Browse Prior Art Database

Fast Local Subpicture Generation for Raster Displays

IP.com Disclosure Number: IPCOM000080500D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Bantz, DF: AUTHOR

Abstract

A local command memory is used to store frequently used subpicture presentations which, due to their complexity, could not be stored in the conventional raster display memory.

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Fast Local Subpicture Generation for Raster Displays

A local command memory is used to store frequently used subpicture presentations which, due to their complexity, could not be stored in the conventional raster display memory.

Customarily it is the practice to store common subpicture bit patterns in a memory located within the display unit, from which they can be copied into the refresh buffer as needed. Due to the limited storage capacity of the display memory, a maximum size such as 5 X 7 or 7 X 9 points is imposed upon the subpicture matrix, thereby severely limiting the complexity of subpictures which can be usefully held in local storage. For those pictures which cannot be locally stored, the computer emits graphic orders which absorb an undesirable amount of the I/O bus capacity.

It is proposed+ herein to provide a command memory separate from the display memory, for locally storing graphic orders that represent subpictures likely to be used repetitively. With such an arrangement, the subpicture matrix need not be limited to a small size. When a new subpicture is to be stored, the switch S1 is set to its dotted-line position. Storing begins when the interface receives a "Store Subpicture" order from the computer. This order specifies a starting address to which the command memory address register is initialized. As subsequent commands are entered into the command memory, the memory address register is incremented. When the command "End Subpicture" is received and entered, storing ceases and S1 is reset. The command memory may be an unused p...