Controller (computing): Difference between revisions

Revision as of 23:08, 27 July 2014

Revision as of 23:52, 29 July 2016

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]]In IBM terminology a ''controller'' is "a device that decodes the [channel] command and effects the operation of the device."<ref>{{cite book|last=IBM Corporation|title=Introduction to IBM Data Processing Systems|year=1978|url=http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/generalInfo/GC20-1684-4_IBMdpIntroJul78.pdf}}</ref>{{rp|p.5-1}}

In most mainframe systems a device-independent [[Channel I/O|''channel'']] usually attaches to the CPU and to a controller or control unit which implements device-dependent logic for attaching specific devices. The functions performed by the control unit are similar to the channel.functions performed by a [[device driver]] program on smaller systems. Some devices have integrated control units, which are logically discrete but are included with the device rather than requiring a separate box. Often a control unit can attach to multiple channels connected to a single or multiple systems. Some mainframe control units are:

* [[IBM 2821 Control Unit]], used to attach card readers, punches and line printers to IBM System/360 and IBM System/370 computers

* [[IBM 270x]] and [[IBM 37xx]], used for telecommunications