Browse Prior Art Database

Multiterminal Data Recording Without Terminal Buffers

IP.com Disclosure Number: IPCOM000080795D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Buckley, JF: AUTHOR

Abstract

When remote terminals such as terminals 11 of the figure communicate with a computer, there may be instances when the communication line to the computer becomes inoperative. Under those circumstances, it is desirable to provide data capture capability such as provided by data capture unit 15. When the communication line to the CPU is restored, data captured by data capture unit 15 can then be batch transmitted to the CPU.

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Multiterminal Data Recording Without Terminal Buffers

When remote terminals such as terminals 11 of the figure communicate with a computer, there may be instances when the communication line to the computer becomes inoperative. Under those circumstances, it is desirable to provide data capture capability such as provided by data capture unit 15. When the communication line to the CPU is restored, data captured by data capture unit 15 can then be batch transmitted to the CPU.

The normal method of capturing data from a terminal is to accumulate the data bytes of each terminal, in an individual terminal buffer as a complete record before recording. This method requires a hardware buffer for each terminal. The data capture unit 15 eliminates the need for individual buffers by preceding each data byte with an ID byte received from the multiplex counter 131 of multiplex unit 13, which identifies the terminal from which the data byte originated. The ID byte may be any nondata pattern and if the data capture or disk format allows, an extra ID bit position may be defined. For example, if 8-bit data bytes are used, a 9th bit position may be the parity check bit and a 10th bit position may be the ID bit position.

The data capture unit operates as follows. As the multiplex counter 131 of multiplexer 13 continuously increments from 1 through N, it activates multiplex switch driver 133 to connect the output data byte from each terminal 11 to data bus 135 by multiplex switch 137. As each terminal 11 is connected to data bus 135, a data byt...