The Manchester MUSE/Atlas Project

Tom Kilburn started a project called MUSE in the fall of 1956 at University of Manchester. The name MUSE was chosen as a shorthand for microSEcond because the goal of the project was to design and build a computer with a speed of one million instructions per second. If successful, the new computer would be over one thousand times faster than the Mark 1, the university's then current computer (it should be noted that the first Mercury computer was delivered to the university in 1957 and went into production in early 1958).

It soon became clear that a computer as fast as the one being contemplated could not be used efficiently if it was used to run jobs in series¹ as was done on all then existing computer systems. In fact, as the project evolved, it became apparent that a whole series of innovations would be required in order for the project to be successful.

The project was renamed as the Atlas Project in 1959. Ferranti joined the project later the same year to alleviate the project's funding and manpower problems. Ferranti was an obvious choice as a partner as it had been contracted in 1948 to build production versions of the Mark 1.

The first Atlas computer became operational on December 7, 1962. It was 2400 times faster than the Mark 1 and 80 times faster than Manchester's then current Mercury. By the time that the full supervisor program (i.e. operating system) became operational in 1964, the system took advantage of the following new inventions and technologies:

• multiprogramming (i.e. the ability to run more than one job at once)
• job scheduling
• spooling
• interrupts
• pipelining
• interleaved storage
• autonomous transfer units (i.e. independent 'processors' responsible for transfering data to/from main memory)
• virtual memory and paging
• associative memory
• a virtual computer environment for user programs (i.e. they saw an abstract computer as opposed to the bare hardware) and (pseudo) parallel processes within a program
• an operating system large enough to not be entirely resident in memory at all times
• programatic interfaces (i.e. APIs) between user programs and the operating system

There were other similar projects underway at the same time, notably the LARC and IBM's Stretch projects, which were developing equivalent technologies. It isn't necessarily clear which projects developed which technologies first. The Atlas was the first computer to implement virtual memory.

In the end, only two Atlas computers were built. Although a market failure, the Atlas is notable for the innovations that it (solely and jointly with the LARC and Stretch projects) brought to the field of computing.

The last Atlas went offline in September of 1971. Tom Kilburn died on January 7, 2001.

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¹Each job would be run to completion before the next job was started.

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Sources

• Various web pages at http://www.computer50.org/, a site at the University of Manchester celebrating the birth of the modern computer.