Patent ID: 6226712
Filing Date: 2001-05-01
Classification: G06F

Abstract:
A computer implemented method of reversing from a first data record address to a target data record address of machine-readable data stored on a direct access storage device (DASD), said DASD containing a portion of a logically ordered sequence of digital data stored on a backup sequential storage medium, the portion of the logically ordered sequence including:at least one data record;a target data record;a record header preceding each of the data records, the record header includinga first record header having a first data record address;a target record header having a target data record address;said method of reversing to the target data record address comprising:receiving identification of the target data record including the target record header having an address, the target data record being located sequentially prior to the first record header;if the data records are not equi-sized, starting at the first record header and repeatedly advancing to prior records one record header at a time;if the data records are equi-sized, using data portion trailer information to identify the address of the target record header preceding the target data record; andlocating to the target record header.