Standard Modular System: Difference between revisions

Revision as of 21:14, 1 May 2010

Revision as of 04:00, 5 May 2010

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[[File:SMScard.jpg|thumb|A single width SMS card.]]

The '''Standard Modular System (SMS)''' was a system of standard [[transistor]]ized circuit boards and mounting racks developed by [[IBM]] in the late 1950s, originally for the [[IBM 7030 Stretch]].{{factCitation needed|date=May 2010}} They were used throughout IBM's second generation computers and peripherals, including its first transistorized calculator, the [[IBM 608]],<ref>http://www.columbia.edu/acis/history/608.html</ref> and the [[IBM 700/7000 series|7000]] and [[IBM 1400 series|1400]] lines and the [[IBM 1620|1620]]. SMS was superseded by [[Solid Logic Technology]] (SLT) introduced with [[System/360]] in 1964, however they remained in use with legacy systems through the 1970s.

SMS cards were constructed of individual [[discrete component]]s mounted on single sided paper-epoxy [[printed circuit]] boards. Single width cards were 2.5 &nbsp;inches wide by 4.5 &nbsp;inches tall by 0.056 &nbsp;inches thick, with a 16 pin [[gold]] plated [[edge connector]]. Double width cards were 5.375 &nbsp;inches wide by 4.5 &nbsp;inches tall, with two 16 pin gold plated edge connectors. Contacts were labeled ''A–R'' (skipping ''I'' and ''O'') on the first edge connector, and ''S–Z, 1–8'' on the second.

Some card types could be customized via a "program cap" (a double rail metal jumper bar with 15 connections) that could be cut to change the circuit configuration. Card types with a "program cap" came with it precut for the standard configuration and if a Customer Engineer needed a different configuration in the field he could make additional cuts as needed. This feature was intended to reduce the number of different card types a Customer Engineer had to carry with him to the customer's site.

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== References ==

{{reflistReflist}}

==External links==

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[[Category:IBM computers]]

[[Category:IBM 700/7000 series]]

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