ICF Prime Computers

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The Prime 400 was delivered to RAL on 3 December 1976 and started an internal service to users in January 1977. The initial configuration was:

• PRIME 400 CPU
• 192K bytes of 600ns memory
• 2 × 80 Mbyte moving head disc units
• 200 char/sec paper tape reader
• 75 char/sec paper tape punch
• 300 cpm card reader
• 300 lpm line printer (64 char set)
• Magnetic tape (9-TRACK 800 bpi NRZI)
• 16 line asynchronous controller (speeds to 19200 bps)
• 2 line synchronous controller (speeds to 9600 bps).

The machine was a great success and turned out to have twice the CPU power of the GEC 4070 but the 4070 performed well interactively when the workload was not over-demanding. In consequence, the decision was made to install Prime systems in demanding environments and GEC systems in less demanding ones.

For the next 12 years, Prime systems were a major part of the UK academic engineering community's interactive computing facilities. About 30 systems were installed in 9 locations with models being replaced my larger systems as the programme expanded.

These pages give some of the history of the involvement with Prime. A more formal presentation is given in the paper, Prime and the UK Academic Engineering Community, by Mike Jane.

The FORTRAN system on the PRIMEs was enhanced by software written locally. FINGS was a simple interactive graphics system. ROOTS was a sophisticated structured programming tool that allowed FORTRAN programs to be developed in a robust and structured way. Two translator writing systems, TREE-META and META II were used in developing user-friendly front-ends to a number of products.