VAX/VMS archiving and replacement

Seth J. Morabito sethm at
Thu Nov 16 16:35:16 CST 2006

Hi Joe,

On Thu, Nov 16, 2006 at 04:37:02PM -0500, joe heck wrote:
> Now for part two.  If I really want to get rid of my MicroVax 3100 and 
> run a simulator, can I really have a stable system with something like SIMH?

With caveats.

First, simh is undergoing some overhaul right now while Bob Supnik adds
idle loop detection  to the code.  This will eventually result in SIMH
being *much* less resource intensive, and from what I've read he intends
to have it in the next release of the software, sometime soon-ish.  But
as it is right now, today, running SIMH eats up 100% of your CPU while
it's running.

Second, SIMH simulates a MicroVAX 3900 with an RQDX3 controller, not a
SCSI controller, so I'm not sure that just imaging your drives will
work.  It might!  But it may also confuse things if your drive images
end up being larger than RA92 drives.  I've never tried it.

> The needs are modest: All of my printers and terminals are off 
> Decnet/LAT, and I can put the two modems over there as well and take 
> them off the serial ports.  I can probably also figure out a way to make 
> backups, probably by backing up the system disk image on the PC.  I 
> think I would use XP.  In reading the SIMH documents it seems like a 
> second ethernet card is necesary, but that seems reasonable.  However, 
> can I run something older like VMS 5.5-2?

You can run anything supported by the MicroVAX 3900.  I used to run VMS
5.5-2 on mine all the time, so I suspect it would work just fine!


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