The interrupt specification is the information the system needs to link the device interrupt source with a specific device interrupt handler. The specification describes the information provided by the hardware to the system when making an interrupt request. Because an interrupt specification is bus specific, the information it contains varies from bus to bus.
Interrupt specifications typically include a bus-interrupt level. For vectored interrupts the specifications include an interrupt vector. On x86 platforms the interrupt specification defines the relative interrupt priority of the device. Because interrupt specifications are bus specific, see isa(4), eisa(4), mca(4),sbus(4), vme(4), and pci(4) for information on interrupt specifications for these buses.