What are these services?

Hi,

I am kind of new to linx and would like to know more information about the following services that I see from top:

2 root -2 0 0 0 0 SW 0.0 0.0 0:00 keventd

3 root 18 19 0 0 0 SWN 0.0 0.0 0:00 ksoftirqd_CPU0

4 root -2 0 0 0 0 SW 0.0 0.0 0:00 kswapd

5 root -2 0 0 0 0 SW 0.0 0.0 0:00 bdflush

6 root -2 0 0 0 0 SW 0.0 0.0 0:00 kupdated

7 root -2 0 0 0 0 SW 0.0 0.0 0:00 jfsIO

8 root -2 0 0 0 0 SW 0.0 0.0 0:00 jfsCommit

9 root -2 0 0 0 0 SW 0.0 0.0 0:00 jfsSync

10 root -22 -20 0 0 0 SW< 0.0 0.0 0:00 mdrecoveryd

11 root -2 0 0 0 0 SW 0.0 0.0 0:00 kjournald

I have the Debian install. I would like to know what exactly are each of them and is it possible for me to disable some of them?

Thanks for your help.

Kevin