System and method for caching information in a digital data storage subsystem

摘要

A digital data storage subsystem stores data for use by digital data utilization device. The data as used by the digital data utilization device being organized in the form of variable-length records. The digital data storage subsystem includes a digital data storage device, a cache and a cache control. The digital data storage device has at least one fixed block storage unit for storing a predetermined amount of data, the storage unit storing at least one record and additional padding if the record does not comprise at least said predetermined amount of data. The cache including at least one cache slot which can accommodate the storage of the predetermined amount of data, that is, the amount which can be stored on the block storage unit of the digital data storage device. The cache control controls the transfer of data from the fixed block storage unit to the cache slot for use by the digital data utilization device, and in addition controls the transfer of data from the cache slot to the fixed block storage unit if the digital data utilization device modifies the data in the cache slot. The cache control controls the transfer so that the format of the data in the fixed block storage unit conforms to the format of the data in the cache slot, so that no changes are required to the formatting of the data during such a transfer.