Method And Apparatus for Logically Disconnecting And Connecting an I/O Device to a Central Processor
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-16
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.