公开(公告)号：DE3751474D1

公开(公告)日：1995-09-28

申请号：DE3751474

申请日：1987-02-05

Applicant: IBM

Inventor： EMMA PHILIP GEORGE ,  POMERENE JAMES HERBERT ,  PUZAK THOMAS ROBERTS ,  RECHTSCHAFFEN RUDOLPH NATHAN ,  SPARACIO FRANK JOHN

IPC: G06F9/38

公开(公告)号：DE3586635D1

公开(公告)日：1992-10-22

申请号：DE3586635

申请日：1985-02-28

Applicant: IBM

Inventor： POMERENE JAMES HERBERT ,  PUZAK THOMAS ROBERTS ,  RECHTSCHAFFEN RUDOLPH NATHAN ,  SPARACIO FRANK JOHN

IPC: G06F12/08

Abstract: An efficient prefetching mechanism is disclosed for a system comprising a cache. In addition to the normal cache directory (11), a two-level shadow directory (13, 15) is provided. When an information block is accessed, a parent identifer (P) derived from the block address is stored in the top level (13) of the shadow directory. The address of a subsequently accessed block (Q) is stored in the second level (15) of the shadow directory, in a position associated with the first-level position of the respective parent identifier. … With each access to an information block, a check is made whether the respective parent identifier (P) is already stored in the first level of the shadow directory. If it is found, then the descendant address (Q) from the associated second-level position is used to prefetch an information block to the cache if it is not already resident therein. This mechanism avoids with high probability the occurence of cache misses.