Multi-system data sharing combination and method of operating same

摘要

A high-speed cache 16 is shared by a plurality of independently-operating data systems 10,11, 12 in a multi-system data sharing complex. Each data system has access both to the high-speed cache 16 and to lower-speed, upper-level storage 14,15 for obtaining and storing data. Management logic 17 in the high-speed cache 16 ensures that a block of data entered into the cache will not be overwritten by an earlier version of the page obtained from the upper-level storage.