The interrupt request line is used by the card to signal the processor that the card requires the processors attention. IRQ2 to IRQ15 appear on the ISA bus. The DMA request line is used to transfer data between the peripheral card and the computers memory at high speed. DMA channel 0 cannot be used, as it is reserved for system use. This space is also sometimes used by a remote boot Eprom, which is used for diskless workstations which download the operating system from the server at boot time.
Peripheral cards require a software driver to function.
This software driver provides the interface between the card and the operating system, making the services provided by the card available to the user. The software driver is normally configured to match the resource settings of the card. It is obviously important for the configuration settings in the software driver to match those configured on the peripheral card. New cards can also be configured using a software program, rather than by manually setting jumpers on the card. Where cards are software configurable, the cards retain their configuration when the power is turned off.