Browse Prior Art Database

Dual-Screen Image Buffer Method for Display State Tracking

IP.com Disclosure Number: IPCOM000112721D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Boegel, MA: AUTHOR [+3]

Abstract

A dual-screen image buffer method for keeping track of the display state for a Non-Programmable Terminal (NPT) is disclosed. This method allows a Work Station Controller (WSC) to determine the device state according to actual transmitted data when Direct Memory Access (DMA) buffering is utilized.

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Dual-Screen Image Buffer Method for Display State Tracking

                                        Commands
                                          From Host
                                              |
                                              |
   +--------------------------------------------------------+
   | WSC                                      |             |
   |                                          V             |
   |  +-----------------+  Host      +------------------+   |
   |  |                 |  Commands  |                  |   |
   |  | Host Command    |     +      |  Working Copy    |   |
   |  | Storage Queue   |  Xmit DMA  |  of Display      |   |
   |  |                 |  location  |  State Buffer    |   |
   |  |                 |<-----------|                  |   |
   |  |                 |            |                  |   |
   |  +-----------------+            +------------------+   |
   |           |                              |             |
   |     Host  Commands                Display Commands     |
   |           |                              |             |
   |           V                              V             |
   |  +------------------+           +------------------+   |
   |  |                  |           |                  |   |
   |  | Actual Display   |           | Transmit DMA     |   |
   |  | State Buffer     |           |                  |   |
   |  |                  |           |                  |   |
   |  +------------------+           +------------------+   |
   |                                          |             |
   +--------------------------------------------------------+
                                              |
                                       Display Commands
                                              |
                                              V
          ...