Patent ID: 8438332

Claim:
A method to maintain write operation atomicity if a data transfer operation crosses a data storage medium track boundary, comprising: supplying a primary storage controller comprising two clusters wherein each cluster comprises a host adapter, a processor, and a NVS; receiving by a first cluster host adapter from a host computer a write request and data; determining by a first cluster processor if said write request will cross a data storage medium track boundary; operative if said write request will cross a data storage medium track boundary: indicating by said first cluster processor to said first cluster host adapter that said write request comprises a two-track transfer; writing a first track comprising a portion of said data to said first cluster NVS as the data is received; writing a second track comprising a portion of said data to a second cluster NVS as the data is received; operative if said host computer fails prior to providing all the data to said primary storage controller, discarding said data written to said first cluster NVS and said second cluster NVS.