All Purpose Electronic X-Ray Computer
An All Purpose Electronic X-Ray Computer ( APEXC ) is an early series of simply structured computers that were developed from 1952 by Andrew D. Booth at Birkbeck College in London . From 1943 he researched in the field of crystal structure analysis . There were different models and the X in the name was replaced with a different letter on later models. This is also what we call the APEC series.
Models
- APEXC (London, from 1952, later further developed), operation via punch cards
- APENC (N for Norway, Oslo), ditto
- APEHC (H for Hollerith ), operated by telex ( punched tape )
- APERC (R for Rayon)
- UCC (University College, London, 1956)
- MAC (Magnetic Automatic Calculator, 1955)
- HEC 1-HEC 4 (Hollerith Electronic Computer, from around 1951–1955)
description
The description applies to the APEXC (according to documents from 1957).
The APEXC had 32 magnetic drum memories , but neither RAM nor ROM . To simplify matters, all commands and operators were 32 bits long. The memory addresses were 10 bits long.
Since the usual command counter (PC) did not exist, the start address of the next command was included in the commands. There were only 15 commands.
A keyboard with 32 keys or the punched tape were used for input. The output took place via a printer or also via punched tape.
emulation
The APEXC is supported by the M.ESS emulator .
predecessor
The APEXC wasn't the first computer Andrew Donald Booth created. After the ARC (Automatic Relay Computer, 1947-1949), he developed the SEC (Simple Electronic Computer) in 1949.