Abstract: A data transfer device adapted to transfer data from a data storage medium having at least one data storage element the data transfer device comprising a head block having first and second transfer elements. The first and second transfer elements arranged such that, when, in use, the data storage medium moves past the first and second transfer elements said at least one data storage element is aligned with both of said first and second data transfer elements. The first data transfer element is arranged to read data from a portion of said at least one data storage element at a different time to the second data transfer element being arranged to read data from said portion of said at least one data storage element.

Abstract: A data storage device comprises a removable and replaceable magnetic tape cassette provided with a software control write protect switch. The switch is adapted to have a first condition in which data may be written to said magnetic tape and a second condition in which said switch is adapted to cause the blocking of a write operation to said tape. The switch is contained within a non-volatile electronic memory device and is electronically configurable between its first and second conditions remotely via a control signal.

Abstract: Data are stored on magnetic tape along successive tracks extending obliquely across the tape, in each of several areas including a lead-in area, a data area and an end-of-data (EOD) area. Each track comprises successive blocks or fragments of data, and each fragment has a compact header containing a synchronization byte, six information bytes and two parity bytes. The information bytes include a fragment ID, an area ID sub code identifying the area in which the fragment is located, and various other sub codes relating to logical structure of the data. The inclusion of an area ID sub code and logical structure sub codes in the (compact) header of every fragment facilitates reliable searching of the data stored on the tape at high tape advance speeds.

Abstract: A data storage device for reading and/or writing data to a storage medium includes a buffer memory (15) for smoothing the flow of data to/from the storage medium. Activation of the storage apparatus (9) to read/write data from/to the storage medium is generally controlled in dependence upon the amount of data held in the buffer (13). In order to optimize utilization of the buffer (15), it is proposed to adaptively set the threshold level at which such activation is effected. To this end, the utilization of the buffer (13) during a previous activation is monitored and a new threshold value is set in dependence on the monitored utilization parameter.