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Browse Prior Art Database

Host Notification of Subsystem Or Device Status Change

IP.com Disclosure Number: IPCOM000100383D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Crockett, RN: AUTHOR [+6]

Abstract

An expanded pack change interrupt is disclosed which permits a host to maintain control blocks storing current status and configuration information regarding DASD subsystems and attached devices. New storage controls 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 host can obtain the required knowledge by performing I/O to the subsystems to determine their current status and configuration. The problem thus presented and herein solved is how to provide the necessary information to the host operating system without requiring undue amounts of I/O between the host and the attached subsystems.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 74% of the total text.

Host Notification of Subsystem Or Device Status Change

       An expanded pack change interrupt is disclosed which
permits a host to maintain control blocks storing current status and
configuration information regarding DASD subsystems and attached
devices.  New storage controls 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 host can obtain the
required knowledge by performing I/O to the subsystems to determine
their current status and configuration.  The problem thus presented
and herein solved is how to provide the necessary information to the
host operating system without requiring undue amounts of I/O between
the host and the attached subsystems.

      The aforementioned problem is solved by an expanded pack change
interrupt.  A pack change interrupt indicates the possibility that
the volume status of a subsystem or device may have changed.  The
pack change interrupt is expanded to allow a storage control to
notify the attached hosts whenever a status change occurs in either
the subsystem or its attached devices.  The hosts can thus maintain
control blocks storing current status and configuration information,
thereby preventing the need for I/O to a subsystem every time
device/subsystem status information is required by t...