Status Register Masking
Original Publication Date: 1980-Nov-01
Included in the Prior Art Database: 2005-Feb-14
An I/O controller (IOC) in an I/O communications subsystem can sense and set status register bits in a communications adapter (CA) status register without interference with adapter circuitry which can also set bits in the same status register. Each bit of the status register represents a unique event, and under normal conditions, the service time for the event is less than the time during which the same event can reoccur. A masking arrangement eliminates the need for a duplicate status register and gating circuits which would otherwise be required to eliminate the interference. It also simplifies the microcode support required to service CA functions.