boot.iso 

        Network install cd iso image,  Use it when you want to install
        over the network

SL.Fermi.305.091305.i386.disc1.iso  
SL.Fermi.305.091305.i386.disc2.iso  
SL.Fermi.305.091305.i386.disc3.iso
SL.Fermi.305.091305.i386.disc4.iso

        These are the cdrom images for a full cdrom only install.
 
SL.Fermi.305.091305.i386.md5sum

	This file contains the md5 checksums for the above images.  Use
	md5sum <file> to get checksum and compare with expected value in
        .md5sum file.

You do NOT need to burn both boot.iso and the SL.Fermi.*.i386.disc*.iso
images.