Browse Prior Art Database

Shared Resource Locking Controls

IP.com Disclosure Number: IPCOM000050917D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 35K

Publishing Venue

IBM

Related People

Wagner, RE: AUTHOR

Abstract

It is desired to synchronize input/output operations directed to a shared peripheral unit, such as a direct-access storage device (DASD), in a multiple host processor environment in a more efficient manner in terms of the number of accesses and the level of granularity than the RESERVE/RELEASE of the individual data storage unit. With peripheral data storage units having greater and greater data storage capacities, access to shared control data sets, such as catalogs, is becoming more critical in terms of overall system performance. Accordingly, it is desired to lock and unlock subunits (addressable storage areas) of a data storage apparatus in a simple and efficient manner.

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Shared Resource Locking Controls

It is desired to synchronize input/output operations directed to a shared peripheral unit, such as a direct-access storage device (DASD), in a multiple host processor environment in a more efficient manner in terms of the number of accesses and the level of granularity than the RESERVE/RELEASE of the individual data storage unit. With peripheral data storage units having greater and greater data storage capacities, access to shared control data sets, such as catalogs, is becoming more critical in terms of overall system performance. Accordingly, it is desired to lock and unlock subunits (addressable storage areas) of a data storage apparatus in a simple and efficient manner.

The proposed solution is composed of a process across two elements. The first element is a logical lock which can be associated with a set of tracks, cylinders, or other convenient physical or logical construction of the storage apparatus independent from the physical geometries, the plurality of data sets or a resource separate from the data storage device storing the lock. The second element is a set of structural information which is associated with the logical lock. This data is maintained by the users of the lock and is composed of data which allows users to minimize control block changes and buffer invalidation for the entity being shared. The process maintains a queue of locks of interest, the status of these locks, the data of interest associated with these locks, and the management thereof. The processing mechanism and the queues of locks may reside in a separate special-purpose processor to further enhance the performance of the function.

The figure shows a plurality of users, which may be a computer process within a single host or a plurality of host processors, several communications links, and the like. A common attribute of the users is that they access a common set of data stored on one or more data storage devices. As shown, there are three locks which respectively control shared access to three different resources. The lock entity resides in some convenient storage medium common to all users of the facility and contains an identifier, the status of the lock, associated structural data such as levels of index and numbers of...