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:
May. 23, 1989
Filed:
Mar. 23, 1988
Patrick A Buckland, Austin, TX (US);
John W Irwin, Georgetown, TX (US);
Jack E Reeder, Round Rock, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and system for controlling the display of data in a data processing system that includes a main processor, a memory subsystem, and an Input/Output subsystem which includes an I/O Channel Controller for managing traffic on an I/O bus having an attached co-processor and a plurality of I/O devices including display devices with different reserved I/O address space. The main processor can establish different display modes for displays having different reserved I/O address space, which generally indicates different display types. In one mode, a display is assigned exclusively to the main processor and attempted data transfers by the co-processor to that display are suppressed. In a second mode, a display is time-shared between processors by establishing a virtual video buffer in main memory which is written into by one processor when the other processor has control of the display device. The contents of the virtual and real buffer are swapped whenever the display is reassigned to the other processor. In the third mode, co-processor data in the virtual buffer can be 'windowed' onto the display device when it is assigned to the main processor. In the fourth mode, a display assigned to the co-processor displays data being run by code that is written to the displayed on a display device with a different pel resolution. The main processor does a pel conversion operation on the data in the process of transferring the data from the virtual buffer to the real buffer.