Browse Prior Art Database

Managing Data Storage Systems

IP.com Disclosure Number: IPCOM000059854D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Carlson, SM: AUTHOR [+3]

Abstract

Path activity indicators are used for managing concurrently executing processes which operate a data storage hierarchy. Path activity indicators indicate the activities of paths emanating from a cache which then extend to various portions of the various subsystems. Each path can have a process operating on it for transferring data to any user, a backing store and the cache. Backing store polling is inhibited when a path to any of the devices is active.

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Managing Data Storage Systems

Path activity indicators are used for managing concurrently executing processes which operate a data storage hierarchy. Path activity indicators indicate the activities of paths emanating from a cache which then extend to various portions of the various subsystems. Each path can have a process operating on it for transferring data to any user, a backing store and the cache. Backing store polling is inhibited when a path to any of the devices is active.

The storage hierarchy consists of a cache module and a device module. These modules contain programming for respectively operating a cache and a device. An interchange of control information between the two modules is effected through a vintage sensoring unit called BML, wherein the microprocessor indicators are stored by a SAVE function S and restored by a RESTORE function R to the respective modules. In this manner, execution of the modules is interleaved. Error recovery by the respective modules is based upon the path activity indicators (PAI) contained in a register based upon a scanning mechanism of the subsystem. The scanning mechanism can either be the idle scan routine or a hardware scan. The scanning mechanism scans the three paths P1, P2 and P3 and updates PAI. If any of the paths are inactive, then a process can be assigned to the path for transferring data between the cache, a user (host processor, for example) or a device. If a path is not active with a device, then the sc...