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: A method of centralized data position information storage comprising the steps of arranging a byte stream of data into partitioned logical data, providing an updateable centralized storage area being operable to store data position information relating to the logical data, utilizing the information to locate a target data and storing the data position information in the storage area using a first algorithm applied to the target data to update the storage area with target data position information and using a second algorithm applied to a non-target data to update the storage area with non-target data position information such that data position information is accumulated in the centralized storage area when a target data is located and accessed.

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: A method of centralised data position information and storage and utilisation comprising the steps of arranging a byte stream of data into partitioned logical data, storing data position information relating to the logical data in a reserve storage area, transferring the information from the reserve storage area to a centralised storage area configured to store information relating to substantially all the partitioned logical data and utilising the information to locate a target data using a search algorithm.

Abstract: A tape is associated with a semiconductor memory storing the end position of the last data of a data set recorded on the tape. The end location is stored in the memory before the last data are written to the tape. In a further operation mode, data identifying the location of one or plural successfully written data sets which have already been written to the tape are stored in the memory while user data are written to the tape.

Abstract: A method of centralised data position information and storage and utilisation comprising the steps of arranging a byte stream of data into partitioned logical data, storing data position information relating to the logical data in a reserve storage area, transferring the information from the reserve storage area to a centralised storage area configured to store information relating to substantially all the partitioned logical data and utilising the information to locate a target data using a search algorithm.

Abstract: A method of centralized data position information storage comprising the steps of arranging a byte stream of data into partitioned logical data, providing an updateable centralized storage area being operable to store data position information relating to the logical data, utilizing the information to locate a target data and storing the data position information in the storage area using a first algorithm applied to the target data to update the storage area with target data position information and using a second algorithm applied to a non-target data to update the storage area with non-target data position information such that data position information is accumulated in the centralized storage area when a target data is located and accessed.

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.