Browse Prior Art Database

Use of System Extension Queue for Freemain (and Freecell),

IP.com Disclosure Number: IPCOM000052291D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Goldstein, BC: AUTHOR [+3]

Abstract

The following pictorial provides a simple view of how FREEMAIN works today. This is followed by a new approach. See Original

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Use of System Extension Queue for Freemain (and Freecell),

The following pictorial provides a simple view of how FREEMAIN works today. This is followed by a new approach. See Original

The new approach basically breaks the Freemain process between between the transitions from step (1) Invalidate ... to step (2) Get lock ...

When an application issues a Freemain on a virtual address range, then that range is immediately invalidated, the bookkeeping functions of updating control blocks, etc., to reflect this release of storage is queued for later processing, and control is returned to the applications.

The actual processing of this deferred Freemain queue is done either at:
1) TASK Termination
2) GETMAIN when no more virtual (private) is available
3) Page Fault on an invalidate page resulting from

step (1) of the FREEMAIN process
4) Not at all - in the event of a STARTed task/LOGON(TSO) memory

termination (i.e., any single job memory).

When the queue is to be processed, it is sorted by virtual address. Thus, actual processing now of the queue provides better recognition of contiguous free areas, reduced (total) time under the FREEMAIN lock (SALLOC), and fewer total instructions for processing FREEMAINS.

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