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On the first floor of Bridge House North - around the middle of 1963 - there were 2 * 1301's - Did they have the following configurations??:
 | P3/1
http://www.cs.nott.ac.uk/~ef/ComputerXHistory/FirstComputers-2/1963-ICT1500-GeneralView.htm for this picture - the caption of which read "The 1301 electronic data processing system - here installed as a punched card machine at the ICT Computer Centre, Putney Bridge House, London SW6"
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| P3/2
 thanks to
http://web.onetel.com/~rodritab/shed13.htm for this picture - which looks
to be incredibly similar to P3/2 - but I don't remember all the glasswork at
the rear - so it may not be.
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| Card Reader - 600 cpm |
| Card Punch - 100 cpm |
| Line Printer - 600 lpm |
| 2 Drums each of 12,000 Words * |
| Core Memory of 2,000 Words |
| 6 * 1 inch Ampex Tape Decks - transfer rate was 90Kc's - per second.. (digits) |
Memory was 48 bit Words - split into 2 * 24 bit half-words, or 12 * 4 bit Characters
Instruction Format was something like:
| Instruction or Indicator = bits 1 to 8 (left to right) |
| Modifier = bits 9 to 12 - if 8 - Sets, if 9 - Clears, the Programmed Indicators |
| Address = bits 13 to 24 |
Remembered (or not??) Instructions:
| 37 - Load Register B |
| 40 - Saves Register A to memory and Clears it |
| 41 - Store Register A |
| 42 - Store Register B |
| 80, 81, 82 and 83 were Drum transfers - either to or from |
| 00 - with a Modifier of 4 - was an Unconditional Jump |
| 01 - 29 with a Modifier of 4 - was a Test Indicator (programmed were 01 to 10), (Operator Console were 20 to 29) and Jump |
| 38 - was a basic peripheral instruction - anything from Read a Card to Drop a Sprag (on the printer) whilst lifting the others (for paper movement) |
| 39 - was for Mag Tape transfers |
| 60 to 69 - were arithmetic instructions |
| 70 to 79 - were (similar to 60 to 69) complicated Sterling (before decimalisation) arithmetic instructions ( there was no hardware Divide) - can you imagine in one instruction, performing a Multiply of ? 17/14/7 by 365 - i.e. Multiply 17 Pounds 14 Shillings and 7 Pence by 365 - if you're interested, the result is... ? 6,471/2/11 - there were 12 Pence to a Shilling and 20 Shillings to a Pound |
Update!! Update!! As at May 10th I've had some feedback and corrected some of the mis-remembered specs above - more soon...and thanks...