>After a bit of mucking around I found that the microvax3100 
>just plain doesn't like booting off anything over a 1GB disk.
>
>Is this a well know issue?

Yes. All VAXstation 3100s and the MicroVAX 3100 10/20 have this issue.
So do the MicroVAX 3100 10e/20e unless the console is dated later
than April 1992.

Any other MicroVAX 3100 (e.g. M30/40/80/90 etc) is fine. All
the VAXstation 4000s are fine.

>Is accessing 'large' disks a problem or just booting from them?

The console boot drivers only know how to access the first
1.073GB, anything beyond that is wrapped around. For OpenVMS
these drivers are used not only for booting but also during
a crash to write out the dump. The former is an inconvenience
that results in a failed boot. The latter results in disk 
corruption.

NetBSD is a little different in that you can arrange for
all the critical stuff to lie in the first 1GB and so
avoid the problem altogether.

Antonio

 --  

Antonio carlini
arcarlini@iee.org