Vt 103 / lsi 11/23 marketed as a desktop late 1980

Jerome H. Fine jhfinedp3k at compsys.to
Thu Apr 21 20:41:08 CDT 2016

 >william degnan wrote:

>Prior to the DEC Rainbow, Chrislin Industries was marketing the 11/23 with
>vt103 as a  desktop computer.  This is a 3rd party vendor.  Maybe they were
>on to something...
Back around 1988, one of my customers had a few VT103
systems with just an RX02 for storage.  A 3rd party
controller for an MFM drive (ST506 or DEC RD51) was
added since the DEC RQDX1 took too much power.  There
was still sufficient power and room to place the
ST506 drive inside at the base of the VT103.

Prior to that point, I had a VT103 with just 256 KB
of memory and a DSD 880/8 which had an 8 GB hard
drive / RX03 floppy drive in an external box.  So
there were other 3rd party solutions as well.

At one point, just to say that I had done so, I placed
a quad PDP-11/73 CPU along with 4 MB of memory, an ESDI
controller and a DHV11 with 8 serial ports into the
backplane of a VT103.  I had to power the three 600 MG
hard drives from an additional PC power supply since
there was insufficient power from the VT103.  But that
demonstrated that just a 4 x 4 Qbus backplane was
sufficient to run an extremely powerful PDP-11 system
using the VT103 as a base system with its own console
terminal.  At one point, I heard that someone even
managed to make the first two slots ABCD which allowed
a MicroVAX II to be used instead, although a PDP-11/83
with PMI memory would have also been possible or a
PDP-11/93 could also have been used and one quad slot
would still have been available without the ABCD change
to the backplane.

These combinations could have been produced by DEC
and been years and technology ahead of the PC computer,
but that never happened.  I have the impression that
the VAX was placed in a position of priority and most
development on the PDP-11 side which could compete with
the 32-bit VAX was restricted even though there were
still many applications where a 16-bit system was more
than adequate.  DEC could have sold millions of VT103

Jerome Fine

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