Early Computers at Stanford

Created 15 August 1997, last updated October 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


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 disk, rather than in random access memory (RAM) as used by later computers. The disk 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

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

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, called the Stanford Time-Sharing System. This 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, and was retired in 1965. 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 its Type 30 display was moved to the DEC PDP-6 at the DC 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. 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.

Hansen Applied Physics Lab

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

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.

Margaret Jacks Hall

The Stanford Artificial Intelligence project moved to 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.

A PDP-10 system for the CS department (SCORE) was also installed in the basement.

Xerox Altos

Perhaps 12 Xerox Altos computers were donated by Xerox corporation and installed on various floors 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.

Stanford Linear Accelerator Center

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. They had 2,097,152 8-bit bytes of memory each, and were programmed in Fortran.

Stanford Medical School


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 may have had an IBM 2321 data cell 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. 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 a PDP-10 in the Medical School. This PDP-10 used the KI-10 processor. It was programmed in InterLisp and used for the Stanford SUMEX-AIM National timeshared service.

Stanford Hospital

IBM System/360 model 40

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

Aero and Astro

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.

Center for Education Research at Stanford

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


LOTS started with a DECSYSTEM-20 with 524,288 36-bit words of memory in 1976 and later expanded to include several DECSYSTEM-20s and other DEC and IBM computers.

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 John Sauter from personal recollection.

We will update these webpages as the display takes shape.

Back to Computer History Exhibits page.