I have recently messed up my Debian Squeeze installation. (click for more). I fixed audio but my battery state indicator and touchpad isn't working. In my attempt to fix this I observed that Kernel version of my system is different from the build os version. This is the out put of Xorg :1 -configure

root@debian-box:/boot# Xorg :1 -configure

X.Org X Server 1.7.7
Release Date: 2010-05-04
X Protocol Version 11, Revision 0
Build Operating System: Linux i686 Debian
Current Operating System: Linux debian-box 2.6.32-5-686 #1 SMP Tue Mar 8 21:36:00 UTC 2011 i686
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.32-5-686 root=UUID=df9afc0c-27af-42b2-95d7-a7944f3bac70 ro quiet
Build Date: 19 February 2011  02:37:36PM
xorg-server 2:1.7.7-13 (Cyril Brulebois ) 
  • @giles: This has nothing to do with compiling or building. Please correct me if I am wrong. I just want to know what does difference in Build OS version and kernel version means – Kumar Apr 9 '11 at 15:44

No, there's absolutely no reason why you should build X (or most programs) on the same operating system that you'll run it on. It's often more difficult, occasionally even impossible, to build software for a different processor architecture (amd64/arm/ppc/x86/…). Building for a different operating system is easier, and the precise kernel version is completely irrelevant (unless you're building kernel modules).

(Then you might wonder why the information is included… I wonder too. I suspect it's a roundabout way of providing information about what compiler version and development packages were used for building, by indicating a probable distribution and version indication.)

  • Is that first sentence backwards? – Thanatos Feb 13 '14 at 23:39
  • @Thanatos Why? I don't see anything wrong with it. – Gilles 'SO- stop being evil' Feb 14 '14 at 0:00
  • It seems to imply that you should not build on the same OS you'll run on; this is what I do all day on Linux. – Thanatos Feb 14 '14 at 0:42
  • Not that you should not, but that you don't have to. – Gilles 'SO- stop being evil' Feb 14 '14 at 0:47

"Build OS version" refers to the OS used when compiling the X.Org server and "Current OS version" refers to your specific machine.

If you do:

 uname -a

the output should match "Current Operating System:".


That information is more geared for developers, not so much for helping a "user" root cause problems. Historically, X "users" were able to build and fix their own bugs, and a lot of the code/interface/docs assume that kind of audience (X11 protocol was released in 1987!).

Specifically, as an X developer, you'd be able to see, "oh, this is the version I built 20 minutes ago, where's the version I just built?" It's not so helpful when you're using pre-built binaries that were built by say, the Debian team, 5 years ago.


As long as the system calls handled by the kernel don't change (too much), the kernel on which a piece of sofware was built is largely irrelevant. But X is intimately tied to the kernel, so on Linux it has a rather more intimate relationship with the kernel than "regular" userland programs, and this might be relevant. For someone like me (just a grateful user of the graphics stack) this is just trivia, for somebody into debugging this it might be higly interesting.

Your Answer

