Digital Equipment Corporation PDP–7/A - S#109

The PDP–7 Service list (1972) shows that machine #109 was shipped to MIT in January 1970 and consisted of the following options –

OptionS#ShipDEC #Notes
14900006901700100774K memory upgrade to 8K
1750000210170010077Information collector expansion.
177B0000150170010077Extended arithmetic element
3400000220170010077Precision Incremental CRT Display
3420000110170010077Symbol generator for 340 display, first 64 characters.
347C0000050170010077340 Display Subroutine Interface
3700001090170010077Photomultiplier Light Pen
550A0000420170010077DECtape control, (up to 4x 555's)
5550001120170010077DECtape control, (up to 4x 555's)
KA71A0000090170010077I/O device package
KA77A0000090170010077Processor unit
TU550001900170010077Single DECtape transport
TU550002180170010077Single DECtape transport
TU55000497017018267Single DECtape transport
TU55000508017018267Single DECtape transport

For descriptions of the above options see the full PDP–7 options list.

Digital Equipment Corporation PDP–7/A S#109 was installed at Massachusetts Institute of Technology (MIT) in the Education Research Center.

120 PDP–7 and PDP–7/A systems were forecast to be built in total, but the 1972 18–bit service list available (6.5Mb pdf download) only has details of the 99 known PDP–7 and PDP–7/A systems in the list at that time.  We do not have any information about the possible remaining 21 systems, who they were delivered to or even if they actually existed.

The PDP–7 appeared to have sold well into Government research and University sectors with 11 systems shipped to the UK alone, almost 10% of the forecast production run!  Serial numbers are concurrent for both PDP–7's and the PDP–7/A's, so the missing 21 could be of either type; however we are reasonably confident that the 99 systems shipped were the only ones that were ever built.

If you know of any information about any of the PDP–7 systems worldwide, options, location of existing systems, spare parts, ancillary bits, software, tapes or manuals, then please contact us.

Documents associated with PDP–7 S#109 - None at this time

An email from Jordin Kare [bio] (April 2013) has given us some more information about this system –
"I believe I was one of the last owners (as it were) of PDP–7/A Serial 109, which was originally sold to the Education Research Center at MIT.  The machine was used to make physics simulation films, using a 347 display and one–frame–at–a–time camera.  One simulation I recall was a road lined with telephone poles, shown as though you were driving past them at relativistic speed.  By 1974, when I arrived at MIT, it had been turned over to the MIT Electronics Research Society (MITERS), the student electronics club, of which I became president.  It was equipped with (as I recall after all these years) the display, including the character generator (with wire–rope ROM), 8K of core, and two 555 dec–tape units.  I don't think I have any photos of the machine, alas, and I don't know where it finally ended up.  I do still have the aluminium rod with microswitches attached that was my personal SpaceWar controller for the –7."

Apparently the PDP–7/A at MITERS was called "Bertha"!

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