VAXstation 3100/76 SCSI disk over 1GB

[Allison]

>
>Subject: RE: VAXstation 3100/76 SCSI disk over 1GB
>   From: "Antonio Carlini" <a.carlini at ntlworld.com>
>   Date: Fri, 22 Apr 2005 19:20:00 +0100
>     To: "'General Discussion: On-Topic and Off-Topic Posts'"	<cctalk at classiccmp.org>
>The console disk driver is used early on in the boot process
>(until enough of OpenVMS has been loaded that it can switch
>to its own full-featured driver) and also during crash dumping
>(since the console driver is in eprom, it can be relied on not
>have become corrupt).
>
>If any of the files needed during boot end up past the 1.073GB
>mark, the system will not boot. Event if the files happen to lie
>in accessible places initially, they might be moved by a
>subsequent upgrade or disk defragmentation.
>
>Much, much worse is the behaviour during a crash. If the 
>crashdump file happens to be beyond the 1.073GB mark, then
>anything actually at the wrapped around address is at risk!
>
>There are ways around this problem, but the only easy one
>is to use an RZ26 (1GB disk) as the system disk. That's
>not a problem at least for releases up until OpenVMS V7.1.
>I stopped getting updates at that point so I don't know
>how much bigger VAX releases have become.
>
>The problem is not such an issue with *BSD since you can
>effectively control what lives where.
>
>The issue affects all VAXstation 3100s, the 
>MicroVAX 3100 Models 10 and 20 and the early releases
>of the MicroVAX 3100 Models 10e and 20e. I believe that
>a fix was produced for the 10e and 20e and ROMs dated
>after April 1992 are fine. The OpenVMS FAQ has more details.
>
>So just because it seems to work, does not make it a good idea :-)
>

I affirm that having tried it.  I also have two M76s and both will
boot larger but only one has the factory console rom fix.

My solution was simple, use a 1gb disk for the system disk, second 
drive is a nice 2.7gb and that works fine even with 5.4-4h.  It's 
a cheap solution as 1g SCSI drives were easy to find for a while
for free.  I've found for a system disk 1gb is plenty even for 7.2
and likely later as I can put the page/swap files on the second 
drive along with user data/files.


Allison