Disk array controller for data storage system

A disk array controller system is configurable to perform data transfer operations between a host system and a various disk drives configurations as a RAID level 1, 3, 4 or 5 disk array. The controller system includes a plurality of array channels (21-25) for coupling selected disk drives with a host system bus (16) and circuitry (110) for generating parity information during write operations. Each array channel (21-25) includes a data bus connected through bus drivers to the host bus (16), its associated disk drive, and the input and output of the parity generation circuitry (110). The bus drivers control the placement of data onto the array busses (21-25) and the direction of the data flow on the array busses (21-25). The system can also be configured to check parity information, recover lost data, reconstruct disk drives, monitor data transfer operations, verify data transfer operations and broadcast information to a plurality of disk drives.