US Patent 8964327 Tape storage device, data writing method, and program

A tape drive receives multiple write requests for data pieces and a synchronization request corresponding to the write requests from a device, performs a synchronization process, and returns a completion status of the synchronization request. The tape drive includes a write controller that stores data pieces transferred from the device in the buffer, according to a first write request, receives a first synchronization request and then a subsequent write request for at least one data piece, and returns the completion status when processing for the first synchronization request is completed and the subsequent write request is received with a command queuing function.