNote, but since in most cases I don’t have power, I use the Moleskine to do that. Speaking of which, sometimes as I’m thinking I come up with new topics, ideas, blog posts, or things to teach in my classes. Once again I take out the notebook and write it down. All of these notes get a check-mark when I get back to the office and transfer the writing to OneNote. I’ve tried those “smart pens” and so on to automate this, but it just never works out. Pencil and paper are just fine. As I mentioned, sometime I just need to think. I’ll do nothing, and let my mind wander, thinking of nothing in particular, or some math problem or science question I’m interested in. My only issue with this is that I communicate tothink, and I don’t want to drive people crazy by being that guy that won’t shut up, so I think in a different way. Power, but no Internet or Phone If I have power but no Internet or phone, I focus on the laptop and the tablet as before, and I also recharge my other gadgets. Power, Internet, Phone and a Place to Work At first I thought that when I arrived at the hotel or event I could get the same amount of work done that I do at the office. Not so. There’s simply too many distractions, things you need, or other issues that allow this. Of course, Ican work on any device, read, think, write or whatever, but I am simply not as productive as I am in my home office. So I plan for about 25-50% as much work getting done in this environment as I think I could really do. I’ve done some measurements, and this holds out to be true almost every time. The key is that I re-set my expectations (and my co-worker’s expectations as well) that this is the case. I use the Out-Of-Office notices to let people know that I’m just not going to be 100% at this time – it’s hard for everyone, but it’s more honest and realistic, and I’d rather they know that – and that I realize that – than to let them think I’m totally available. Because I’m not – I’m traveling. I don’t tend to put too much detail, because after all I don’t necessarily want to let people know when I’m not home :) but I do think it’s important to let people that depend on my know that I’ll get back with them later. I hope this helps you think through your own methodology of staying productive when you travel. Or perhaps you just go offline, and don’t worry about any of this – good for you! That’s completely valid as well.   (Oh, and yes, I wrote this at 35K feet, on Alaska Airlines on a trip. :)  Practice what you preach, Buck.)

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  • Quickbooks 2009 2010

    - by Bronwyn
    I have configured my bank account within quickbooks to import bank statements. I have wxported the bank statement. Then used the convert process available within QB to convert. The file name shows the bsb then some other figures and then the account number. However it will not import. I am wondering how ot make this work. Can I change the file name to match my QB account details and thus enable the importing. This is a technical question. Many thanks Bronwyn

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