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Browse Prior Art Database

Host-Subsystem Control Block Structure

IP.com Disclosure Number: IPCOM000100382D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Crockett, RN: AUTHOR [+6]

Abstract

A host-subsystem control block structure is disclosed which ensures that readers of subsystem control blocks receive current information. A storage control may contain features associated with where data is stored on DASD, as well as performance features affecting the data's writing and retrieval. A host operating system requires knowledge of these features in making decisions as to the proper placement of, and access to, data sets. The knowledge of the host operating system must therefore be accurate at the time the decision of the host is made (i.e., current). The problem thus presented and herein solved is how to ensure that a reader of a specific subsystem control block receives current subsystem/device status information.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 71% of the total text.

Host-Subsystem Control Block Structure

       A host-subsystem control block structure is disclosed
which ensures that readers of subsystem control blocks receive
current information.  A storage control may contain features
associated with where data is stored on DASD, as well as performance
features affecting the data's writing and retrieval.  A host
operating system requires knowledge of these features in making
decisions as to the proper placement of, and access to, data sets.
The knowledge of the host operating system must therefore be accurate
at the time the decision of the host is made (i.e., current).  The
problem thus presented and herein solved is how to ensure that a
reader of a specific subsystem control block receives current
subsystem/device status information.

      The aforementioned problem is solved by a set of subsystem
control blocks which are dynamically updated to contain status and
configuration information for their respective subsystems.  The
attached hosts can access the information stored in the control
blocks to determine the existing storage control features.
Synchronization of the information used in host decision making
processes and the information stored in the control blocks is ensured
by centralizing access to the control blocks via a common host
service.  A host operating system can thus make decisions across
storage controls, subsystems within storage controls, and devices
within subsystems.

      In addition to permi...