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# Tab Rack Data Reduction Algorithm

IP.com Disclosure Number: IPCOM000089639D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 47K

IBM

## Related People

Busch, DG: AUTHOR

## Abstract

Systems often have a discrete tab rack containing, for example, 200 possible tab stop locations. In the communications mode this information is sent using Operator Control Language (OCL). In many instances, these tab stops are set on systematic repetition counts (i.e., tab every 5 positions). An algorithm is provided which converts repetitive tab grids with counts from 1 to 12 to the appropriate OCL instruction. This provides a reduction in the amount of data to be transmitted in certain cases from, for example, 400 characters to only 6 or 7 characters.

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Tab Rack Data Reduction Algorithm

Systems often have a discrete tab rack containing, for example, 200 possible tab stop locations. In the communications mode this information is sent using Operator Control Language (OCL). In many instances, these tab stops are set on systematic repetition counts (i.e., tab every 5 positions). An algorithm is provided which converts repetitive tab grids with counts from 1 to 12 to the appropriate OCL instruction. This provides a reduction in the amount of data to be transmitted in certain cases from, for example, 400 characters to only 6 or 7 characters.

For a typical TAB the OCL instruction may be as follows: TABS X(1) [X(2)[X(3)...]].

This means that tab stops are to be set with respect to the margin scale of the input keyboard at scale values X(1), X(2),... from the left edge. If only one operand X is specified and its value is between 1 and 12, then a tab grid is to be set with intervals of X relative to the left margin. 1 </= X(1) < X(2) < X(3)... < X(n)...

Further, if only a single operand X = 0 is specified, an error message results, and machine standard error recovery routines are initiated. To set a single tab stop at a position </= 12, the position is specified by repeating the tab setting, e.g., TABS 5 5 would set a single tab at 5. To clear a tab rack, a tab setting of 0 is specified twice, e.g., TABS 0 0.

If all operands are omitted, the instruction is ignored, and the active tab stops are used.

In the present techniq...