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Hardware Detail

Item Reference:
HW0281    
Machine Type:
705
Serial Number:
  Console from RAPC 705
  The IBM 705 system comprised of three main sections: an input machine that placed data taken from punched cards onto magnetic“ tape; the ‘computer’ which consisted of ten magnetic tape readers and a central processing unit that carried out the calculations, controlled through the operator’s console and finally, a printer unit that published a wide range of forms and documents.

The computer system was controlled by one of the most complex programmes ever devised, with almost 74,000 separate instructions located within 250 sub routines. It was estimated to have taken the equivalent of almost ninety years of programming time to devise.

The information on a soldier's pay account was stored on magnetic tape at a density of 200 characters per inch or 22.5mm, i.e. 7745356 Johnson-Smith would take twenty characters or use approximately 1/10" of an inch or 2.5mm. A complete soldier’s account would vary according to the individuals circumstances i.e. married with dependants or drawing specialist pay but would usually occupy 2 - 7 inches or 150-180 mm of tape. Each magnetic tape reel could hold almost 60,000 characters.

Although the CPU could process data at 60,000 characters per second, the calculations were slowed by the operational speed of the mechanical card reader (250 cards per minute) and the printer. A single printer supported the whole system, producing examples of up to sixty different forms, with forty-five being used on a daily basis.

These are the components that comprised the 705 system:

  • 705 Central Processing Unit - with Core Memory
  • 714 & 759 Card Reader and Card Reader Control Unit
  • 717 & 757 Printer and Printer Control Unit
  • 722 & 758 Card Punch and Card Punch Control Unit
  • 727 Magnetic Tape Unit
  • 754 Tape Control Unit
  • 734 Magnetic Drum Storage Unit
  • 775 Record Storage Unit


This machine was used to process the data from the 1961 U.K. census. You can read an article from the Soldier magazine about the 705's introduction here.

Console Typewriter

The typewriter on the Type 705 can be used to print directly from memory, one character at a time. The speed of typing is approximately 600 characters per minute. All other operations of the machine are held up during the typing operation.

The typewriter has a 12" carriage and is equipped with a pin feed platen. Maximum length of writing line is 8 7/8", overall form width 9 7/8", and hole-to-hole dimension is 9 3/8". Any character not on the code chart prints as a question mark. A plus zero and a minus zero print as a plus sign and a hyphen respectively. Sensing the record mark automatically causes a carriage return and automatic spacing in accordance with the setting of the space control on the carriage.
Date of Origin:
1954
Donor:
RAPC

705

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705

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705

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705

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705

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Location:
On Display - HLG19 Commissioned By: Museum Until: