[Techtalk] updatedb hard drive thrashing

[ed orphan]

I'm running Red Hat 7.3 and every so often,
while I have KDE going, the hard drive starts
to work very very hard. It sounds like it's thrashing.
So I got into root and ran top. The problem seems
to be a program called   updatedb.
It was gobbling up CPU time and working the
hard drive very hard.
Is updatedb an important program? Can I axe it?
What does it do?
Even when I close down KDE, and exit the user
account, and I'm just in root on the command line,
it keeps going. I have to do a shutdown and re-boot
to make it stop thrashing the hard drive.
Does anyone else have this problem?
Any information on  updatedb would be most welcome!