The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 1995
Filed:
Nov. 03, 1992
James A Brewer, Leander, TX (US);
Paul R Habermehl, Round Rock, TX (US);
James M Stafford, Round Rock, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Simultaneous use of multiple expanded memory cards and their associated Expanded Memory Manager (EMM) device drivers in a computer system is provided. First, an expanded memory card is added and its EMM device driver will check to verify if another EMM driver is currently installed. If so, the new EMM device driver will take control of the existing EMM device driver in a master-slave relationship. The new EMM device driver (master) controls the existing EMM device driver (slave) by use of the slave's interrupt vector. That is, the master controls the slave by having an interrupt vector for the slave readdressed to be input to the master. Thereby, providing the master with the expanded memory interrupts the slave was required to service. The master also takes control of all the slave's handles and pages by appearing as a requesting program application to the slave. Another feature of the present invention will allow multiple EMM device drivers to be installed in an efficient manner, by eliminating code that is redundant between existing and newly added EMM device drivers.