Browse Prior Art Database

Expanded Memory Manager Chained Slave Performance Increase Technique

IP.com Disclosure Number: IPCOM000106033D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Brewer, JA: AUTHOR [+3]

Abstract

Disclosed is a method to improve performance of an Expanded Memory Manager (EMM) slaved device driver. The configuration consists of two EMM device drivers, where the first driver is installed as the slave and the second driver is the master. The master EMM driver is seen by the slave as its "sole" application (that is, the master driver acts as an application to request and receive all appropriate resources of the slave driver). The master also uses a "Fast Tables Structure" which allows it to quickly access EMM pages. The slave uses a slower linked-list type of structure to access its' EMM pages.

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This is the abbreviated version, containing approximately 52% of the total text.

Expanded Memory Manager Chained Slave Performance Increase Technique

      Disclosed is a method to improve performance of an Expanded
Memory Manager (EMM) slaved device driver.  The configuration
consists of two EMM device drivers, where the first driver is
installed as the slave and the second driver is the master.  The
master EMM driver is seen by the slave as its "sole" application
(that is, the master driver acts as an application to request and
receive all appropriate resources of the slave driver).  The master
also uses a "Fast Tables Structure" which allows it to quickly access
EMM pages.  The slave uses a slower linked-list type of structure to
access its' EMM pages.

      When the master driver installs in the system, it steals the
slave's interrupt vector and replaces it with it's own.  The master
allocates all of the slaves' handles and obtains the maximum count of
pages available.  The master will split the number of available slave
pages among the slave's handles, requesting and receiving an
appropriate number of pages for each handle.  The slave's pages,
referenced by the slave's handles are entered into the master
driver's unallocated pages list.  When the master driver maps or
unmaps any page associated with the slave driver, it references it
with the appropriate slave's handle and slave EMM logical page.
Because the number of pages which are entered into any linked-list of
the slave are limited, the slave will on average, spend less time
searching it's l...