An ICL 2904 mini-mainframe was installed at Downs Surgical Ltd., Church Path, around 1978.
The company had previously used two Honeywell computers: a 716 and a 2020. Both were batch processing machines, with no interactive terminals. The ICL 2904 came with direct data entry terminals for fast entry of orders, and also Multi-Access terminals, for which an online Sales Order Processing system was written in COBOL. The ICL 2904 operating system including a terminal message routing system and a ‘riro’ file for ‘rolling-in and ‘rolling-out’ large Transaction Processing programs.
The ICL 2904 computer was based on the ICL 1900 series of computers and used a six-bit character instead of the 8-bit byte used today. This meant that the character set did not have lower case letters. The EDS60 drive, ‘Exchangeable Disc System 60’, would hold up to 60 million of these six-bit characters. One of the drives had to be online when the computer was started as it contain the ‘boot’ system. The other two drives could be used for other programs. Typically during the day they would hold the indexed sequential orders file that was updated from the terminals using the Sales Order Processing system. In the evening other disc were put online to perform batch processing. Backups were taken to magnetic tapes.
The operating system used disc based spooling of output from batch programs. This meant that as batch jobs finished their output was written to file for printing later. The operator controlled what printouts were then spooled from disc to the printer, as he might also have to change the stationery, e.g. invoices etc. In the event of a failure with the printer this spool file could be taken off site to another ICL 2904 customer to use their printer. Heron Suzuki in Beddington Lane was frequently used for this purpose.
An operator was recruited with ICL 1900 series experience to work on the 2904, and was paid £3,600 per year.