RescueCD - what is this for?

[Timothy Murphy]

I ran into a serious problem on my desktop
(I gave the command authconfig.gtk with openldap checked
which had the effect of stopping the machine booting)
so I burned a Fedora-7 rescueCD and tried that,
but it seems I was then supposed to insert the system DVD.

Actually, this machine didn't have a DVD reader, so that was out.
But it left me wondering what the purpose of the Rescue CD is?

I had assumed it was a Knoppix-like CD, but it appears I was mistaken?
I would have thought if I had the Fedora DVD, and could read it,
I could just enter rescue mode with that?

[I solved my problem by using a Knoppix CD, and deleting all mention
of ldap in /etc/nsswitch.conf .
I'm amazed that one word in that file can stop Fedora booting.]