Patent ID: 7290070

Claim:
A method of extending the functionality of channel subsystems, said method comprising: configuring a channel subsystem as a plurality of channel subsystem images, said channel subsystem directing a flow of information between one or more input/output devices and main storage coupled to the channel subsystem, and said channel subsystem comprising at least: a first channel subsystem image identified by a first channel subsystem image identifier, said first channel subsystem image appearing to a program as an independent channel subsystem and comprising a first set of one or more channel paths and a first multiple image facility (MIF) having one or more MIF images, each of said one or more MIF images being identified by a MIF image identifier (IID); and a second channel subsystem image identified by a second channel subsystem image identifier, said second channel subsystem image appearing to a program as an independent channel subsystem and comprising a second set of one or more channel paths and a second multiple image facility having one or more MIF images, each of said one or more MIF images of the second MIF being identified by a MIF image identifier (IID); and identifying a channel path of the first set of channel paths by a concatenation of the first channel subsystem image identifier and a first channel path identifier, and a channel path of the second set of channel paths by a concatenation of the second channel subsystem image identifier and a second channel path identifier.