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EMIDEC hardware

These were the days of room-sized computers, running on transistors - strings of grey metal cabinets full of circuit cards and other gubbins. Main storage (actually known then as "core store") was a matrix of laced ferrite cores - quite visible in one of the cabinets. Main storage capacity was a monstrous 1,024 words, each of 36 bits - just over 4k in modern byte terms. Backing storage (equivalent of hard disk) was provided by magnetic drums rather than disks - to the extent of 4,096 registers - say 20k!! Anything else had to be stored on magnetic tape... that's one-inch wide magnetic tape in huge reels... as seen in contemporary films, whizzing backwards and forwards (though these really only went one way at a time unless they came across an "NCT error"), as the only moving objects worth filming.

Console

[MORE ON THE CONSOLE]


Card-reader
(manufactured by Elliott Automation)
This was the prime form of input for both data and programs.
[MORE ON PUNCH CARDS]

Paper tape reader
- a temperamental beast - only used for EMI Records sales order details
 

Anelex line printer
There was also a Samastronic printer, but it was older, bigger and slower, and rarely used.

[MORE ON THE LINE PRINTER]

Tape drives (Ampex)
Huge reels of one-inch magnetic tape mounted in the vertical drive, with its glass door. Loading the tapes was an art-form. One had to pull out just enough tape to allow for a loose loop at either side of the read/write head, and enough to wind round the receiving (bottom) reel to hold with friction. The drives were vacuum-sealed when the door was closed, and the vacuum was used to buffer the stop-start of the drive. If the size of the loops was wrong, the tape would snag; if insufficient tape was wound on to the receiving reel, the vaccuum would whip it off and flail it around inside the drive!

Tapes were stored in a bunker near the computer room - supposedly fireproof, it had a thick, heavy self-closing door.

 

Electronic gubbins
Circuit cards were about 8" square. There were racks of them in the cupboards which comprised the Emidec.

Circuit card - click to enlarge    Circuit card - click to enlarge    

See also Peter Wooledge's ICL website at http://www.vintage-icl-computers.com/icl44a.

Additional information and corrections gratefully received - click here to email me.