| 摘要 |
A storage subsystem comprises a pair of control units (21,23) coupling a plurality of channels (5,7,9) to a plurality of data storage device (27,29). Each control unit includes a plurality of registers (351, 352) for storing error check and status data. A communications link (31) couples the register sets together. When a fault condition is discovered in one of the control units, an unavilability signal is sent to the operatively coupled channel and an alert signal, through link 31, to the other control unit for storage in one of the registers. When this registers is addressed in a polling operation, said other control unit allows transfer of the register data to its own registers. Meanwhile, a selective reset reply from the channel is buffered until the register data has been transferred to prevent erasure of this data before transfer. |
