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### Prime Systems and the ICF

An Overview of Prime's system developments is:

- 1972: Prime 200
- The first Prime system, similar to the DDP 516 but a 32-bit machine with paging
- 1973: Prime 100 and Prime 300
- The Prime 100 was a stripped down version of the Prime 200 (no memory parity or floating point). The Prime 300 was the current system at the time ICF was being launched.
- 1976: Prime 400
- By 1977, the Prime 300 was being replaced by the Prime 400. The Prime 300 was withdrawn in 1979. The ICF Prime 400 arrived in December 1977.
- 1979: Prime 450, 550, 650 ,750
- The Prime 550 was an upgrade in performance over the Prime 400 while the Prime 750 was a major upgrade which was very competitive with a similarly priced DEC VAX System. PRIMENET and the local area network software RINGNET were announced. Four Prime 550 systems were installed in 1979 and 1980. Prime 750 systems were installed at RAL and UMIST.
- 1980: Prime 150 and 250
- 1981: Prime 850
- Prime also marketed MEDUSA CAD Software
- 1982: Prime 2250
- 1984: Prime 2550, 9650, 9750
- 1985: Prime 9955, 9655, 2655
- A Prime 9955 was installed at UMIST and a Prime 9655 at Nottingham in 1985
- 1986: Prime 2350, 2450, 9755, and 9955-II
- 1987: Prime 2455, 2755, 6350, and 6550

A summary of the Prime systems installed by ICF is:

Location | Initial Machine | Intermediate Machine(s) | Final Machine | ||
---|---|---|---|---|---|

Date | Type | Date | Type | ||

RAL (Services) | 1977 | P400 | 2 × P400; 2 × P750 | 1986 | P9955 |

RAL (Dev) | 1977 | P300 | P400; P550/1 | 1986 | P9655 |

Sussex | 1979 | P550/1 | - | - | - |

City | 1980 | P550/1 | - | 1986 | P750 |

Surrey | 1980 | P550/1 | - | 1986 | P550/2 |

UCL | 1980 | P550/1 | - | 1986 | P750 |

UMIST | 1980 | P750 | P9950 | 1985 | P9955/1 |

Warwick | 1980 | P550/1 | P550/2 | 1986 | P750 |

East Anglia | 1979 | P400 | - | 1986 | P750 |

Nottingham | 1977 | P400 | - | 1985 | P9655 |

The original Prime 400 ran at 0.5 MIPS, had a main store of 192 Kbytes and 160 Mbytes of disc storage. Typical configurations for the main systems used by ICF were:

P550 | P750 | P9955 | |
---|---|---|---|

MIPS | 0.7 | 1.0 | 4.0 |

Memory (Mbytes) | 1.0 | 2.0 - 4.0 | 8.0 - 12.0 |

Disc Space (Mbytes) | 500 | 1200 | 2700 |

Magnetic Tape Unit (9 track) |
1 | 1 | 1 |

Printers | 1 | 1 | 1 |

Plotters | 1 | 1 | 1 |