Abstract: A computer system for using logical channel groups to indirectly address channels. The computer system includes a processor, a memory, and an input/output (IO) system for transferring information between devices and the processor. The IO system includes channels, channel path identifiers for identifying the channels, logical channel groups having lists of the channel path identifiers, and subchannels having pointers to the logical channel groups. The IO system also includes one or more switches for routing information between the channels and devices.