Abstract: A storage hierarchy has a caching buffer and a backing store; the backing store preferably having disk-type data-storage apparatus. A directory indicates data stored in the caching buffer. Upon a data-storage access, read or write, within a series of such accesses, resulting in a cache miss, all subsequent data storage accesses in the series are made to the backing store to the exclusion of the caching buffer even though the caching buffer has storage space allocated for such a data transfer. Selected limits are placed on the series to the backing store, such as receiving on end of series (end of command chain) indication from a using unit, crossing DASD cylinder boundaries, receiving an out of bounds address or receiving certain device oriented commands.

Abstract: In a storage hierarchy, promotion of data from a backing store to a caching buffer store is restricted based upon status of the cache and activity of a last storage reference. Observed writing activity selectively inhibits data promotion. Data promotion occurs after completion of a series of storage access requests. A peripheral data storage system is described.