Reading Data from Instruments

• A common measurement setup is that a computer controlling an experiment collects data from an instrumentation bus for as long as it takes.
• It may not be possible to predict a priori how much data will be collected. The program must keep allocating memory dynamically as the data flows in.
• This is very similar to reading data from a file of no predetermined length. IEEE-488 and other devices are often represented by device files in the /dev directory.
• A program may have to buffer the data and when the buffers get full, it must release the data onto a file, clean the buffers, and resume data collection. This requires sophisticated hand-shaking with the measuring apparatus.
• The following program illustrates the basic methodologies employed in such measurements - minus the hand-shaking bit.