Peter, I answered my own question. The VAX/VMS Version 1.6 SPD (http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/AE-C770D-TE%20VAX-VMS%20Operating%20System,%20Version%201.6%20SPD%2025.1.4.pdf) specifically states Mixed-MASSBUS configurations were supported:
NOTE: MASSBUS disk drives and magnetic tape transports can be attached to the same MASSBUS. Your predicament remains a mystery. Larry Baker US Geological Survey 650-329-5608 ba...@usgs.gov > On 7 Nov 2017, at 3:57:13 PM, Larry Baker <ba...@usgs.gov> wrote: > > Peter, > > My reading of your hardware setup sounds like what was called a > "Mixed-MASSBUS" configuration, that is, mixing disks and tapes on the same > MASSBUS. PDP-11 RSX-11M-Plus supported Mixed-MASSBUS. We dual-ported all > our disks and used the MASSBUS that came with our tape drives that way. I > think Mixed-MASSBUS support was unusual. I do not remember if VMS 3.0 > supported Mixed-MASSBUS. If not, what you are seeing might be the result. > > Larry Baker > US Geological Survey > 650-329-5608 > ba...@usgs.gov <mailto:ba...@usgs.gov> > > > >> On 7 Nov 2017, at 12:54:40 PM, simh-requ...@trailing-edge.com >> <mailto:simh-requ...@trailing-edge.com> wrote: >> >> ------------------------------ >> >> Message: 4 >> Date: Tue, 7 Nov 2017 20:54:31 +0000 >> From: Peter Allan <petermal...@gmail.com <mailto:petermal...@gmail.com>> >> To: "simh@trailing-edge.com <mailto:simh@trailing-edge.com>" >> <simh@trailing-edge.com <mailto:simh@trailing-edge.com>> >> Subject: Re: [Simh] Simh Digest, Vol 166, Issue 12 >> Message-ID: >> <cajcrz55fv2ube5phmtbouxl5yzt8cpyiyhn1cygxghzhbxe...@mail.gmail.com >> <mailto:cajcrz55fv2ube5phmtbouxl5yzt8cpyiyhn1cygxghzhbxe...@mail.gmail.com>> >> Content-Type: text/plain; charset="utf-8" >> >> In order to try to understand why I am having trouble reading a simulated >> tape with a simulated TE16 tape drive on a simh VAX 780, I have tried >> several configurations. >> >> >> Firstly, a point of clarification. The problem that I came across was in >> finishing the installation of VMS 3.0. This was necessary in order to be >> able to install VMS 1.5 using DSC2, but I have no problem with the >> installation of VMS 1.5 itself. VMS 1.5 is a red herring - the problem is >> with VMS 3.0. >> >> >> I had configured a VAX 780 in simh with three RP06 disk drives and two TE16 >> tape drives. I was using TE16 tape drives rather than TS11 really just >> because when I was the system manager of a real 780, it had two TE16 tape >> drives. >> >> >> All of this has been done on a host system running CentOS 5 (for simh >> 3.8-1) and CentOS 6 (for simh 4.0). >> >> >> To remind you of the problem, I started the installation of VMS 3.0 by >> booting stand-alone backup and restoring a saveset from a tape that I >> downloaded from the University of Stuttgart. The first phase went fine and >> when I rebooted the 780, the system asked which device contained the >> installation media so that it could automatically complete the installation >> of VMS. I entered MTA0: and this is where things went wrong. Wilm suggested >> I should trying using a TS11 drive (MSA0) rather than a TE16 drive and this >> did indeed work, but this left me wondering why? >> >> >> I have tried to restore a BACKUP saveset from a tape to a disk using >> several configurations. I have tried: >> >> - Two difference versions of simh, 3.8-1 and 4.0 >> >> - Three different versions of VMS, 3.0, 4.6 and 7.3 >> >> - Different simulated tapes >> >> - The two different simulated tape drives, TS11 and TE16 >> >> The results have surprised me. >> >> 1) Changing the version of simh makes no difference to the results. >> >> 2) I only get a problem in restoring a saveset from tape when running >> VMS 3.0 as the operating system. Everything works fine with VMS 4.6 and 7.3. >> >> 3) I have tried different tapes, but if the system is going to fail to >> do a restore operation, it does it with all of the tapes containing BACKUP >> savesets that I tried. >> >> Following a suggestion from Kevin Handy, I tried to copy the savesets from >> tape to disk, but the copy failed on the VMS 3.0 system when using a TE16 >> tape drive. >> >> >> My experiments indicate that there is a problem with VMS 3.0 when using >> TE16 tape drives. However, this seems so unlikely, not least because the >> sequence of operations that I have gone through is what hundreds (thousands >> probably) of system managers must have done to install VMS 3.0 on real >> hardware, including my predecessor with “my own” 780. >> >> >> This leaves me stumped, but at least I have narrowed the problem down and I >> am able to do the installation of VMS 3.0 (which lets me do the >> installation of 1.5) by using a TS11 drive. >> >> >> The only thing I can think of is to wonder if the way that VMS handled TE16 >> (i.e. massbus) tape drives changed between VMS 3 and VMS 4 and that somehow >> there is a bug in simh that only rears its head on the earlier version. I >> confess this is a stab in the dark. >> >> >> Anyone got a bright idea about this? >> >> >> >> Cheers >> >> >> Peter Allan >> >> >> >
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