[pdp7-unix] card readers (was ald)

Bob Supnik bob at supnik.org
Tue Oct 22 20:48:45 AEST 2019

The 18b PDP service listing (from 1972) says that PDP-7 serial #34 (the 
Bell Labs Unix machine) has a CR01B. The CR01B and the 421 have 
identical IOTs, hence the confusion. See pages 81 and 86 of the PDP-7 


On 10/21/2019 10:59 PM, Phil Budne via pdp7-unix wrote:
> 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
> bounds.
> 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.
> [Sutherland68]
> http://cva.stanford.edu/classes/cs99s/papers/myer-sutherland-design-of-display-processors.pdf
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