The longest running computer owned by C&A was the Computer Control Company's DDP-224. 3C, as they were called, specialised in computers for digital data processing (thus the name DDP). Bill Poduska, Robert Baron and others who developed the DDP-124 later started the Prime computer company after 3C was taken over by Hewlett-Packard.
C&A's main responsibility was processing data captured on particle physics equipment both at Rutherford and CERN. Data was frequently captured on film that needed to be scanned to find information of interest. The DDP-224 initially was the interface between the scanning equipment and the mainframe that was to process the data. It was also used to handle three counter experiments. It later performed a secondary role of interfacing computer terminals to the mainframe.
The DDP-224 was installed in May 1965 and later augmented with additional core store, magnetic tape decks, a Calcomp graph-plotter, and the IDI visual display with light pen. It could handle several real-time input devices at the same time.
The Orion was replaced by the IBM 360/75 in September 1966 and the DDP-224 performed the same tasks as before but using a faster DMA channel attached to the 360/75. A complex data link was designed and constructed to connect the DDP-224 to the 360/75 through an IBM 2701 data adaptor. A system called DAEDALUS was written to allow 24 separate devices to transfer information to the 360/75. These included 8 teletypes. PDP8 and other devices connected to NIMROD were attached to the 360/75 via the DDP-224.
By 1973, the 360/195 was up and running and by then the DDP-224 was no longer the only satellite computer attached to the mainframe. It continued to support CYCLOPS and HPD-1 but two DDP-516s and two IBM-1130s were also attached to handle a range of other input devices including HPD-2.
The Fully Buffered Channel (FBC) allowed an external I/O device to communicate directly with memory modules for transfers at very high speed. Once set up and enabled by the computer program, the address of the sequential memory locations to be accessed was supplied by the FBC independent of the computer program. The maximum channel transfer rate was 166K characters/sec and capable of supporting the interactive IDI display.
For further information on the DDP-224-based satellite system and associated devices developed at Rutherford Laboratory see:
David Lord moved from Rutherford to CERN in June 1966. In the period 1976-1983 he was responsible for the IBM System at CERN that was closely linked to the Rutherford IBM System. He also was responsible for the site network and the introduction of wide area network communications.
The DDP-24 was fully program compatible with the later DDP-224 but additional facilities were added to the DDP-224. A full description of DAP II can be found in Honeywell Computer Control Division's DAP II Manual: DDP-24, DDP-124 and DDP-224 General Purpose Computers, 1966. Not currently available online.
