[Simh] Booting the vax750 simulator.

[Mattis Lind]

Hello!

I am in the process to revive an VAX-11/750 machine but since I have no
tape (nor install tapes) drive my idea was to  create an image which I
could transfer to a SCSI disk and then use a MSCP SCSI controller to boot
the machine.

I thought it would be a good idea to use the SimH vax750 simulator to do
this work. But I encounter problem. Many of these problems are probably due
to the fact I am not very familiar with SimH. Although I think I read
though several documents and studied the source code.

The booting process of the SimH vax750 simulator seems to differ from the
real VAX-11/750. On the real thing when I insert console media and boot it
it will read and I get a BOOT58> prompt. This doesn't happen at all on the
simulator. Instead it seems that it preloads vmb.exe and then execute it.

The images I have been using was found on
http://iamvirtual.ca/VAX11/VAX-11-software.html

All tests below is run using SimH from github compiled on MACOS. Although I
have also tested to compile it on Linux with the same result.

This is what happen on the simulator:

sim> boot td0
Loading boot code from vmb.exe



Please remove the volume "CONSOLE" from the console device.

Insert the first standalone system volume and enter "YES" when ready: YES

Resuming load operation on volume "CONSOLE", please stand by . . .


1 BRK AT 00001C50
00001C50/CF00FB01

It seems some kind of command line is active since I get this output when I
press some random keys:


EH?
EEE
00000EEE /8AAF9552


--------

Booting a standalone backup works OK if I don't follow the instructions to
replace the console media the first time.


sim> attach td0 /Users/mattis_lind/Downloads/BE-CT97A-BE.TAP
TD: writing buffer to file
TD: buffering file in memory
sim> boot td0
Loading boot code from vmb.exe



Please remove the volume "SYSTEM_1" from the console device.

Insert the first standalone system volume and enter "YES" when ready: YES

Resuming load operation on volume "SYSTEM_1", please stand by . . .


Please remove the volume "SYSTEM_1" from the console device.

Insert the next standalone system volume and enter "YES" when ready:
Simulation stopped, PC: 000083D8 (MFPR #20,R0)
sim> attach td0 /Users/mattis_lind/Downloads/BE-CT98A-BE.TAP
TD: writing buffer to file
TD: buffering file in memory
sim> cont
YES

Resuming load operation on volume "SYSTEM_2", please stand by . . .



   VAX/VMS Version V4.0 15-SEP-1984 22:29


Please remove the volume "SYSTEM_2" from the console device.

Insert the standalone application volume and enter "YES" when ready:
Simulation stopped, PC: 80008B1F (BRB 80008B1F)
sim> attach td0 /Users/mattis_lind/Downloads/BE-CT99A-BE.TAP
TD: writing buffer to file
TD: buffering file in memory
sim> cont
YES

Resuming load operation on volume "BACKUP", please stand by . . .


%BACKUP-I-IDENT, Stand-alone BACKUP V4.0; the date is 17-JUN-1984
22:40:44.48
$

---------

Then trying to run various diagnostics images that are supposed to be
standalone and do read on the real thing but gives the following result:

sim> attach td0 /Users/mattis_lind/Downloads/BE-S198Q-DE.TAP
TD: writing buffer to file
TD: buffering file in memory
sim> boot td0
Loading boot code from vmb.exe



Please remove the volume "VMS Exchange" from the console device.

Insert the first standalone system volume and enter "YES" when ready: YES

Resuming load operation on volume "VMS Exchange", please stand by . . .

ECKAL -- VAX 11/750 Cache/TB Diagnostic
HALT instruction, PC: 00002608 (MTPR #F,#26)
sim> attach td0 /Users/mattis_lind/Downloads/BE-S199T-DE.TAP
TD: writing buffer to file
TD: buffering file in memory
sim> boot td0
Loading boot code from vmb.exe



Please remove the volume "VMS Exchange" from the console device.

Insert the first standalone system volume and enter "YES" when ready: YES

Resuming load operation on volume "VMS Exchange", please stand by . . .

%BOOT-F-Unable to locate BOOT file
HALT instruction, PC: 000004C7 (BLBS 549,4C6)
sim> attach td0 /Users/mattis_lind/Downloads/BE-S200I-DE.TAP
TD: writing buffer to file
TD: buffering file in memory
sim> boot td0
Loading boot code from vmb.exe



Please remove the volume "" from the console device.

Insert the first standalone system volume and enter "YES" when ready: YES

Resuming load operation on volume "", please stand by . . .

%BOOT-F-Unable to locate BOOT file
HALT instruction, PC: 000004C7 (BLBS 549,4C6)
sim>

As you can see the Cache/TB diagnostic do read in and seem to execute but
fails. The others doesn't even seems to boot correctly.  When tested on the
real hardware all these start (although the Cache/TB fail, alas not at the
same location)

Maybe the best idea is to dump out the real BOOT PROMs from the actual
machine an load those into memory and start those? I haven't been able to
test this since the machine 100 km away.


I did successfully boot a Ultrix-4.0 tap file from bitsavers in the vax
andra microvax2 simulator. But how can I do that on the vax750 simulator?
Doing "boot tq0" give "Command not allowed". Although help file indicate it
is a valid command!?

Any help appreciated!

/Mattis
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