9.0 install problems

[Henry Olyer]

When I boot the CD I get a different menu, ie., boot, shell, install.

Since the CD is in the CD-ROM drawer and I know how to use sysinstall (or
so I thought!,) I get a fresh shell and say "sysinstall".

Okay?

Except I can't write the disk.  Notice, I have not explicitly mounted it or
done anything to reserve it.

I need a procedure to do this please.

It's just a small machine.  But having this up let's me do a backup and
once I've backed up the disks on my other computers, then I can do some
serious stuff with 9.0.

I'd like to use sysinstall, if possible.  I know it and I like it.  I do
have some other FBSD boxes nearby, each with TCP/IP running fine;  But I'm
not knowledgeable with PXE.