[Simh] VMS 4.6 won't boot from a Massbus disk

[Wilm Boerhout]

Peter Allan mentioned  on 29-1-2011 15:01:
> Brian, thanks for your advise. Changing the value of RTIME has indeed 
> got VMS 4.6 to boot on my emulated VAX 780, which is terrific.
>
> I started by setting RTIME to 1000, as suggested and I decreased the 
> value until the system no longer booted. The smallest value I could 
> use was 26.
>
> The system now boots very quickly and there is only about 1 second 
> between the message
>
>    VAX/VMS Version V4.6  6-Jul-1987 17:00
>
> appearing and the boot sequence finishing. In fact, I could detect no 
> difference between the speed of the emulated system whether I set 
> RTIME to 26 or to 1000, although all I am doing at present is booting 
> the system and typing a few simple commands like SHO DEV D.
>
> I realised this is a lot faster than booting from an RA81, which has 
> always worked, but takes about 10 seconds from the above message 
> appearing to completing the boot process. Both systems are clean 
> installs with nothing in the startup .COM files yet.
>
> My current configuration is:
>    One RP06 disk containing VMS 4.6
>    One RA81 containing VMS 4.6
>    One RD53 containing stand alone backup 4.6.
>
> I discovered that when I boot from the RP06 system disk, the MSCP 
> disks are not recognised and are not available after the system has 
> booted.
>
> Right now, I am not to bothered about the MSCP disks not being 
> recognised if the system disk is a Massbus one, but I bet I will be at 
> some time in the future. I tried changing the RQ disk parameters 
> ITIME, QTIME and XTIME, but
> the little playing that I did did not result in the MSCP disks 
> appearing after the system booted.
>
> Anyone got any bright ideas about this problem?
>
> Peter Allan

I do not have a V4.6 system at hand, but consider this general 
principle: if you boot VMS from a cloned or freshly installed system 
disk, it is beneficial to run AUTOGEN, after checking MODPARAMS.DAT for 
anomalies. Could it be that when booting from a MASSBUS device, the MSCP 
driver is not automatically loaded? Not sure if V4.6 supports this, but 
try setting MSCP_LOAD=1 in MODPARAMS.DAT, and AUTOGEN the system. Later 
versions of VMS have the SYSGEN command SHOW MSCP_LOAD, SHOW 
MSCP_SERVE_ALL, not sure if V4.6 has this.

It may also take some time for the CONFIGURE process to enumerate all 
disks. Is the configure process started at all when booting from 
MASSBUS? Otherwise, @SYS$SYSTEM:STARTUP CONFIGURE will do so.

/Wilm