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公开(公告)号：CA1176382A
公开(公告)日：1984-10-16
申请号：CA406369
申请日：1982-06-30
Applicant: IBM
Inventor： CHRISTIAN JOHN H , HARTUNG MICHAEL H , NOLTA ARTHUR H , REED DAVID G , RIECK RICHARD E , WILLIAMS JOHN S
Abstract: The disclosure relates to promotion of data from a backing store (disk storage apparatus termed DASD) to a random access cache in a storage system such as used for swap and paging data transfers. When a sequential access bit is sent to the storage system, all data specified in a read "paging mode" command is fetched to the cache from DASD. If such prefetched data is replaced from cache and the sequential bit is on, a subsequent host access request for such data causes all related data not yet read to be promoted to cache. For a certain implementation, a maximal amount of related data is promoted; such maximal amount is determined by cache addressing characteristics and DASD access delay boundaries. Without the sequential bit on, only the addressed data block is promoted to cache. TU981014
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公开(公告)号：CA1197021A
公开(公告)日：1985-11-19
申请号：CA435244
申请日：1983-08-24
Applicant: IBM
Inventor： HARTUNG MICHAEL H , NOLTA ARTHUR H , REED DAVID G
Abstract: A so-called "roll mode" technique provides block transfer with a disk-type of direct-access data-storage device (DASD). A set of chained commands for accessing record areas enables rapidly accessing a plurality of records within a given DASD cylinder of tracks. The rotational position of the surfaces is checked. The command within the chain, irrespective of its location, having the closest logical rotational proximity to the instant rotational position of the surfaces is selected as the first command in the chain. The chain is executed beginning at the indicated rotational position selected command through the end of the chain and then wrapped to the beginning of the original chain and continuing o until the command immediately preceding the rotational position selected command has been executed.
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