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Printer Throughput Enhancements

IP.com Disclosure Number: IPCOM000051713D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Smith, BA: AUTHOR [+2]

Abstract

One type of matrix printer contains a single 256-byte circular print an receive buffer. As each character is received, it is loaded into the buffer in ascending order. Printing does not occur until an entire line (up to 198 characters) and a delimiter (forms feed, etc.) has been received and processed. A problem arises when a series of print lines are received each of which is greater than 100 characters, since only one complete line can reside in the buffer at any time due to the limited buffer size and a requirement that certain overhead data such as header information and command information, also will be included. When the situation of several hundred or more character lines to be printed does occur, the printer must remain idle after printing each line until the next complete line has been loaded into the buffer.

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Printer Throughput Enhancements

One type of matrix printer contains a single 256-byte circular print an receive buffer. As each character is received, it is loaded into the buffer in ascending order. Printing does not occur until an entire line (up to 198 characters) and a delimiter (forms feed, etc.) has been received and processed. A problem arises when a series of print lines are received each of which is greater than 100 characters, since only one complete line can reside in the buffer at any time due to the limited buffer size and a requirement that certain overhead data such as header information and command information, also will be included. When the situation of several hundred or more character lines to be printed does occur, the printer must remain idle after printing each line until the next complete line has been loaded into the buffer. This idle time can be quite substantial when several 198-character lines are being printed in succession.

In order to improve the throughput, two enhancements are made to the buffer handler software routines. First, the buffer is backfilled while printing instead of waiting until a line has been printed to fill in the vacated buffer space. While doing this, the pointers are updated after every character is read to allow information to be loaded into the buffer as data is being printed. This improves the turnaround on the right side because when characters are printed from left to right, the data is read into and out o...