Massachusetts Institute of Technology, Tapes of Tech Square (ToTS) collection

The Tapes of Tech Square (ToTS) project at CSAIL (Computer Science and Artificial Intelligence Lab) started in the early 1990s to preserve historical records on data backup tapes from MIT's Artificial Intelligence (AI) Lab and Lab for Computer Science (LCS), the precursors of CSAIL. Both of these labs occupied offices in MIT building NE43 known as Tech Square.[1][2]

The MIT Laboratory for Computer Science (LCS) was a laboratory for research in computer science and engineering, first established on July 1, 1963, as Project MAC in the Department of Electrical Engineering. By 1967, MAC had separated from the Electrical Engineering Department and started reporting directly to the MIT provost as an interdepartmental lab. The name Laboratory for Computer Science was chosen in 1975 and officially recognized in 1976. In 1981, while retaining its interdepartmental status, LCS came under the aegis of the School of Engineering, and the LCS director began reporting to the dean of engineering. The MIT Artificial Intelligence Laboratory (AI Lab) was established in 1959 and was a separate lab from LCS, focusing primarily on artificial intelligence. On July 1, 2003, the Laboratory for Computer Science (LCS) merged with the Artificial Intelligence Laboratory (AI) to form the CSAIL.[3][4]

The files in this collection come from backup tapes of computers and systems used by these labs. Below are short descriptions of these systems, their acronyms, and context around how and when they were used:

ITS (the Incompatible Timesharing System) was the operating system written at the AI Lab and LCS to run on Digital Equipment Corporation computers of the 36-bit family; these were some of the DEC PDP (Programmed Data Processor) models. ITS was named by its authors in contrast with CTSS (the Compatible Time-Sharing System) running on the IBM 7094 system then at MIT.

The AI Lab's first such computer was a PDP-6. This was succeeded around 1970 by a PDP-10, KA model, the AI-KA. LCS also acquired a couple of KAs in the next few years, DM (mostly used by the Dynamic Modelling Group) and later ML (primarily used by the MathLab Group). It should be noted that the DynaMod Group used a somewhat different dumping scheme for DM than was used for all the other ITS machines. DM was also the only ITS machine (until the middle 1980s) to have a 9-track tape drive; all the others had 7-track drives.

When the Macsyma program was ready for somewhat general use by its sponsors (mostly US government agencies), the MC (Macsyma Consortium) machine was acquired for their use of it. MC was a later, KL model of the PDP-10. During the last year of its life at MIT, the MC-KL was renamed MX for technical reasons. DEC had written its own operating system for the PDP-10, TOPS-10 -- but so had other CS research centers. In particular, the hackers at Bolt, Beranek, & Newman wrote what they called the TENEX system. DEC later acquired rights to TENEX, and used it as the base for its next PDP-10-type operating system, which it called TOPS-20. This was written for DEC's next model in its 36-bit family, the DEC-20, which under its skin was remarkably similar to a DEC-10-KL (same CPU, different memory and I/O channels). Hackers who knew its history regularly referred to Tops-20 as TWENEX.

LCS acquired the XX DEC-20 machine in the late 1970s, and the AI Lab acquired OZ in the early 1980s -- in each case to begin to shift its research groups off the ITS machines.

The KAs limped along into the early 1980s before being shut off, and MC continued through 1986 -- when some new, physically smaller DEC-20s arrived. These were of the KS model, and ITS was adapted to run on them (this was mostly a matter of rewriting the microcode). The AI, MC, ML, and MD KSs were in operation for the later part of the 1980s, although only the AI and MC machines were much used. In fact, it was intended that the MD machine could be shut down and a version of TWENEX brought up on it – in which case it would be referred to as MIT-LSD; this happened no more than a few times. Separately the labs also acquired a 5th KS, which did run TWENEX as its regular operating system; this machine was named BLT (Brave Little Toaster) after a science fiction story.

The AI Lab and LCS DEC-20s lasted until the end of the 1980s, when the labs fully shifted to smaller, per-group and later personal computers running varieties and descendants of Unix.[1]

[1] “Intro-to-ToTS,” Massachusetts Institute of Technology, Tapes of Tech Square (TOTS) collection, MC-0741. Massachusetts Institute of Technology, Department of Distinctive Collections, Cambridge, Massachusetts [2] “MIT Leaves behind a Rich History in Tech Square,” March 17, 2004. https://news.mit.edu/2004/techsquare-0317. [3] “Biographical/Historical Note.” Massachusetts Institute of Technology, Laboratory for Computer Science records, AC-0268. Massachusetts Institute of Technology, Department of Distinctive Collections, Cambridge, Massachusetts. Accessed April 23, 2020. https://archivesspace.mit.edu/repositories/2/resources/228. [4] “Mission & History.” MIT CSAIL. Accessed April 23, 2020. https://www.csail.mit.edu/about/mission-history.