Standard Modular System: Difference between revisions

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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]].<ref>{{cite web|url=http://www.computer-museum.ru/books/archiv/ibm36040.pdf#page=18 |title=The 360 Revolution |last=Boyer |first=Chuck |date=April 2004 |publisher=IBM |page=18 |accessdate=25 November 2013}}</ref> They were used throughout IBM's second generation computers, peripherals, the [[IBM 700/7000 series|7000 series]], the [[IBM 1400 series|1400 series]], 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 SMS was superseded by [[Solid Logic Technology]] (SLT) introduced with [[System/360]] in 1964, however they remained in use with legacy systems through the 1970s.

Many IBM peripheral devices that were part of System/360, but were adapted from second-generation designs, continued to use SMS circuitry instead of the newer SLT. These included the [[IBNIBM 2400|240x-series tape drives]] and controllers, the [[IBM 2540|2540 card reader/punch]] and [[IBM 1403|1403N1 printer]], and the [[IBM 2821 Control Unit|2821 Integrated Control Unit]] for the 1403 and 2540. A few SMS cards used in System/360 peripheral devices even had SLT-type hybrid ICs mounted on them.

SMS cards were constructed of individual [[discrete component]]s mounted on single-sided paper-epoxy [[printed circuit board]]s. 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.