Message-ID: <Wta+ZIAyOWi2EwQ$@falstaf.demon.co.uk>
Date: Tue, 29 Dec 1998 23:20:18 +0000
To: "Steven M. Schultz" <sms@moe.2bsd.com>
Cc: pups@minnie.cs.adfa.oz.au
From: Robin Birch <robin@falstaf.demon.co.uk>
Subject: Re: Bob Supnik's Emulator.
In-Reply-To: <199812292303.PAA12398@moe.2bsd.com>
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Sender: owner-pups@minnie.cs.adfa.edu.au
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In message <199812292303.PAA12398@moe.2bsd.com>, Steven M. Schultz
<sms@moe.2bsd.com> writes
>Robin -
>       I don't think that's the case - but read on and see if my new
>       theory sounds plausible...
>
I think that I've independantly come up with the same answer but by a
different logical root.
>> Using separate bootstraps, boot and <program>, I have labeled and mkfs
>> an RP04.  I then tried restor.  Well, I can get restor to load and run
>> but it doesn't want to understand the dump file written with dd that is
>> created as part of the generation of a distribution set on the 11/73.
>
>       Umm, you can't use a 'dd'd image - you have to use 'makesimtape'
>       (or a similar utility) to add the record/file/bytecount markers that
>       the simulator expects to see.
>
Now this is what I didn't realise at first.  All I thought makesimtape
was doing was packaging up the files, not writing some structure around
them.

>> I suspect that there is some form of data conversion that I have to go
>> through before I can read the files on the emulator.
>
>       Yes, there is.  Not sure why it didn't occur to me earlier when you
>       mentioned having problems.
>
>       I assume you compiled and ran 'makesimtape' on the same system
>       (Sparc) as the simulator is running.
>
This is the big one, no.  I had assumed that as the simulator was
emulating a PDP that it would accept files generated to look like boot
files etc built on a pdp so I'm running makesimtape in the standalone
direcctory of the 11/73.  Nieve maybe but at least it was logical :-).

>       If so then it sounds to be like there's an endianness bug in
>       makesimtape.  That wouldn't surprise me since all I have are 
>       either little or pdp-11 endian systems and never tested makesimtape
>       on a big endian machine.
>
What I'll do is build makesimtape on the sun and see what happens then.

>       There are ifdefs around what I thought were the appropriate places
>       for flipping bytes - what you'll need to do is get Bob's description
>       of the simulated tape format (fairly simply and it's in the docs
>       somewhere as I recall) and the makesimtape.c source and see where I
>       "oops"d.
Back in a mo.

Robin
____________________________________________________________________
Robin Birch     robin@falstaf.demon.co.uk

M1ASU/2E0ARJ    Old computers and radios always welcome