Input/Output Configuration Program: Difference between revisions

Revision as of 14:02, 26 August 2023

Revision as of 06:07, 9 September 2023

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| date = January 1987}}</ref> mode, IBM changed the I/O architecture to allow the [[Channel Subsystem]] to handle the channel scheduling that the operating system handled in S/370 mode. The new I/O architecture used a 16-bit '''subchannel number''', a 16-bit '''device number''' and an 8-bit '''Channel Path Identifier''' ('''Channel Path Id''' or '''CHPID'''); the [[Channel Subsystem]] was responsible for mapping the '''subchannel number''' to the channel and device numbers, for queuing I/O requests and for selecting from the available paths.

Starting with [[IBM zZ#IBM zSeries family|z990]], IBM introduced the concept of a '''Logical Channel Subsystem'''<ref>{{cite manual

| title = IBM IBM eServer zSeries 990 Technical Guide

| id = SG24-6947-01