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The FP-6000 was a second-generation mainframe computer developed and built by Ferranti-Packard in the early 1960s. It is particularly notable for supporting multitasking, being one of the first commercial machines to do so. Only six FP-6000s were sold before the computer division of Ferranti-Packard was sold off by Ferranti's UK headquarters in 1963, the FP-6000 becoming the basis for the mid-range machines of the ICT 1900, which sold into the thousands in Europe.
What was to become the FP-6000 had its genesis in a Canadian Navy project starting in 1949 called DATAR. For DATAR, Ferranti-Packard (then still known as Ferranti Canada) built an experimental computer to share information among ships in a convoy. Although the prototype was a success, the failure rate of the vacuum tubes was a concern to everyone and Ferranti suggested they re-build the machine using transistors instead. DATAR ran out of funds before this conversion could take place, but Ferranti put the experience to good use in a series of one-off transistorized machines. One such example was a cheque sorting system built for the Federal Reserve Bank, itself a modification of a system developed to sort mail for the Canadian Post Office.
The developmental series eventually culminated in ReserVec. ReserVec was the first computerized reservation system to enter service when it took over all bookings for Air Canada in 1961. Ferranti initially had high hopes for the machine, thinking that it would be successful in Europe if sold by the UK headquarters' sales staff. As had happened many times in the past, however, the UK computer team suffered from a terminal case of not invented here, and decided it was better if they designed their own instead. Their project was never delivered, and ReserVec withered.
Ferranti-Packard was unwilling to simply let the development effort go to waste, and started looking for ways to commercialize the ReserVec hardware into a general purpose mainframe. Ferranti-Packard needed a launch customer to ensure at least one sale, and approached the Federal Reserve Bank again, offering a greatly expanded and more flexible system to replace the earlier custom-wired machine they had delivered only a few years earlier in 1958.
The design they settled on for the new machine, the ‘HARRIAC’, had been specified in England by one of Ferranti’s UK salesmen, Harry Johnson, as a commercial data-processing machine. HARRIAC had much in common with the Ferranti Argus series of process control computers, which date from 1958. The Argus, in turn, bore a strong family resemblance to the Ferranti Pegasus, whose architecture was strongly influenced by Christopher Strachey. The FP-6000 was implemented with discrete transistor logic circuits that had been developed by Maurice Gribble at Ferranti UK’s Wythenshawe plant, where they were known as ‘griblons’.
In order to be successful the machine would have to differentiate itself from the rest of the "seven dwarfs" in the US computer industry, which were having problems of their own given IBM's overwhelming presence. After some study they decided one up-and-coming area was multitasking (then known as multiprogramming), and started looking into ways for their computer to directly support it.
The key problem in supporting multiprogramming was the need for programs to be loaded into different locations in memory, so that more than one could run at the same time. Without multiprogramming a program was normally loaded into the "base" of memory, its notional location zero. In order to provide this environment for several programs, each program was assigned a fixed amount of the core memory, its base location being known as the datum and last location known as the limit. Every store operation by the CPU automatically offset the effective address by the datum. Most of these concepts had originally been developed for Ferranti UK's Ferranti Orion project, which several members of the FP-6000 team had worked on.
In order to prevent fragmentation of memory, each time a program terminated the FP-6000's operating system, known as Executive, would temporarily stop the other programs and recopy them to the lowest end of core. This way the available memory was always at the "top". Although this technique eliminated the need for storing a list of memory blocks, it was at the cost of expensive copies every time a program ended. This would make the system unsuitable for running an operating system such as Unix, which is "made up" of a series of tiny programs that are frequently started and stopped, but Unix did not exist at the time, and the model for most operating systems was a sort of "extended batch mode", running long-lived programs.
The machine was also designed from the outset to allow it to scale across a wide variety of needs. The system included 64 hardware channels that could be connected to peripherals of any sort, and could run with a wide variety of core memory sizes. In other ways the machine was fairly similar to the ReserVec's Gemini machine, using a 24-bit word with a 25-bit for parity checking and a simple machine language. One change was the lack of a memory drum, as the advances in core allowed them to replace the drum entirely.
Development of the FP-6000 was completed in late 1962, and the first production machine was delivered to the Federal Reserve Bank in early 1963. The prototype machine was later greatly expanded into the largest FP-6000 installation and sold to Saskatchewan Power, the provincial electrical supply crown corporation for use in performing both engineering calculations and customer billing simultaneously. From there additional sales proved very difficult. Over the next year they sold one to the Defence Research Establishment Atlantic, in Dartmouth, Nova Scotia and the other to the Toronto Stock Exchange (TSX). The later machine allowed the TSX to become the first computerized exchange a few years later. Sales attempts to the City of Toronto to drive the world's first computerized traffic control system failed, as did a sale to Ontario's Treasury department.
Sales by Ferranti UK were also non-existent. For years the Canadian division had to put up with not invented here problems and found their efforts continually blocked by the UK computer division's managers. It seemed that the FP-6000 was to suffer a similar fate, and the UK division had argued with the Canadian engineers about practically every part of the design. In fact the real reasons in this case would not become clear until later in the year.
Ferranti had been supporting their UK computer division for over a decade at this point, and had failed to make any significant sales. Management was tired of the drain on company resources, and decided to sell off the division entirely. They initially entered discussions with International Computers and Tabulators in early 1963, but ICT looked at the continual losses and was less than interested. Ferranti then "sweetened" the deal by showing them the FP-6000, offering to include that in the deal if ICT bought the division.
ICT was in the midst of re-designing its own series of low-end machines, and had been considering licensing an RCA IBM-compatible design. However the FP-6000 offered them a more attractive system that was deliberately not IBM-based, and could be scaled with the addition of smaller and larger machines to produce an entire line. ICT was finally interested, as one Ferranti board member put it, "without the FP-6000 we would not have gotten the deal we wanted from ICT. The FP-6000 was the golden brick in the sale of our operations.". The deal was announced in June 1963, to the surprise of the Canadian division.
The FP-6000, with the addition of the ICT Standard Interface, became the ICT 1904, and a slightly modified version would be offered as the 1905. The Canadian division offered to build both of these machines, which seemed obvious, as well as headquarters North American sales and marketing. However ICT was interested only in the European market, and declined on both offers. The entire hardware team resigned and formed an electronics company known as ESE, later purchased by Motorola. They were soon followed by the software team, who formed I. P. Sharp Associates, a major Canadian programming firm of the 1970s and 80s. The team in charge of the system's storage devices left some time later in 1967 to form Teklogix.
- ICL: A Business and Technical History, M. Campbell-Kelly, Clarendon Press, Oxford, 1989, ISBN 0-19-853918-5, p.221
- From DATAR To The FP-6000 Computer
- Rare Computer a Pioneer in Canadian History
- Time-Sharing on the Ferranti-Packard FP6000 Computer System
- The Ferranti Orion Computer System
- The Ferranti Argus Computer System