[pdp7-unix] card readers (was ald)

Phil Budne phil at ultimate.com
Tue Oct 22 12:59:14 AEST 2019

Bob Supnik wrote:
> It's probably a CR01B; I doubt if Bell could afford a Type 421.

I looked at the card reader instructions:
  crsf = 0706701
  crrb = 0706712
  crsb = 0706744

and it looks like it was a 421.

I don't know how much the Type 421 cost, but this was a well equipped
system: The Burroughs disk was one used as a swap device on KA10 time
sharing systems, and the graphics system was custom built, and
described as "as large as the CPU".  I believe it was the protype for
the Graphic II systems, capable of interactive filter circuit
analysis, which I imagine was useful to Ma Bell.

Bell Labs was responsible for the Karnaugh Map, the modern solar cell,
the transistor, the laser, the MOSFET, the communications satellite,
the discovery of cosmic background radiation, the first computer art,
the CCD, CFDM ... A research powerhouse, including a lot of basic
science.  It doesn't seem like any promising research topic was out of

I'm only surprised that the PDP-7 didn't have more than one 8K memory
bank (as I can't imagine they wouldn't have used it).  The display is
smart (there is discussion in [Sutherland68], that it may not qualify
for the next step on the the circle of reincarnation past the 340
because PDP-9 was largely idle and available to handle display list
updates) and the "hard work" (circuit analysis) was being done on a
GECOS mainframe....

The production Graphic II systems were PDP-9s, so I think it likely
Ken found the PDP-7 as a cast off prototype when 9's became available.


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