Standard Modular System: Difference between revisions

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{{Short description|IBM computer circuit board, circa 1960}}

{{Refimprove|date=May 2010}}

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

{{Other uses|IBM SMS (disambiguation){{!}}IBM SMS}}

[[File:IBM SMS Card (8372882397).jpg|thumb|An SMS card with an [[Solid Logic Technology|SLT]] device at far right (the square metal piece)]]

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

The '''Standard Modular System''' ('''SMS)''') wasis 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>{{Citationcite web|url=http://www.computer-museum.ru/books/archiv/ibm36040.pdf#page=18 |title=The 360 Revolution |last=Boyer |first=Chuck needed|date=MayApril 2004 |publisher=IBM |page=18 |accessdate=25 November 20102013}}</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 SMS was superseded by [[Solid Logic Technology]] (SLT) introduced with [[System/360]] in 1964, however they remained in use with legacy systems through the 1970s.

==Overview==

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 240x-series tape drives and controllers, the 2540 card reader/punch and 1403N1 printer, and the 2821 Integrated Control Unit for the 1403 and 2540. A few SMS cards used in System/360 peripheral devices even had SLT-type hybrid IC's mounted on them.

[[File:IBM 1401 card cage.jpg|thumb|SMS cards in an [[IBM 1401]] mid-sized computer]]

Many IBM peripheral devices that wereare part of System/360, but were adapted from second-generation designs, continued to use SMS circuitry instead of the newer SLT. These included the [[IBM 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 hadhave SLT-type hybrid IC'sICs mounted on them ''(see right)''.

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

The cards wereare plugged into a card-cage back-plane and edge connector contacts connected to [[wire wrap]] pins. All interconnections wereare made with wire-wrapped connections, except for power bussbus lines. The back-plane wire-wrap connections were mostly made at the factory with automated equipment, but the wire-wrap technology facilitated field-installation of engineering changes by customer engineers.

Some card types couldcan 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 Customercustomer Engineerengineer 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 Customercustomer Engineerengineer had to carry with him to the customer's site.

The card type wasis a two- to four -letter code imbossedembossed on the card (e.g., ''MX, ALQ''). If the card hadhas a "program cap" the code wasis split into a two -letter card type code and a two -letter "cap connection" code (e.g., ''AK ZZ'').

When SMS was originally developed, IBM anticipated a set of a couple hundred standard card types would be all that would be needed, making design, manufacture and servicing simpler. Unfortunately that proved far too optimistic as the number of different SMS card types soon grew to well over 2500. Part of the reason for the growth was that multiple [[Digital data|digital]] [[logic families]] were implemented (ECL, RTL, DTL, etc.) as well as [[analog circuit]]s, to meet the requirements of the many different systems in which the cards were used in.

<gallery>

File:IBM SMS card component side.jpg|SMS card from an IBM 1401

File:IBM SMS card circuit side.agr.jpg.jpg|Circuit side of same SMS card

File:IBM SMS card, front.jpg|SMS card, front

File:IBM SMS card, back.jpg|SMS card, back

File:SMS card with power transistors.jpg|SMS card from an IBM 1401

File:IBM 1401 card cage 2.agr.jpg|IBM 1401 card cage

File:IBM 1401 backplane.jpg|[[Wire wrap]]ped [[backplane]] the same 1401 card cage

File:IBM 7070.jpg|IBM 7070 card cage

</gallery>

== See also ==

* [[IBM Solid Logic Technology]]

* [[Flip-Chip module]]

== References ==

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==External links==

*[http://www.piercefuller.com/scan/ibm-223-6900-2.pdf?id=ibm-223-6900-2 Customer Engineering Instruction-Reference, Standard Modular System] PDF

*[http://members.optushome.com.au/intaretro/SMSCards.htm IBM's Standard Modular System (SMS) cards] (dead link 10 March 2024)

*http://ibm-1401.info/index.html

** http://ibm-1401.info/IBM-StandardModularSystem-Neff7.pdf

*[http://files.righto.com/sms/ IBM SMS Cards Database]

{{DEFAULTSORT:Standard}}

[[Category:IBM computerscomputer hardware]]

[[Category:IBM 700/7000 series]]

[[Category:IBM 1400 series]]