The Elliott 903 was manufactured by Elliott Automation Limited from 1965 as a desk-sized successor to the military computers 920B (in Nimrod Mark I) and 920M (in RAF Jaguars and in tanks). It had an 18-bit word ferrite core store with a 6 microsecond cycle time, paper tape I/O and a Teletype. Up to 64K words of store could be fitted in units of 8K. The 905 was a later faster machine which could have 128K words of store.

The machine used transistors on plug-in packages. Peripherals could include a plotter, a line printer, magnetic tapes, industrial interfaces, and displays for plant monitoring. There was no disk to act as a focus for an operating system, although one based on magnetic tape was written and several for real-time applications.

Counting the military versions probably about 1000 machines were sold. The 903 itself was used in process control, for running laboratory equipment in hospitals and elsewhere, and for teaching programming in schools. Languages available included Algol, Basic, Coral, Fortran and the SIR assembler. This emulator has Algol although it can also be run with SIR programs.

There is one emulator for the Elliott 903 available here and two collections of additional material. Note, however, that not all the files referred to in the additional material are available here as yet.

64	sim900al.zip contains an emulator by Terry Froggatt and Don Hunter.
64	plotal.zip has additional material supporting the attached plotter.
	readmes.zip being notes concerning the above.
	to an area containing Elliott 903 material from Andrew Herbert. Here may be found a 900 series simulator, associated tools and demonstration programs for Microsoft Windows 7 software and manuals distributed by Elliotts to Elliott 920, 903 and 905 customers software and manuals distributed by Elliott’s Airborne Computing Division to its customers software written by Andrew software written by other Elliott 903 users.