2201 BPI   Part No: 40052099
Serial number: 970946

Following our request for any further information, Martin Gregorie has kindly offered the following notes:

"The unit in your picture looks remarkably like the single platter hard disks that the ICL 2903 used as its system disk. 

These system disks held 5 MB of data, but I don't know what the physical arrangement was.

The ICL 2903 was a 'large desk sized' system consisting of a single bolt-together unit containing the operator's console, CPU, system disk drive, card reader and printer. The CPU was actually a 2900 DFC running microcode to emulate 1900 hardware. It ran a UDAS Executive which could host George 1* (a modified version of George 2, since it could spool print jobs) and a DDE subsystem that allowed data entry from small, dedicated terminals. It could also run an OLTP system that supported ICL's 24x80 block-mode terminals as well as the DDE terminals.

It could run virtually all ICL 1900 utility programs. Programming was officially limited to RPG and COBOL, though I also wrote PLAN 3 on it - use of the compiler was officially forbidden, but a simple ALTER after loading it soon fixed that and was trivial to add to a George 1* macro."