Re: anyone know what's going on in dw780_errchk

[Johnny Billquist <bqt%softjar.se@localhost>]

Brad Parker wrote:
> Johnny Billquist wrote:
> > Not sure how much we care, but VMB have reserved meanings for R0-R5, 
> > which we would break by this idea.
>
> I was afraid of that.  Is that documented somewhere?
>
> meanwhile, I discovered that "boot ra(3,0,0,1)netbsd -a" does what
> I want, which is to ask for the root device.
>
> I'm closer to a recipe for installing from tape.

Here is what the boot files on the 8650 machine here says:

.type defBOO.COM
!
! Version: 001.000
!
!       DU0 BOOT COMMAND FILE - DU0BOO.COM
!
!       This UNIBUS disk boot command file is set up to boot from a RA
!       series disk connected to a UDA50.
!
!       It assumes the DW780 is on SBIA #0, the TR level of the DW780
!       is set to 5, the UDA50 is the first one on the system, the
!       UDA50 CSR address is 772150 and the disk's unit number is 0.
!
!       If any of these assumptions are not true for your configuration,
!       you may still use this command file by entering the BOOT/NOSTART
!       console command and then altering the appropriate register values
!       when the console command prompt reappears. Use the console
!       command SHOW BOOT.HLP/ASCII to get more information on how to
!       use the BOOT/NOSTART command and R5 boot options.
!
!
! Operating System Disk:        UNIBUS DISK (UDA50)
!
!
SET SNAP ON             ! Enable ERROR_HALT snapshots
SET FBOX OFF            ! VMS will turn on Fbox
INIT                    ! SRM processor init
UNJAM                   ! UNJAM SBIAs, Enable Master SBI interrupts
DEPOSIT CSWP 8          ! Turn off the cache (VMS turns the cache on)
!
DEPOSIT R0 11           ! Device Type is UDA50
DEPOSIT R1 3            ! SBIA #0; TR of the DW780 is 3 (DW0)
DEPOSIT R2 0103F468     ! Controller A (01) at Unibus CSR address 772150
DEPOSIT R3 F            ! Unit number to boot from (in HEX)
DEPOSIT R4 0            ! Logical block number to boot from if R5 bit 3 
is set
                        ! Use R5 for optional boot control flags
DEPOSIT R5 10008        ! Boot to multiuser (bit 0 - ask for image)
                        !                   (bit 1 - single user)
FIND/MEMORY             ! Locate a 64KB chunk of good memory
EXAMINE SP              ! Display load address
LOAD/START:@ VMB        ! Load VMB 200 bytes above the start of the good 
block
START @                 ! Start VMB at the load address


I know that I have more documentation on R5 somewhere, but I can't 
remember offhand. Maybe someone else do?

Note that this is the command file I use to boot NetBSD. So it uses R4 
to tell which block to boot from. VMS don't use that feature. However, 
Ultrix also do.
I have an alternative way to boot as well, by loading in boot from the 
console pack, but I prefer doing it this way. :-)

        Johnny

--
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt%softjar.se@localhost             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol