Branched Data Promotion
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
In a cached DASD (direct access storage device) storage system upon an attempt to read-access miss for "count Key data" (CKD) home address (RHA) or seek involved with a read data (RD SEEK). The data is accessed from DASD and supplied to the requesting host processor and is simultaneously stored in the cache. Otherwise, on other read misses, data is first promoted to cache and then transferred to the host processor. In implementing branch data promotion, every field encountered in reading data from DASD to the requesting host processor is stored in the cache irrespective of whether the requesting host processor requested the intervening records. In transferring data to the host processor, the unrequested fields or records are not supplied to the host and yet are stored in the cache.