Sunday, April 12, 2009

xserver crash on restart taught me optimised use of memory.

I have a machine which originally arrived with 128 MB RAM and Linux Distributions with 2.4 series kernels (Mandrakelinux 9.1) worked well with this memory. Even Ubuntu 5.04 with 2.6 series kernel worked vey well.

Subsequently I added 256 MB RAM to the machine making it 384 MB to use Ubuntu 6.06 Dapper Drake properly.

I soon learnt to use lightweight Window Managers to have good speed with later versions of Ubuntu and also tried Debian and Arch Linux to further optimise thye memory usage.

The video setting in the BIOS was on "Auto" and 72 MB RAM was getting allocated towards the video leaving 312 MB for the OS.

Although Ubuntu says that its Live CD works with 256 MB RAM it is very slow and even 312 MB is less for effective use.

Recently I downloaded Ubuntu 9.04 Beta Live CD and in order to use it effectively changed the video setting in the BIOS to minimum (8 MB). The memory available for the Live CD was 360 MB (instead of 312 MB) and it worked very well.

Subsequently I forgot to restore the BIOS setting and continued using Linuxes installed on the hard disk (Ubuntu Hardy, Archlinux and antiX). They were working very well till I decided to change the Window Manager on Ubuntu Hardy and logged out of GDM to change session. To my surprise, the xserver crashed. I checked restart of xserver on Archlinux and antiX and it crashed on those distributions as well.

I googled for "xserver crash on restart" and read many bug reports and tried some remedies. Ultimetly I discovered the BIOS video setting and changed it to "Auto" once again.

Then I remembered that I had tested "logout" on Ubuntu 9.04 Beta Live CD and xserver did not crash.

I changed the BIOS video seiing to 16 MB and found that Archlinux (with xserver 1.5) did not crash on restart but Ubuntu Hardy Heron (which has xserver 1.4) required 32 MB setting in the BIOS.

Today I upgraded to xserver 1.6.0 on Archlinux and it is not crashing on restart with minimum (8 MB) video setting in the BIOS (like Ubuntu 9.04 Beta). With this setting the available memory for the OS has jumped from 312 MB to 367 MB.