linux

Why the creators of Windows and Linux systems chose different ways to support Unicode?

As far as I know Linux chose backward compatibility of UTF-8, whereas Windows added completely new API functions for UTF-16 (ending with "W"). Could these decisions be different? Which one proved better? ...

Linux ext3 readdir and concurrent updates

Dear all, we are receiving about 10000 messages per hour. We store them as individual files in hourly directories on an ext3 filesystem. The file name includes a sequence number. We use rsync to mirror these files every 20 seconds at another location (via a SAN, but that doesn't matter). Sometimes an rsync run picks up files n-3, n-2, ...

ubuntu: sem_timedwait not waking (C)

I have 3 processes which need to be synchronized. Process one does something then wakes process two and sleeps, which does something then wakes process three and sleeps, which does something and wakes process one and sleeps. The whole loop is timed to run around 25hz (caused by an external sync into process one before it triggers proces...

linux dot utility (with xhprof)

i installed the xhprof profiling extension for php Everything is fine except for the callgraph.php file, it returns: failed to shell execute cmd=" dot -Tpng" so i checked and the dot utility wasn't installed, so i installed it. it appears to be running fine from the command line so i ran the scritp again, same error: failed to shell e...

Do I need JDK or only JRE?

I use Solr in my website, and now I am about to configure my VPS account. I am at the stage where I need to install java in order to make Solr work. Now, I only plan on running solr, and using it as it is (I have no java programming skills at all), so my Q is, do I need the entire JDK which includes JRE, or is JRE enough? Thanks BTW:...

Running Solr on VPS problems

I have a VPS with Ubuntu OS. I run solr om my local machine (windows xp laptop) just fine. I have configured Jetty, and Solr just the same way as on my computer, but on the server. I have also downloaded the JRE and installed it on the server. However, whenever I try to run the start.jar file, the PuTTY terminal shows a bunch of text...

Ajax based progress bar

I am developing a progress bar using Ajax. My client side code is working fine, but I have issue at server side. I am using C based CGI. if(i == inc && pb_inc<=100) { fptr = fopen("progress_bar.txt", "w"); fprintf(fptr,"%d", j); fclose(fptr); pb_inc++; } basically I am increasing progress bar after certain number of bytes. What I see ...

Methods of sending web-generated config files to servers and restarting services.

Hi, We're writing a web-based tool to configure our services provided by multiple servers. This includes interfaces configuration, dhcp configs etc. etc. Having configs in database and views that generate proper output, how to send it/make it available for servers? I'm thinking about sending it through scp and invoking reload command t...

Linux / Ubuntu command similar to Windows cmd "start"?

From cmd on windows, you can type "start filename" and an action will be taken based on the programs associated with the type of the file. EXEs will launch, JPEGs will have an associated file viewer opened, etc.. Is there a way to do this on Linux / Ubuntu? ...

Creating a Linux Desktop Envoriment

Suppose I want to create my own desktop envoriment for Linux, without X. Like Google with the Android did. Where do I start? Is it actually a normal application that just draws stuff, and starts after the kernel boot? And how does it draw it? Using OpenGL or is there something more generic? And graphics drivers, how is it going? You shou...

require 'rubygems' for linux but not in windows. why? and can I fix this?

I'm setting up a Linux development environment. After installing Ruby and RubyGems, I quickly found out that I need to require 'rubygems' in order to use gems, whereas I do not need to do this in Windows Vista. Is there anything I can do to fix this? Should I even be worrying about it? ...

PHP: Can pcntl_alarm() and socket_select() peacefully exist in the same thread?

I have a PHP CLI script mostly written that functions as a chat server for chat clients to connect to (don't ask me why I'm doing it in PHP, thats another story haha). My script utilizes the socket_select() function to hang execution until something happens on a socket, at which point it wakes up, processes the event, and waits until t...

Random-access archive for Unix use

I'm looking for a good format for archiving entire file-systems of old Linux computers. TAR.GZ The tar.gz format is great for archiving files with UNIX-style attributes, but since the compression is applied across the entire archive, the design precludes random-access. Instead, if you want to access a file at the end of the archive, you...

How do I play with test command properly?

[root@jiaoyou ~]# test 1 = 1 -a 0 = 1 [root@jiaoyou ~]# if [1 = 1 -a 0 = 1]then echo 1;else echo 2;fi -bash: syntax error near unexpected token `else' Why test doesn't give any output and the if statement fails? Can someone point out what's wrong here? UPDATE Can someone illustrate how to simulate complex expressions like 1=1 and (0...

How to repackage NVIDIA .run drivers into .deb with DKMS

At present, Ubuntu offers the 195.36.24 drivers as nvidia-current in their repository. This packaged driver is pretty cool as it uses DKMS so you don't have to keep reinstalling the driver after a new kernel version. The NVIDIA .run package drivers are at version 257 (beta) but they don't use DKMS so the graphics screws up every time a ...

Linux - specific API reference

Hello! Where can I find centralized and complete documentation aboput Linux - specific API? I'm preparing Linux port of my application and i want to use as much Linux - specific features as it's possible. So far I found that Linux provide epoll and inotify API, which are great news for me, because my program works as network server and...

how to see contents of a.out file?

The executable file of c++ will contain linkers, modules and others, i would like to look into its contents, i'm using linux, how can i view contents of a.out? which command should use to browse a.out, text editors wont show the contents...... ...

Bash: infinite sleep

I use startx to start X which will evaluate my .xinitrc. In my .xinitrc I start my window manager using /usr/bin/mywm. Now, if I kill my WM (in order to f.e. test some other WM), X will terminate too because the .xinitrc script reached EOF. So I added this at the end of my .xinitrc: while true; do sleep 10000; done This way X won't te...

Undefined symbol ‘IA__gdk_drag_context_get_device’

I get those two errors when trying to compile GTK+: ../../gdk/gdkaliasdef.c:1142: error: ‘gdk_drag_context_get_device’ aliased to undefined symbol ‘IA__gdk_drag_context_get_device’ ../../gdk/gdkaliasdef.c:1145: error: ‘gdk_drag_context_set_device’ aliased to undefined symbol ‘IA__gdk_drag_context_set_device’ those lines are: #undef g...

Solr; What does this mean?

At the end of the README.txt file which is located in the example directory under solr, I find this line: NOTE: This Solr example server references SolrCell jars outside of the server directory with statements in the solrconfig.xml. If you make a copy of this example server and wish to use the ExtractingRequestHandler (SolrCell...