Patent ID: 8656094

Claim:
A computer program product, comprising: a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising: computer readable program code configured to receive a mount request to access at least one host data record on a virtual tape storage (VTS) system; computer readable program code configured to determine a number of host compressed data records per physical block on a magnetic tape medium by calculating a result of a formula, ((A−B)*C)/D, wherein A is a physical block size on the magnetic tape medium in bytes, B is a header size of a physical block on the magnetic tape medium in bytes, C is a compression ratio for the logical volume on the magnetic tape medium, and D is an uncompressed size of the requested at least one host data record; computer readable program code configured to determine a physical block ID (PBID) that corresponds to the requested at least one host data record; computer readable program code configured to access a physical block on the magnetic tape medium corresponding to the PBID; and computer readable program code configured to output the physical block without outputting an entire logical volume from the magnetic tape medium that the physical block is stored to.