Technology Square

Entrance sign

Technology Square was the nickname for MIT building NE43, which housed Project MAC - later split into the AI Lab and the Laboratory for Computer Science (including the Dynamic Modeling, Mathlab, and Macsyma Consortium groups). Its formal address was '545 Technology Square', but everyone just called it by the shortened form, Tech Sq.

The machine room was always on the top (9th) floor, which walmost all raised floor. The other floors held mostly offices (with occasional interjections, such as the DSSR/RTS group's small machine room om the 5th floor - even though DSSR/RTS itself was mostly housed on the 4th floor).

9th floor layout

Originally, the 9th floor held MIT's second CTSS machine, and the GE-635 and GE-645 of the Multics project.

Later on, space around the outer walls where the CTSS/Multics machines used to be was turned into enclosed offices; the remainder of that space was used to hold the MIT-MC KL10 ITS machine.

Floor plan (click to enlarge)

(A ping-pong table was behind MC, between it and the outer wall at the end of the building; this was later dispensed with, so the space could be used to hold the CSR group's PDP-11/40. Later the /40's CPU was swapped to EECS - they wanted it for a second front end on the EECS DECSYSTEM-20, which was named 'DeepThought' - for a PDP-11/45, which had been the EECS DELPHI machine, on which quite a few years of CS undergrads learned to program. Sic transit gloria mundi.)

The ARPANET IMPs (eventually three of them, in the C/30 generation) were along the outer sidewall where it says '1401'. The MIT-XX DECSYSTEM-20 TOPS-20 machine was installed right next them, along a new wall built approximately where the two pillars are; its disk drives were along the outer wall.

The MIT-DM KA10 ITS machine was between the DM PDP-6 and the MIT-ML KA10 ITS machine (which was mostly along the outer wall, with its DEC disk drives in front of it), and also along the outer wall behind that PDP-6. When the RKS10 ITS machines arrived, they went where ML used to be.

The Dover was eventually installed between the two doors into the lobby, on that side of the building.

Technology Square and NE43 in 1994

As the other end, the offices 919-922 were done away with, and that all became open raised floor, initally holding various robot arms, the Xerox Graphics Printer, etc, etc; later, CADR LISP machines were there (and elsewhere). The AI ITS KA10 was later replaced with the MIT-OZ TOPS-20 DECSYSTEM-20.

External links

• Tech Square - Description at Multicians.Org
• Technology Square (Cambridge, Massachusetts) - Wikipedia page
• MIT leaves behind a rich history in Tech Square
• Computer Resources - from the '1975 MIT Lab for Computer Science Brochure'; it includes some very rare images of the 9th floor machine room
• NE43 Memory Project Forum
• ABC docmentary "What About Tomorrow? - On The Side Of Man" from January 1973 has plenty of footage from inside Tech Square