Multiple processor system having software for selecting shared cache entries of an associated castout class for transfer to a DASD with one I/O operation

摘要

A high-speed cache is shared by a plurality of independently-operating data systems in a multi-system data sharing complex. Each data system has access both to the high-speed cache and the lower-speed, secondary storage for obtaining and storing data. Management logic and the high-speed cache assures that a block of data obtained form the cache for entry into the secondary storage will be consistent with the version of the block of data in the shared cache with non-blocking serialization allowing access to a changed version in the cache while castout is being performed. Castout classes are provided to facilitate efficient movement from the shared cache to DASD.