TV computers - Tektronics 4051/4052 and 4081 memories

From: Rick Bensene <>
Date: Mon Feb 7 14:45:03 2005

It's either a 4051 or a 4052 -- the two machines were virtually identical
from the exterior, but
inside they were quite different, with the 4051 using a Motorola 6800
microprocessor, and the 4052
using a bit-slice emulation of the 6800 that ran a lot faster than the 4051.

An interesting note about the old Battlestar Galactica. They also used
Tektronix 4081's.
The 4081's weren't actually used on the set, IIRC, but were used for close
up screen
shots of battle situations where the write-thru mode of the 4081, with it's
processor being better at rendering animated vector graphics than that
"etch-a-sketch" type
graphics of the 4051/4052.

It was a graphics design station built on an OEM Perkin Elmer (formerly
Interdata) 7/16 CPU board (an
architectural and instruction set clone of an IBM 360), in a custom
backplane about the size of a file
cabinet. Tek-made memory, I/O, and graphics interfaces filled out the card
cage. The bus, as I recall,
was asynchronous, requiring all kinds of handshaking between the boards for
across-the-bus communications.
We had a hardware engineer in the CAD group at Tek that designed a RAMDisk
(using, as I remember, 4164 DRAMs)
for the machine, and had a heck of a time with all of the async bus logic.

It was all mounted in a nice desk-sized unit, with available Wangtek disk
cartridge drives, and a
standard cartridge tape drive (ala the 4051) that contained the boot image.
There was a "IPL" button on the
machine's panel that when pressed, would load the operating kernel (called
GECOS, as I recall) off of the tape for diskless
systems. The system used a 19" DVST (Direct-View Storage Tube) for display,
that had write and
write-thru modes. The system used a custom display-list processor, that
allowed the CPU to simply
load up an area of memory with a display list of vectors, and the display
list processor would
take care of all the rest. Graphics input was typically with an OEM'd
Summagraphics graphics tablet.
I believe the machines were circa '77/'78 or so, but not sure.

Wonder if there are any of these machines left surviving? I wrote a lot of
code in the Macro Assembler
for this beast when I worked at Tektronix in the Computer Aided Design group
in the late '70's. There was an effort
to develop an internal schematic capture package on the 4081 that would
allow logic schematics to be
drawn up on the machine, and from there, a netlist generated that would be
usable for input into
a circuit board routing program (also developed internally).

Rick Bensene


> -----Original Message-----
> From:
> [] On Behalf Of Mike
> Sent: Monday, February 07, 2005 11:23 AM
> To:
> Subject: TV computers
> Does anyone recognize this computer
> Is it the Tektronix 4051 Graphics system mentioned in an
> earlier post?
> --
> Collector of vintage computers
> Machines to trade
> Open Source Weekend
Received on Mon Feb 07 2005 - 14:45:03 GMT

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