> I have no such menu, I have a ">>>" prompt and a blinking cursor,
That is the alternative console, called SRM, which is used to boot OSF/1
(Digital Unix). I think you'll find instructions for booting from SRM
as well as from ARC -- if you have a system with ARC as well, you should
be able to go to the ARC console by giving SRM the command 'arc'. This
works on the UDB/Multia, anyway.
~kzm