A system and method for hot swapping daughtercards in high availability computer
systems. In one embodiment, a high availability computer system includes a peripheral
bus. Daughtercards may be added to the computer system by inserting them into connectors
associated with the peripheral bus. The daughtercards are configured to allow their
insertion or removal from the computer system without interruption to system operations.
When inserted into a computer system, a daughtercard may be powered up by power
control circuitry on the daughtercard. When the daughtercard is powered up, it
may then assert a configuration change signal. The computer system may then respond
to the assertion of the configuration change signal by establishing software communications
with the daughtercard. The configuration change signal may be driven to a storage
unit located within a bus interface unit of the computer system. The state of the
configuration change signal may be stored within a storage location of the storage
unit. The storage location in which the state of a configuration change signal
is stored for a given daughtercard is exclusive to that daughtercard. Thus, when
a computer system detects the assertion of a configuration change signal, it may
immediately make a determination as to which daughtercard asserted the signal.
