| 摘要 |
A magnetic tape drive system (20) records a directory block (CL) at a predetermined position on tape (22), and preferably at the beginning of tape. The directory includes, for each recorded track on tape (22), a data block number of the data block recorded at an end of the track. Preferably a plurality of copies of directory block (CL) are recorded, preferably in reverse direction. Upon receipt of a command to locate a target data block recorded on tape (22), a processor (102) directs a transport controller (82) to position a read element (30R) at the predetermined position on tape (22) for reading the directory. The read element reads the directory from tape (22). The processor (102) compares the target block number with the data block numbers stored in the directory and, in response to the comparison, causes an element positioner (74) via the transport controller (82) to position the read element with respect to the width of the tape (22) so as to read the track upon which the data block having the target data block number is recorded. The track upon which the target data is located is then sequentially searched for the target data block. |
