Monrobot XI: Difference between revisions
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*[https://www.flickr.com/photos/24450270@N02/8305120263 photograph of Monrobot XI QUIKOMP(TM) reference card] |
*[https://www.flickr.com/photos/24450270@N02/8305120263 photograph of Monrobot XI QUIKOMP(TM) reference card] |
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*[http://www.computerhistory.org/collections/catalog/102621643 Monrobot XI datasheet] ([[Computer_History_Museum |Computer History Museum]] catalog entry) |
*[http://www.computerhistory.org/collections/catalog/102621643 Monrobot XI datasheet] ([[Computer_History_Museum |Computer History Museum]] catalog entry) |
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Revision as of 08:12, 18 December 2015
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The Monroe Calculating Machine Mark XI ("Monrobot XI") was a general-purpose digital computer introduced in 1960 by the Monroe Calculating Machine Division of Litton Industries.
Description
Upon introduction in May 1960[1], the Monorobot XI sold for US$24,500. In March 1961, the US Army reported[2] that 7 units had been made. In November 1961, the price remained unchanged and leasing ran US$700 monthly.[3]
It resembled an ordinary steel desk in length, breadth, and height, surmounted by an ordinary typewriter. At a weight of 375 pounds, its purveyors pronounced it portable.[4] It could operate outside of an air-conditioned room (tolerating +-25% voltage margins at 110F ambient), using a conventional mains power line (15 amp, 110 volt, 60 cps service) and about half as much electrical power (850W) as a toaster.
Save for the lamps in the control panel and 10-30 vacuum tubes employed for output devices, the electronics used only discrete solid-state components, including 383 transistors and 2,300 diodes. Construction was via pluggable printed-circuit boards. Its rewritable, persistent memory consisted of a rotating magnetic drum storing 1,024 words of 32-bits, which could record either a single integer or a pair of zero/single-address instructions. The average access time of 6,000 microseconds implies the drum made a rotation every 12 milliseconds, i.e. rotated at 83 and 1/3 Hertz. The high-speed registers of the computer also resided on the drum, but were replicated 16 times (with 16 times as many re-write heads distributed around the drum periphery), so that they might be read or written 16 times as fast as persistent memory. The arithmetic unit performed computations using the binary number system, with machine-language programming using hexadecimal digits, employing the unusual digit nomenclature set of 0,1,2,3,4,5,6,7,8,9,S,T,U,V,W,X.
Statistically, addition of 32-bit integers required 3ms to 9ms, multiplication 28ms to 34ms, and division 500ms. The longer durations reflect the mean latency (6ms) of accessing drum memory, rather than a register, for an operand.
The computer could be programmed using an assembly language system called QUIKOMP(TM), but its simple machine language instruction set and slow operation speed encouraged many programmers to code directly in machine language.
References
- ^ Recollections of the Monrobot by Norma Edwins, The Bulletin of the Computer Conservation Society (ISSN 0958-7403) #31, Autumn 2003
- ^ A Third Survey of Domestic Electronic Digital Computing Systems pg 0636ff. Report No. 1115, March 1961 by Martin H. Weik, Ballistic Research Laboratories, Aberdeen Proving Ground, Maryland ( US Army)
- ^ (November 1961 magazine ad)
- ^ Portable Robot The New Yorker (March 19, 1960)
External Links
- pg 75 (on the Monrobot XI) in Digitale Kleinrechner by Günter Schubert (Springer-Verlag, Mar 13, 2013)
- cover page of A Brief History of the Monrobot XI Computer by Donald O. Caselli, May 15, 2011
- photograph of Monrobot XI control panel
- photograph of Monrobot XI QUIKOMP(TM) reference card
- Monrobot XI datasheet (Computer History Museum catalog entry)
| This article, Monrobot XI, has recently been created via the Articles for creation process. Please check to see if the reviewer has accidentally left this template after accepting the draft and take appropriate action as necessary.
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