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Method And Apparatus for Logically Disconnecting And Connecting an I/O Device to a Central Processor

IP.com Disclosure Number: IPCOM000059556D
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-16

Publishing Venue

IBM

Related People

Authors:
McGee, HT Yudenfriend, HM [+details]

Abstract

An I/O device can be physically connected to several central processing units (CPUs) by components that include device control units, interconnecting busses, and switches that are operable to interconnect the components along a selected path. When an operating system has physical access to a device and all the information and authority that is necessary for transmitting messages on the physical path, the device is said to be "logically" connected to a CPU. When service personnel are going to physically disconnect a control unit from a CPU, they must first logically disconnect the associated devices. Commonly, operating personnel enter appropriate commands into each CPU that is logically connected to these devices.