Cache control system

A data storage system for fulfilling read and write requests from a computer comprising:

• a solid-state cache memory;
• a storage element with at least one moving part wherein the storage element has an operating, and a non fully operating mode when data access has not occurred for a predetermined time period;
• a cache control system responsive to read and write requests from the computer, said cache control system further comprising,
• means to access data stored on the storage element if a read or write request cannot be satisfied via access to the cache memory;
• means for accessing data stored within the cache memory if a read or write request from the computer can be satisfied via access to the cache memory;
• means for designating selected data within said cache memory as new data in response to a write request from the computer which updates data within the cache memory;
• and
• a cache replacement mechanism for transferring new data from the cache memory to the storage element to maintain consistency of data between data stored in the cache memory and data stored in the storage element, wherein the cache replacement mechanism performs data transfers between the cache memory and the storage element when the storage element is at operating speed as a result of a read or write request which requires an access to the storage element.