Timeline of Computer History


Tom Kilburn (standing) and colleagues at the Ferranti Mark I computer

Atlas computer

The concept of virtual memory emerges from a team under the direction of Tom Kilburn at the University of Manchester on its Atlas computer. Virtual memory permitted a computer to use its storage capacity to switch rapidly among multiple programs or users and was a key requirement for timesharing.


Woman holding deck of CRAM

Card Random Access Memory (CRAM)

Card Random Access Memory (CRAM) is introduced. The NCR 315 and several later NCR mainframes used this mechanically complex magnetic CRAM for secondary storage. The mylar cards were suspended from rods that selected and dropped one at a time for processing. Each CRAM deck of 256 cards recorded about 5.5 MB.


The IBM 1311 Disk Storage Drive

IBM 1311 Disk Storage Drive

IBM 1311 Disk Storage Drive is announced. Announced on October 11, 1962, the IBM 1311 was the first disk drive IBM made with a removable disk pack. Each pack weighed about ten pounds, held six disks, and had a capacity of 2 million characters. The disks rotated at 1,500 RPM and were accessed by a hydraulic actuator with one head per disk. The 1311 offered some of the advantages of both tapes and disks.


Kenneth Iverson, the developer of APL

Kenneth Iverson writes A Programming Language

Kenneth Iverson’s book A Programming Language details a form of mathematical notation that he had developed in the late 1950s while an assistant professor at Harvard University. IBM hired Iverson and it was there that APL evolved into a practical programming language. APL was widely used in scientific, financial, and especially actuarial applications. Powerful functions and operators in APL are expressed with special characters, resulting in very concise programs.


Wesley Clark with LINC

MIT LINC introduced

The LINC is an early and important example of a ‘personal computer,’ that is, a computer designed for only one user. It was designed by MIT Lincoln Laboratory engineer Wesley Clark. Under the auspices of a National Institutes of Health (NIH) grant, biomedical research faculty from around the United States came to a workshop at MIT to build their own LINCs, and then bring them back to their home institutions where they would be used. For research, Digital Equipment Corporation (DEC) supplied the components, and 50 original LINCs were made. The LINC was later commercialized by DEC and sold as the LINC-8.


Screenshot, SpaceWar!

Spacewar! debuts

MIT receives a DEC PDP-1 computer in the fall of 1961. While there were some demonstration programs, Steve “Slug” Russell thought a game would make a better presentation. Along with Martin "Shag" Graetz and Wayne Wiitanen, he designes a space battle game based on the Lensman series of novels by E.E. "Doc" Smith called Spacewar! Two ships, one called the 'Wedge' and the other the 'Needle,' would fly around a star-filled background. Peter Samson provided a program called Expensive Planetarium that generated an accurate star-filled background. The game would later be distributed through DECUS, the Digital Equipment Corporation users group, ensuring it would become widespread in the technical and university computing communities.


Chilton Atlas installation

The Atlas Computer debuts

A joint project of England’s Manchester University, Ferranti Computers, and Plessey, Atlas comes online nine years after Manchester’s computer lab begins exploring transistor technology. Atlas was the fastest computer in the world at the time and introduced the concept of “virtual memory,” that is, using a disk or drum as an extension of main memory. System control was provided through the Atlas Supervisor, which some consider to be the first true operating system.


RCA thin-film memory

Thin-film memory

Thin-film memory is introduced. Sperry Rand developed this faster variation on core memory. Small glass plates held tiny dots of magnetic metal film interconnected with printed drive and sense wires. Used in the UNIVAC 1107 for high-speed registers, it proved too expensive for general use. However, it did find a larger market in military computers and higher end projects where speed was a premium. Several other manufacturers, such as RCA, also developed thin-film memory.