Early Computers at Stanford

Created 15 August 1997, last updated December 16, 2007.

This is part of information collected for the Computer History Exhibits.

Please send corrections and updates to Gio Wiederhold, email <gio@cs.stanford.edu> and to John Sauter <John_Sauter at systemeyescomputerstore.com>. The intent is to list all computers at Stanford up to about 1980, when personal computers became ubiquitous and uncountable. Some major, later equipment can be included.

Electronics Lab (1953 to 1962)


In March of 1953 an IBM CPC arrived at the Electronics Lab. The CPC was an IBM 604 plugboard calculator driven by a program on punch cards. Although the IBM 604 used vacuum tubes, the program was not stored electronically; it was read from cards as it was executed, at a rate of 100 cards per minute. The storage unit held 16 10-digit signed numbers. The CPC was retired in 1956. See http://infolab.stanford.edu/pub/voy/museum/pictures/display/1-2-IBM-CPC.htm.

IBM 650

The first stored-program computer at the Electronics Lab was an IBM 650. It arrived in January of 1956 and was retired around 1962. This was a drum computer, meaning that the program and data resided on a rotating magnetic drum, rather than in random access memory (RAM) as used by later computers. The drum held 2000 10-digit words. An add instruction required 400 microseconds, and a multiply 10,000. The IBM 650, like the IBM 604, used vacuum tubes. Later versions of the IBM 650 had 60 words of core memory, but they were intended to be used as an I/O buffer.

Encina Hall (1960 to about 1965)

Burroughs Datatron B220

There was a Burroughs Datatron B220 at Encina Hall starting in June of 1960. This was a vacuum-tube computer with 10,000 44-bit words of core, each containing 10 decimal digits. Core memory was a new technology, replacing drum memory with magnetic cores. This was called Random-Access Memory (RAM) because you could access any word of memory in the same time as any other word.

The add instruction executed in 185 microseconds and multiply in about 2095. The B220 was shared with the First National Bank of San Jose, which used it for overnight check processing.

John Sauter remembers seeing the computer in the mid-1960s, but we do not have a date for its retirement. The computer was programmed in Balgol, the Burroughs dialect of Algol-60.

Pine Hall (1963 to 1980)

Pine Hall was Stanford's “Computation Center” in the 1960s.

IBM 7090

The IBM 7090 was a fully transister-based, room-size computer, with 32,768 36-bit words of core memory and a 2.18 microsecond cycle time. It performed an add instructon in 4.8 microseconds, and a multiply in typically 25 microseconds.

Vistors to Pine Hall could see the IBM 7090 through through a glass wall. Nearest the observer was the console, from which the operator could observe the machine's internal registers. At the back of the room was an IBM 1401, which provided card-to-tape and tape-to-print and -card punch services for the IBM 7090, which was therefore able to read its input from and write its output to magnetic tape.

The IBM 7090 was installed in approximately February of 1963, and retired in May of 1967. In its early years it was also used by IBM San Jose. In its later years it acquired an IBM 1301 disk, which it shared with the nearby DEC PDP-1, and a CDC 8090 to augment the IBM 1401.

A notable improvement in productivity was achieved when Stanford programmers were able to make the IBM 1401 copy simultaneously from card reader to tape and from tape to printer and card punch. Previously, the IBM 1401 could copy in only one direction at a time.

The IBM 7090 provided general computer service to campus users, including the Artificial Intelligence project (Lisp and Chess). Classes were offered in programming the IBM 7090. The machine ran IBM's Fortran Monitor System, which automatically loaded the next job from magnetic tape when the previous one finished. In addition to Fortran and the FAP assembler, the IBM 7090 was programmed in Subalgol, the Stanford dialect of Balgol, which was the Burroughs dialect of Algol-60.

Burroughs B5000/B5500

The Burroughs B5000 was another fully-transisterized, room-size computer, installed in the room to the right of the IBM 7090 from the point of view of the observer looking through the glass wall.

This machine was based on advanced computer concepts for its day, as contrasted with the IBM 7090, which stressed compatibility with earlier IBM computers. It was installed in approximately March of 1963, and retired in 1968. It was upgraded to a Burroughs B5500, which ran at three times the speed of the B5000 and offered a second CPU. Due to software limitations, the second CPU could only execute in user-mode; an attempt to enter the operating system would cause it to signal the main CPU for attention.

The B5000 had 16,384 48-bit words of memory. It was programmed in Algol-60 with extensions for I/O and string processing. Late in its life the B5500 switched off its drum storage and used disks instead.

The Burroughs computer provided general computation service to the campus, including classes on Algol-60 and validation of Algol programs submitted for publication as algorithms.


The PDP-1 was to the left of the IBM 7090, but was not visible to observers, lacking a glass wall. This was a much smaller-scale computer than the IBM 7090, used for research in computer-based learning, artificial intelligence, and games. A time-sharing system was developed for the PDP-1, formally named the Stanford Time Sharing System, though it also went by the names Zeus and Odin. Time sharing allowed people at separate consoles to use the PDP-1 simultaneously, a great increase in productivity.

The PDP-1 arrived sometime before May of 1963. Early in its life it was upgraded from 4,096 18-bit words to 65,536. When the IBM 7090 acquired its IBM 1301 disk drive, the PDP-1 was interfaced to it through the IBM 7631 file control. The PDP-1 was also interfaced directly to the IBM 7090, and could submit jobs to it using the Bifrost software. This interface was also used to visualize IBM 7090 data in real time using the PDP-1's Type 30 CRT display. See http://ccrma.stanford.edu/guides/planetccrma/Some.html for an example. When the PDP-1 was retired, probably in 1966 or 1967, its Type 30 display was moved to the DEC PDP-6 at the D.C. Power Lab.

In support of its time-sharing mission the PDP-1 was equipped with a high-speed magnetic drum, which could write 4,096 words of memory onto a track in one revolution, and simultaneously read 4,096 words from a different track and write them into those same memory locations. This was called “swapping”.

IBM System/360 model 67

In May of 1967 an IBM System/360 model 67 replaced the IBM 7090, Burroughs B5500 and DEC PDP-1 in Pine Hall. There is some question about whether this machine was a model 65 or model 67, but John Sauter remembers seeing the lights of the “Blaauw Box”, the dynamic address translation module that is the difference between the models, and Glen Herrmannsfeldt remembers that it was always described as a model 67. However, despite the dynamic relocaton capability, the model 67 was run as a model 65 using IBM's OS/360 operating system.

This machine had 524,288 8-bit bytes of memory. It could perform an add in 1.5 microseconds, a multiply in 6.


Mark Crispin and Rich Alderson remember a DECSYSTEM-20, possibly named CONTEXT, at the computer center in the early 1980s. It was supposed to be used for editing and e-mail only.


Mark Crispin remembers that the SCORE DECSYSTEM-20 was originally installed in Pine Hall in 1979 and moved to the Computer Science Department's then-new digs in Margaret Jacks Hall in 1980. There is more information about the computers in Margaret Jacks Hall below.

IBM System/360 model 30

Mark also remembers an IBM System/360 model 30 in Pine Hall at that time. It could perform an add in 29 microseconds, a multiply in 303. It was used for Remote Job Entry to the big IBM iron which was in another building.

Hansen Experimental Physics Lab (early 1970s)

IBM 7700

HEPL had an IBM 7700 with 16,384 36-bit words of memory for data acquisition from experiments. The machine is believed to have been at the lab in the early 1970s. See http://infolab.stanford.edu/pub/voy/museum/pictures/IBM.html.

D.C. Power Lab (1965 to 1979)

The D.C. Power Laboratory housed the Stanford Artificial Intelligence project beginning in 1965. See http://infolab.stanford.edu/pub/voy/museum/pictures/AIlab.html and http://en.wikipedia.org/wiki/Stanford_AI_Lab.


The first computer installed at the D.C. Power Lab was a DEC PDP-6, delivered in June of 1966. It had 65,536 36-bit words of core memory and a high-speed Librascope disk. This system was primarily used for artificial intelligence research, including the programming languages LISP and SAIL, and for chess and checkers. There were three versions of the “robot arm”, used for research into manipulation.


In 1968 the PDP-6 was augmented by a PDP-10 processor, the KA10, resulting in a dual-processor system. Memory was expanded from 65,536 to 196,608 36-bit words.

Later an IBM 2314 disk array was added for additional data storage. The time-sharing operating system written at SAIL, known as WAITS, was based on the PDP-6 Monitor, provided by Digital Equipment Corporation (DEC).

See http://infolab.stanford.edu/pub/voy/museum/pictures/display/1-7.htm .

Mark Crispin remembers that when he arrived in 1977 there were two processors in the PDP-10 system: the KA10 described above and a KL10, the fastest processor in the PDP-10 line. User jobs were run on the KL10 and the KA10 ran the XGP font compiler and user jobs (in "spacewar mode", formerly the task of the PDP-6 processor).

The PDP-6 had by then become a separate computer, though it booted from the PDP-10. It operated the computer music devices. Rich Alderson remembers that it was retired in 1984.

Margaret Jacks Hall (1979 to 1983)

The Stanford Artificial Intelligence project moved to the basement of the Margaret Jacks Hall in 1979.


A DEC PDP-10 with a KL10 processor and 524,288 36-bit words of memory was installed there.


Mark Crispin remembers that SCORE, a consortium of the Computer Science Department, two Electrical Engineering laboratories and Operations Research, purchased a DECSYSTEM-2050 in 1979. It was first installed in Pine Hall and then moved to Margaret Jacks Hall.


When the Computer Science Department sold its interest in the SCORE system to its partners in 1983, the DECSYSTEM-2050 moved to Electrical Engineering and was renamed SUCHI. The Computer Science Department bought a new DECSYSTEM-2060 which had the first 4-RP07 public file system. Its size, 2,064,384 8-bit bytes, astonished DEC Field Service.

Xerox Altos

Perhaps 12 Xerox Altos computers were installed in Margaret Jacks Hall in 1982. They featured a What-You-See-Is-What-You-Get (WYSIWYG) text editor, but the Smalltalk language was not provided.

Electrical Engineering (1983)


When the Computer Science Department sold its interest in the SCORE system to its partners in 1983, the DECSYSTEM-2050 moved to Electrical Engineering and was renamed SUCHI.


Rich Alderson remembers that there was also a DECSYSTEM-2060 at Electrical Engineering called SIERRA.

Stanford Linear Accelerator Center (1965 to 1981)

IBM System/360 model 50

SLAC ordered an IBM System/360 model 91 from IBM, and as a result received the slower but software-compatible System/360 model 50 in June of 1965. This machine had 262,144 8-bit bytes of memory, and could perform an add in 4 microseconds, a multiply in 16.

IBM System/360 model 75

The model 50 was replaced by the model 75 with 1,048,576 bytes of memory in 1967. This machine could do an add in 0.75 microseconds and a multiply in 3.

IBM System/360 model 91

The model 91 arrived in 1968 and was retired August 21, 1981. It had 2,097,152 8-bit bytes of memory and could do an add in 0.2 microseconds, a multiply in 0.4. It was programmed in Fortran.

IBM System/370 model 168

In 1973 SLAC installed two IBM System/370 model 168s. Glen Herrmannsfeldt remembers that these computers each had 3,145,278 8-bit bytes of memory. They were programmed in Fortran.

Stanford Medical School (1964 to about 1992)


In the south wing of the basement the Genetics Lab had a DEC/ NIH LINC computer with 4,096 12-bit words in 1964.

IBM System/360 model 50

From December of 1965 until 1973 an IBM System/360 model 50 was the principal computer of ACME. It had 131,072 8-bit bytes of memory plus an extension that provided 1,048,576 (later 2,097,152) additional bytes of lower-speed memory. This system had an IBM 2321 data cell drive, holding tape strips, given the huge capacity (for the time) of about 400,000,000 8-bit bytes. This device was famous for its unreliability.

The model 50 also had four IBM 2311 disk drives, at about 7,250,000 8-bit bytes each, later replaced by an 8-drive IBM 2314, with 29,176,000 8-bit bytes per drive.

The computer was programmed in a subset of PL/I and offered timesharing. See also http://infolab.stanford.edu/pub/voy/museum/pictures/IBM.html.

IBM 1800

From approximately May of 1966 until the 1970s the IBM 1800 acted as a real-time sub-processor for the ACME system. It had 16,384 16-bit words of memory and was programmed in PL/I.


From some time in the 1970s until around 1992 there was the SUMEX timeshared computer service in the Medical School. It was supported by NIH and NLM and provided services to medical researchers throughout the United States, focusing on AU applications. The principal investigator was Prof. Joshua Lederberg and the manger was Tom Rindfleisch. Prof. Feigenbaum, Bruce Buchanan, and other researchers from the Computer Science were involved as well. It was used by Ted Shortliffe and others to develop the Mycin advice giving systems, the prototype for future experts system technologies. Ted Shortliffe later joined the Stanford faculty and started the Medical Information Science group at Stanford.

Its equipment was primarly a PDP-10. Mark Crispin remembers this PDP-10 having two KI10 processors in 1977. It was programmed in InterLisp and used for the Stanford SUMEX-AIM National timeshared service. It ran the Tenex operating system.


In about 1979 SUMEX acquired a DECSYSTEM-2020 called Tiny. Mark Crispin acquired that machine when it retired.


At some point in the early 1980s, SUMEX replaced its dual KI10 Tenex system with a DECSYSTEM-2060. By 1989 the 2060 had been upgraded to a 2065.

Stanford Hospital (about 1970)

IBM System/360 model 40

An IBM System/360 model 40 was used at Stanford Hospital starting about 1970.

Aero and Astro (about 1960 to about 1970)

IBM 1620

Some time in the 1960s there was an IBM 1620 in Durand with 20,000 4-bit digits of memory. It was used for development of the Least Mean Squares algorithms.

SDS Sigma 5

In about 1967 there was an SDS Sigma 5 in the Durand basement. This was a 32-bit computer.

Hewlett-Packard 2116

Also in the Durand basement in about 1967 was an HP 2116.


In about 1970 the Durand held an Adage computer, an analog system used for 3D matrix transforms. This may have been an Adage Ambilog or an Agage AGT-30. See http://www.virhistory.com/ncsu/ncsu_lab.htm

Data General Eclipse

Some time in the 1970s there was a Data General Eclipse in the Durand basement.

Institute for Mathematical Studies in the Social Sciences (1977 to 1989)


Mark Crispin remembers that there was a PDP-10 at IMSSS in 1977, using a KI10 processor and running the Tenex operating system. At some point in the early 1980s IMSSS acquired a second KI10 processor from Rutgers and became a dual KI10 system like SUMEX. Rich Alderson remembers this system still being in place in 1989.

Center for Education Research at Stanford (1976 to 1989)

The computers used by the Low-Overhead Time Sharing project ( LOTS) were located in an old TV studio at the Center for Educatonal Research at Stanford (CERAS).


LOTS started with a DECSYSTEM-2040 with 524,288 36-bit words of memory in 1976. It ran the TOPS-20 operating system. Mark Crispin remembers that by the late 1970s the DECSYSTEM-2040 had become a DECSYSTEM-2050, and a second DECSYSTEM-20 computer had arrived. Patrick Scheible remembers the second DECSYSTEM-20 as LESS, meaning “LOTS' Even Slower Sister”

System Concepts SC-30

Rich Alderson remembers that the last PDP-10-type system at Stanford was the System Concepts SC-30 at LOTS. It was acquired in 1986.

By 1989 LOTS had three DECSYSTEM-2065s named Lear, Othello and Hamlet, the SC-30 named Macbeth, and other computers.

Graduate School of Business (1978)


Mark Crispin remembers that the Graduate School of Business acquired a DECSYSTEM-2040 by 1978.


Mark Crispin remembers the DECSYSTEM-2040 being upgraded to a DECSYSTEM-2050, and a second machine was acquired later. Rich Alderson remembers that these two computers were named HOW and WHY.

Center for the Study of Language and Information (some time in the 1980s)


Rich Alderson remembers that there was a DECSYSTEM-20 at CSLI in the 1980s. It may have been the former CONTEXT machine from the computer center.

This page was first created on 15 August 1997 by Gio Wiederhold, email: gio@cs.stanford.edu.

Base material was collected by Voy Wiederhold, coordinator, email: voy@db.stanford.edu, using Stanford Daily and Library sources. Additional material was provided by Gio Wiederhold, John Sauter (1963-1968), Mark Crispin (from 1977), Rich Alderson (1980s), Patrick Scheible and Glen Herrmannsfeldt from personal recollection.

John Sauter and Gio Wiederhold will update these web pages as we obtain more information on early Computers at Stanford University.

Back to Computer History Exhibits page.