Data flow control in an online system

Abstract

Valuable computer time and memory space is saved by using a microprocessor (Mostek F8) to control the flow of data in a multichannel laboratory data collection system. Special digital converters transmit serial BCD signals with added control bits. The F8 is used to translate the BCD to binary, reject unwanted data, and provide buffer storage. Full buffers of 128 bytes cause their contents to be transmitted to a DEC LSI11 installation for writing to its floppydisc in 64-word arrays. Should several buffers become full nearly simultaneously, additional ones are made available until all are cleared. This is done on a priority basis such that those carrying end of run signals are sent first, allowing the computer to proceed with further processing. The microprocessor program is held on disc files and is loaded into the F8 by a simple computer program together with some additional constants that are given by the operator during a question and answer sequence. The extra versatility this gives is enhanced by the resulting ability to make considerable program changes without having to change a PROM, which needs to hold only a bootstrap.