Browse Prior Art Database

Quiesce and Idle of a System

IP.com Disclosure Number: IPCOM000048442D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Annunziata, EJ: AUTHOR [+3]

Abstract

This mechanism is used to quiesce and idle a system with a system controller that connects with all other elements of the system. The mechanism ensures that no data transfers are taking place.

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Quiesce and Idle of a System

This mechanism is used to quiesce and idle a system with a system controller that connects with all other elements of the system. The mechanism ensures that no data transfers are taking place.

"Quiesce" is a function that assures that no data transfer is taking place in the system. This state is required for the case where clocks are to be stopped, for example, error recovery where clocks are stopped and data is scanned, and normal clock-stop for displaying or altering the system. If clocks are arbitrarily stopped, data transfers may or may not be complete, resulting in questionable data integrity and/or additional error conditions.

Quiesce requires the ability to complete storage operations that are underway, but not accept any new operations; those which are waiting remain waiting.

In a system with a System Controller (SC), e priority mechanism (Q Array) can hold storage requests that are outstanding, waiting for a storage module to become available.

Quiesce (a) prevents all external service requests to the System Controller from competing on the SC's priority network, (b) allows, all operations underway to continue to their normal completion, and (c) allows commands waiting in the queue to be executed. Those commands that cannot be executed because they are waiting for castout or invalidate directory entry will exit when normal operation resumes and the conditions are satisfied.

"Idle" is a function that assures the system is not t...