xeagle's Blog

HOWTO run Ubuntu on low RAM computers
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Ubuntu requires 256MB RAM to perform happily out of the box. It will run with 128MB of RAM, but with continuous swapping of memory to disk. If you have less than 256MB of RAM you can significantly improve Ubuntu performance by doing the following, in order of importance:

1) use a different window manager. Metacity (the default) is very memory intensive. Try icewm or fluxbox instead. To do that first ensure you have "universe" sources enabled and then "apt-get install fluxbox icewm". When you next login at the login screen click the Session button and choose either icewm or fluxbox as your default window manager.

2) remove unnecessary services. By default Ubuntu loads quite a number of services, assuming you will be using it like a server. I would hesitate to guess that 90% of Ubuntu users would rarely, if ever use such services. They all consume RAM. The easiest way to do this is to install "Boot-up Manager": "apt-get install bum". The run "bum" and unclick the following services: rsync, atd, apmd, acpi-support, dbus-1, mdadm, fetchmail, postfix - but first read what these services do and decide if you really need them. They can be rebooted if removing them break anything on your system. Others listed can also be removed in some circumstances. You will need to do a bit of research beforehand.

3) use low-RAM-requirement applications. Here are some suggestions:
browser: dillo or opera or lynx
email: sylpheed or mutt or pine
word processing: abiword
newsgroups: pan or slrn
file manager: mc
editor: vim
terminal: aterm or rxvt
pdf reader: xpdf
programming IDE: motor

4) remove gdm (the Gnome display manager) using bum. This consumes significant RAM. Before doing this choose the window manager you are happy with, make it your default and then next time you boot up you will login in a text mode terminal and then type "startx".

5) remove unnecessary virtual terminals. By default Ubuntu provides you with 6 virtual terminals. These are the login terminals you can get to by typing Ctrl-Alt-F2, Ctrl-Alt-F3 etc. Normally you only need one spare terminal in case of emergencies. To disable the others and free up even more RAM "gedit /etc/inittab" and comment out the lines below as shown:

#3:23:respawn:/sbin/getty 38400 tty3
#4:23:respawn:/sbin/getty 38400 tty4
#5:23:respawn:/sbin/getty 38400 tty5
#6:23:respawn:/sbin/getty 38400 tty6

6) be continuously aware of all running processes and the RAM that your applications are consuming. You can see the processes with "ps aux". Check out the RSS column which is the total memory consumed by a process. You can also check your memory situation with "free". The important value is the second row number under the free column. This is the total available free memory including memory which has cached applications.

7) free up video RAM (especially for those using onboard video chips which share memory). Edit the etc/X11/xorg.conf file and comment out the following lines:
# Load "record"
# Load "dbe"
# Load "dri"
# Load "glx"
# Load "xtrap"
# Load "type1"

The most important module you're not loading is dri which is for graphics acceleration. You will need to test this; it might not work with all graphics cards and will break graphics intense apps.

8) if you have 128MB of RAM or less Ubuntu is the wrong Linux distro for you (IMHO). I can highly recommend VectorLinux (http://www.vectorlinux.com). This is an incredibly fast Linux distro which can run with 64MB of RAM - and using the tweaks above can be made to run with just 32MB of RAM!