[Simh] Standalone boot on vax8600?

[Mark Pizzolato - Info Comm]

On Jul 10, 2014 2:02 PM, Johnny Billquist <bqt at softjar.se> wrote:
>
> On 2014-07-11 01:08, Mark Pizzolato - Info Comm wrote:
> > On Thursday, July 10, 2014 at 3:13 PM, Cory Smelosky wrote:
> >> On Thu, 10 Jul 2014, Henry Bent wrote:
> >>
> >>> Well, that at least did something different.
> >>>
> >>> sim> boot rq0 /r5:8
> >>> Loading boot code from vmb.exe
> >>> %BOOT-F-Unexpected Exceptio
> >>>
> >>> The 8600 simulator always seems to cut off the last character of its
> >>> messages, I wonder if that's in any way related to the other console
> >>> problems.
> >>>
> >>
> >> 780, 750, and 730 have the same issue...along with not actually booting from
> >> the console RL, floppy, et al.
> >
> > The last character output in a message just prior to executing a HALT instruction is not surprising since the simulator implements a delay (as a number of instructions executed) from when the data is put in the output register prior to generating the completion interrupt/status.  The halt instruction gets executed before the delay number of instructions have completed.  Even if that was 'fixed', nothing operational would change.  The reason the message has been generated will still exist.
> >
> > As for direct support for booting an OS from the console media, the 8600 supports BOOT CS /R5:xx to boot from the console RL02.  Other than that, VMB.EXE is actually performing the boot operation and I think that when I checked VMB didn't know how to boot from console floppies on a 780, but it can boot from the console TU58 on both the 730 and 750 (BOOT TD /R5:xx).
>
> Well, I used to boot NetBSD on "my" 8650 by direct booting without VMB,
> Here is the COM file:
>
> ------------
> !
> ! Load 'boot.' and boot NetBSD.
> !
> ! 'ra' MSCP drive type boot to multi user mode
> !
> !
> SET SNAP ON             ! Enable ERROR_HALT snapshots
> SET FBOX OFF            ! System will turn on Fbox
> INIT                    ! SRM processor init
> UNJAM                   ! UNJAM SBIA's and enable master sbia interrupts
> INIT/PAMM               ! INIT physical address memory map
> DEPOSIT CSWP 8          ! Turn off the cache - System will enable cache
>
> !DEPOSIT R10 9          ! 'ra' MSCP drive type - uba0 - drive 0
> !DEPOSIT R11 0          ! Software boot flags (multi user mode)
>
> DEP R0 11
> DEP R1 20006000
> DEP R2 2013f468
> DEP R3 F                ! Unit number
> DEP R4 0
>
> LOAD/START:0 BOOT.      ! Load 'boot.' at memory location 0
> START 60                ! Start 'boot.' at the address 60
> ------------
>
> But note, that is not not through VMB, so any discussions about R5
> previously is not relevant here. Also, the start address is very much
> depending on the actual image loaded.

All of these things can still be done with the simh VAX simulators.  The default BOOT command operations setup and use VMB since that was the most common operation across 'most' deployed systems.  What is done within the BOOT command is very much what Johnny's COM file does (init register values as need, load and start VMB).

- Mark
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