What is this rawhide thing?

[Robert Firth]

Hi!

I am trying to install FC4 from dvd onto a Dell PowerEdge SC420.  The 
graphical installation fails, which I think is explained by Bugzilla 
#161242, which admits to a problem with x11 and vesa adapters.  This 
talks about a fix having been imported to rawhide - but what is this 
rawhide thing?  Does it provide an updated dvd iso image for FC4?  Bear 
in mind that I don't have a system installed as yet, so an updated 
xorg-x11 rpm is no use to me, nor can I use yum or up2date. 
Unfortunately I need to use the graphical installation because I am 
trying to install to a pair of sata disks configured with software 
raid-1, and the text version of disk druid doesn't seem to support this.

Any suggestions gratefully received.