[Simh] Install VAX/VMS 4.4 on a simulated VAX-11/780

[Clem Cole]

below...

On Thu, Mar 29, 2018 at 7:51 AM, Henk van de Kamer <simh at vandekamer.com>
wrote:

> Clem Cole schreef op 25-3-2018 om 23:23:
>
>> A small suggestion...   while you can probably get the 780 to recognize
>>> and support a TU58, booting from it may be difficult (I did not find it
>>> mentioned in any SDP or other doc).
>>>
>>
> In another post I gave a link which suggested that it could be present.


​Yeah, Mark has it in the simh configuration.  But be careful, there are
lots of the things you can do with the simulator that was never done in
real life.   Also there may be 'latent' support in the OS for some things.
For instance, Tru64 will boot and operate just fine with an Adaptec SCSI
controller ​in it.   That actually the configuration I ran in my office at
DEC, but it is not official in the 'Software Product Description' (*a.k.a.*
SPD)  because it will screw up (in that case an Adaptec can not support
fail-over so it was only officially support on Alpha/NT systems - but we
ran engineering systems with them all the time).

So you need to check the SPD for the specific release.  That will tell you
what DEC tested and supported in the field.  Anything else, you are in the
ocean without a life preserver -- you can swim and you might be safe, but
don't bank on it either.



>
>
> The 780 family has a dedicated PDP-11 with RX floppy drives that runs as
>>> the 'front end' for it and boots it. The PDP-11 run an small OS RSX-11/S (I
>>> think - but man those bit in my brain are long
>>> lost) and can reach in the SMI to load the OS image into memory
>>> from the disk and then points the system at it.
>>>
>>
> I searched what the TU58 exactly was and found [1]. They say it could be
> used to bootstrap the RT-11 [2] operating system on a PDP-11. That seems
> to be the one :-)

​Could be - as I said, those bits in my brain have long ago rotted.   The
780 and the KL10 both had a PDP-11 spliced into them to boot them up as a
front end.   The system console (which was typically a DECwritter-II) is
connect to a DL-11 on the PDP-11.   When typing to something on the main
computer the local OS on the front-end reads the uart on the DL-11 and
passes the characters to/from the host.    I thought I remembered that it
was a modified RSX-11 called RSX-11S that ran on the front-end, but I could
be confusing with another application.

The key point for you is that the 780 when it turns on is a bunch of hot
rocks.   It needs to have its microcode loaded before it can do anything,
as its microcode is stored in ram, not rom.  The system microcode lives on
the floppy disk in the front-end​.   Once the microcode is loaded, a vax
bootstrap can begin.

As a cost reduction on the 750, Dave Cane (HW design lead) developed it
without PDP-11 front-end (which was probably a marketing requirement).
 I've forgotten the complete sequence, since the 750 also had microstore.
IIRC: the front panel on the 750 (and the 11/34 and few other systems) is
an microprocessor.   The 11/34 used a i8008.   I think the 750 its was an
i8085, but I do not remember.   I think one thing is does is load the
microcode, but that's stored in the micro's rom's not on a floppy like the
780 and KL10.  But the microcode might be in ROM, I just don't remember
(I'll ask Dave if he does next time I see him).

The TU58 and the DECwriter might actually be directly connected to the
microprocessor, but again I've forgotten the details (look at the prints),
but there is some way they are available to the Vax directly, which is a
difference than the 780.

The point being that the TU58 driver in the host OS has to know how to
interface to the device.  Again IIRC, the HW design of the the TU58, as you
noted is an RS-232C serial device (basically predated the current USB idea
by about 25-30 years).


> In another post the same was suggested. However I only found three TU58
> tape files with the standalone backup 4.0.

However, I bet they that was only tested on a 750 and only on specific
configs as defined in the SPD.

The trick if you are really trying to be period relevant is get a copy of
the SPD and make sure vax750.ini file you create is actually one that
defines hardware that was tested and released for that version of the OS.

Anything else, might work, but you could be running into a number of ways
that things are almost but not quite.

If you can find something like Will Senn's Installing and Using Research
Unix Version 7 In the SimH PDP-11/45 and 11/70
<https://drive.google.com/file/d/0B1_Jn6Hlzym-Zmx1TjR3TENDQTA/view> for VMS
and the 750 and 780, I think you'll find like Will did, that he needed to
have a tape.ini file (which is on page 4 of his document) that was exactly
what Ken and Dennis described in their release.   The same will be true for
the Vax and VMS.

FWIW: If you are asking questions, please list as Will does, the foo.ini
files you are using at each step when you ask more questions.   Make it
clear exactly how you have configured things - I personally have not been
able to easily parse some of your messages.

If the bits you are using are not somehow corrupted, the system needs to be
configured as VMS expected it with only the HW devices and versions/models
of those devices that were supported by VMS at that time.

Best wishes
ᐧ
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