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Parallel Tasking of Display Formatting and Character Image Retrieval

IP.com Disclosure Number: IPCOM000042522D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Aiken, JA: AUTHOR [+4]

Abstract

Disclosed is a method for simultaneously running two processes of display formatting and character image retrieval in a word processing system, which enables to substantially decrease the display update's WAIT period. A common problem faced by office machines implementing an ideographic character set (Kanji) is the large amount of storage required to hold the character images for the display. A typical implementation of a language, such as Japanese, might require the availability of several thousand different characters; each of which has a complexity requiring 24 by 24 bit resolution for satisfactory legibility.

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Parallel Tasking of Display Formatting and Character Image Retrieval

Disclosed is a method for simultaneously running two processes of display formatting and character image retrieval in a word processing system, which enables to substantially decrease the display update's WAIT period. A common problem faced by office machines implementing an ideographic character set (Kanji) is the large amount of storage required to hold the character images for the display. A typical implementation of a language, such as Japanese, might require the availability of several thousand different characters; each of which has a complexity requiring 24 by 24 bit resolution for satisfactory legibility. One alternative for managing this quantity of data is to maintain the most commonly used character images in a semiconductor memory and paging the infrequently used characters into the memory as they are needed from magnetic media storage, such as a floppy disk or a small disk file. Display formatting in these situations involves: 1. Converting the internal word processing data stream into the appropriate image of the final printed page. This process is completely dependent on the CPU with no I/O operations required. 2. Managing the character image database and retrieving characters not present in the memory when required. This process requires much more time for I/O from the magnetic media storage than CPU time. By running these two processes simultaneously, two benefits are achieved: 1. The total amount of time needed to create an image for the display is reduced. 2. Display update appears to be much smoother to the operator. If the display formatting waits for character retrieval, the display appears to be updated in bursts; a burst of formatting followed by a short delay for character image access followed again by another burst of formatting. The following is a brief description of a specific implementation of this technique in a Japanese word processing system. This system is assumed to be a task driven machine, wherein work requests of processes with varying priorities may be made. When processes of higher priority have completed or entered a WAIT state, lower priority processes will be given control of the machine. For example, a process requesting a magnetic media storage operation will enter into the WAIT state when the request is made, since the storage cannot respond too instantl...