Looking for a small fast VAX development machine

Jerome H. Fine jhfinedp3k at compsys.to
Sun Feb 21 14:12:41 CST 2016

 >Holm Tiffe wrote:

>>Ben Sinclair wrote:
>>I was just looking up VAXstations the other day on eBay. I checked
>>again now for 4000's, and the prices seem crazy. Is there something
>>particularly special about them, or is it just the usual eBay
>..that are the smallest and fastest VAXen so it is not so unlikely
>that the prices are crazy...
>Why you don't use an simulator (E11, simh) for the job?
That sounds like a good idea to use SimH for the VAXstation.  However,
I suspect that E11 (Ersatz-11) would be a bit difficult to use to emulate a
VAXstation since E11 is exclusively for the PDP-11.

As for the individual who mentioned the speed of an emulator, I have used
both SimH and Ersatz-11 on a 750 MHz Pentium III.  SimH probably runs
at about the speed of a PDP-11/93, probably even faster.  However, Ersatz-11
runs 15 times as fast for CPU speed and about 100 times as fast for hard 
disk I/O.
On a 2.83 GHz Q9550, Ersatz-11 ran about 100 times the speed of a PDP-11/93
for the CPU and hard disk I/O was probably about 200 times as fast. As just
one example, on a real DEC PDP-11/93 with ESDI hard drives, it took about
4 minutes to copy about 32 MB from one physical hard drive to a different
physical hard drive.  On the Q9550, it took less than 1 second.  I was using
RT-11 in all cases.  I would assume that an I7 CPU would be somewhat faster,
but maybe someone else has some benchmarks.

Jerome Fine

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