Browse Prior Art Database

A Method and Apparatus for Non-disruptive Device Level Quiesce

IP.com Disclosure Number: IPCOM000110202D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 1 page(s) / 57K

Publishing Venue

IBM

Related People

Cook, TE: AUTHOR [+2]

Abstract

Situations arise in computing environments where there is a need to stop activity to a peripheral device without removing the device from service or canceling the jobs using the device. In the past, the entire system needed to be quiesced. This disclosure provides a method and mechanism for performing a non-disruptive device level quiesce without quiescing the entire system.

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This is the abbreviated version, containing approximately 64% of the total text.

A Method and Apparatus for Non-disruptive Device Level Quiesce

      Situations arise in computing environments where there is a
need to stop activity to a peripheral device without removing the
device from service or canceling the jobs using the device.  In the
past, the entire system needed to be quiesced.  This disclosure
provides a method and mechanism for performing a non-disruptive
device level quiesce without quiescing the entire system.

      The disclosed method is based on an operator-entered command or
an automated signal which is given to a system.  The command or
signal will trigger the system program to artificially raise the
minimum priority of I/O requests allowed to be started by software to
a level above the normal level.  The priority of the I/O requests
themselves is not altered.  The minimum priority a request must have
to be started is raised above the maximum level a non-system I/O
request can have.  This prohibits normal I/O and allows only system
control program-related I/O to be initiated.  The priority of queued
I/O requests would remain at the normal level.  The net effect is
that all queued I/O requests remain queued because the priority
required to get started has been artificially raised to a higher than
normal level.

      The command or signal is accepted for a device only if the
device is in a safe state.  A safe state means that the device is not
currently reserved to the system quiescing it and it is not a system
vo...