The Standard Modular System (SMS) is a system of standard

transistor A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...

ized circuit boards and mounting racks developed by

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

in the late 1950s, originally for the

IBM 7030 Stretch The IBM 7030, also known as Stretch, was IBM's first transistorized supercomputer. It was the fastest computer in the world from 1961 until the first CDC 6600 became operational in 1964."Designed by Seymour Cray, the CDC 6600 was almost three tim ...

. They were used throughout IBM's second-generation computers, peripherals, the 7000 series, the 1400 series, and the

1620 Events January–March * January 7 – Ben Jonson's play ''News from the New World Discovered in the Moon'' is given its first performance, a presentation to King James I of England. In addition to dialogue about actual observ ...

. SMS was superseded by

Solid Logic Technology Solid Logic Technology (SLT) was IBM's method for hybrid packaging of electronic circuitry introduced in 1964 with the IBM System/360 series of computers. It was also used in the 1130, announced in 1965. IBM chose to design custom hybrid circu ...

(SLT) introduced with

System/360 The IBM System/360 (S/360) is a family of mainframe computer systems announced by IBM on April 7, 1964, and delivered between 1965 and 1978. System/360 was the first family of computers designed to cover both commercial and scientific applicati ...

in 1964, however they remained in use with legacy systems through the 1970s.

Overview

Many IBM peripheral devices that are 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 have SLT-type hybrid ICs mounted on them ''(see right)''. SMS cards are constructed of individual discrete components mounted on single-sided paper-epoxy

printed circuit board A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...

s. Single-width cards are 2.5 inches wide by 4.5 inches tall by 0.056 inches thick, with a 16-pin gold plated

edge connector An edge connector is the portion of a printed circuit board (PCB) consisting of signal trace, traces leading to the edge of the board that are intended to plug into a matching jack (connector), socket. The edge connector is a money-saving devic ...

. Double-width cards are 5.375 inches wide by 4.5 inches tall, with two 16-pin gold plated edge connectors. Contacts are labeled ''A–R'' (skipping ''I'' and ''O'') on the first edge connector, and ''S–Z, 1–8'' on the second. The cards are plugged into a card-cage back-plane and edge connector contacts connected to

wire wrap Close-up of a wire-wrap connection Typical wire wrap construction of crossbar_switch.html" ;"title="Bell System telephone crossbar switch">Bell System telephone crossbar switch. Some types of connection were soldered. Wire wrap is an electron ...

pins. All interconnections are made with wire-wrapped connections, except for power bus 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 can 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. The card type is a two- to four-letter code embossed on the card (e.g., ''MX, ALQ''). If the card has a "program cap" the code is 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 Digital usually refers to something using discrete digits, often binary digits. Businesses *Digital bank, a form of financial institution *Digital Equipment Corporation (DEC) or Digital, a computer company *Digital Research (DR or DRI), a software ...

logic families In computer engineering, a logic family is one of two related concepts: * A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compati ...

were implemented (ECL, RTL, DTL, etc.) as well as

analog circuit Analogue electronics () are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two levels. The term ''analogue'' describes the proportional relationship between a signal ...

s, to meet the requirements of the many different systems in which the cards were used. 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 Close-up of a wire-wrap connection Typical wire wrap construction of crossbar_switch.html" ;"title="Bell System telephone crossbar switch">Bell System telephone crossbar switch. Some types of connection were soldered. Wire wrap is an electron ...

ped

backplane A backplane or backplane system is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used to connect s ...

the same 1401 card cage File:IBM 7070.jpg, IBM 7070 card cage

References

External links

Customer Engineering Instruction-Reference, Standard Modular System
PDF

(dead link 10 March 2024) *http://ibm-1401.info/index.html ** http://ibm-1401.info/IBM-StandardModularSystem-Neff7.pdf
IBM SMS Cards Database
{{DEFAULTSORT:Standard IBM computer hardware IBM 700/7000 series IBM 1400 series

Overview

See also

References

External links