An information processing system includes a central processing unit, a main storage, a main storage controller for controlling the main storage, a cache memory having a content of at least one part of addresses stored in the main storage, at least one DMA controller which is capable of ...http://www.google.com/patents/US5749093?utm_source=gb-gplus-sharePatent US5749093 - Enhanced information processing system using cache memory indication during DMA accessing 
