Parity storage unit, in a disk array system, for generating updated parity data from received data records

A storage unit system having at least one storage unit including recording media for storing original information as at least one data record and redundant information for recovering the original information as at least one parity record, comprising:

• a control unit for executing transfer operations between a host processor and the storage unit;
• said control means receiving updated data records from the host processor and pre-update data records from the storage unit;
• said control unit having means for generating intermediate information from updated and pre-updated data records;
• said control unit having means for sending the generated intermediate information to the storage unit;
• said storage unit having means for receiving intermediate information from said control unit, means for reading at least one pre-update parity record corresponding to the received intermediate information, means for generating at least one updated parity record from the intermediate information and the at least one pre-update parity record read from said recording media;
• and
• means for writing said transferred updated data records and said at least one parity record on said recording media.

A storage unit system having a plurality of storage units for storing data including recording media for storing original data records and redundant parity records for recovering the original data records, comprising:

• a control unit for executing transfer operations between a host processor and the storage units including means for broadcasting a set of updated values of the data records to said storage units;
• said storage units including at least one first storage unit having recording media for storing data records and at least one second storage unit having recording media for storing parity records;
• said first storage unit having means for receiving the broadcast set of updated values of the data records, means for selecting updated values of the data records from the received set of values to be written on the first recording media, and means for writing the selected updated values of the data records to the recording media;
• and
• said second storage unit having means for receiving the pre-update values of the data records from one of the control unit and the first storage unit, means for receiving the broadcast set of updated values of the data records, means for reading at least one pre-update parity record from the recording media corresponding to the received set of values, means for generating at least one updated parity record from the received set of broadcast updated values of the data records, and means for writing the updated parity value generated by said generating means on the recording media.

A storage unit system having a plurality of storage units for storing data including recording media for storing m number (m≧1) of data records and n number (n≧1) of parity records storing redundant data for restoring the data record wherein the data records and parity records together constitute a parity group of m+n records, comprising:

• a control unit for executing transfer operations between a host processor and the storage units;
• said control unit having means for broadcasting a logical record to the storage units upon receiving a write request for the logical records;
• first ones of said storage units having recording media for storing data records, means for receiving the broadcast set of logical records from the control unit, means for underwriting an updated value of the received data record to recording media, means for sending pre-updated values of the data record corresponding to the received updated values of the data records to at least one of the control unit and other storage units;
• and
• second storage units having recording media for storing parity records, means for receiving the pre-update values for the data records from the first storage unit, means for receiving the logical records from the control unit, means for reading at least one pre-update parity record from the recording media corresponding to the value of the data records, means for generating at least one updated parity record from the received set of values of the data records, the received pre-update values of the data records and the at least one pre-update parity record read from the recording media, and means for writing the updated parity values generated by said generating means on the recording media.