International Business Machines Corporation

John H Christian

David G Reed

Arthur H Nolta

Richard E Rieck

Michael Howard Hartung

Gerald E Tayler

John S Williams

James L Overacker

Rolf Andresen

John S William

Terrell N Truan

Data is promoted from a backing store (disk storage apparatus termed DASD) to a random access cache in a peripheral data storage system. When a sequential access bit is sent to the storage system, all data specified in a read 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, up to a predetermined maximum, not yet read to be promoted to cache.

Method and system for handling sequential data in a hierarchical store

A plurality of addressable data storage devices are selectively directly accessed or accessed via a cache memory. Access via the cache memory uses one of a plurality of logical addresses; each of the data storage devices is represented by a plurality of the logical addresses. Each of the data storage devices can be reserved for direct access; such reservation does not apply to device accesses via the cache. Accesses to the devices are queued on a device basis.

Method and apparatus for a hierarchical paging storage system

Direct access storage devices (DASD) are connected to a host via a cache. Each device can be independently addressed by any one of a plurality of addresses, also termed logical devices and exposures. Since operations between DASD and cache are combined for all of the independent logical devices, resetting operations related to one independent logical device can inadvertently interfere with operations of another independent logical device. To maintain data integrity, a programmed control accommodates logical device independence by using queues and control blocks relating to the DASD and logical devices, respectively.

Methods and apparatus for resetting peripheral devices addressable as a

A disk file employs a disk having sectors of track-following servo information interspersed around the disk between data portions. Included in each sector is a SYNC signal which is encoded to indicate the validity or invalidity of the servo information in that sector. The servo information in a sector is used only if the SYNC signal indicates that it is valid.

Sector servo with sync marks

Utilization of production equipment with diverse throughput rates is optimized by a central random access article storage apparatus disposed centrally of peripherally positioned production equipment. Computer controls enable fully automatic sequencing of production flow. The storage apparatus provide transient storage and article queuing during intermediate successive production steps. The computer control enables automatic article tracking for quality control as well as diagnosis of automatic production equipment problems.

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Tucson, AZ, United States of America

John H Christian