Multi-Adapter Identification Register
Original Publication Date: 1988-Apr-01
Included in the Prior Art Database: 2005-Feb-15
Computers like the RT PC which do not have vectored interrupts on the I/O bus require the processor to poll all adapters of the same type that share an interrupt level to determine which of the adapters is interrupting. Polling operations of this type result in unnecessary use of processor cycles and thus unduly increases the time to service adapter I/O interrupts. This is critical in the case where data can be lost if the interrupts are not serviced fast enough. A method is described which solves the problem of polling adapters on an unvectored interrupt I/O bus where multiple adapters of the same type may reside on the same interrupt level. This method requires the program to poll a single register rather than multiple adapter registers to determine the adapter creating the interrupt.