From: Tim Shoppa <shoppa@alph02.triumf.ca>
Message-Id: <9803181517.AA25259@alph02.triumf.ca>
Subject: Re: V7 startup
To: allisonp@world.std.com (Allison J Parent)
Date: Wed, 18 Mar 1998 07:17:18 -0800 (PST)
Cc: pups@minnie.cs.adfa.oz.au
In-Reply-To: <199803180459.AA20873@world.std.com> from "Allison J Parent" at Mar 17, 98 11:59:06 pm
Content-Type: text
Sender: owner-pups@minnie.cs.adfa.oz.au
Precedence: bulk

> That reminds me. Why can't the 11/73 boot the unix RL pack directly from
> console boot dialog?   The system boots RSTS and RT-11 packs.  Is the boot 
> block munged/missing?  I might add it boots fine using boot/foreign from 
> rt11.

The 11/73 firmware bootstrap expects the boot block to conform to certain
standards specified by DEC in the early/mid-80's.  In particular, the
bootstrap must begin with a NOP, but there are some other requirements
I don't recall at the moment.

The toggle-in bootstraps that DEC supplied didn't do any such checks (who'd
want to toggle tha check in everytime, anyway?), they just read block 0 to
location 0 and jump to it (well, some also assume things about the SP
going somewhere reasonable, and sometimes certain register locations set
to certain things.)  And RT-11's BOOT/FOR doesn't make any such checks,
either.

> It's a curiousity as having RT on floppy or HD is not a big thing for me.
> But if it can be fixed that would be an improvement.

You can either rewrite the 11/73 firmware to not do the check, or you can
rewrite the V7 boot block so it conforms to DEC's standard.  The RL02
is a particularly stupid device and requires an inordinately large bootstrap,
so there may not be a lot of free room in the V7 boot block.  You can also
stick a "toggle-in" RL02 bootstrap into RAM via ODT and execute that.  But
I've decded that for me, the solution of RT's BOOT/FOR is the best, just
as you seem to have :-).

Tim. (shoppa@triumf.ca)