On-Line Data-Acquisition Systems in Nuclear Physics, 1969: Chapter 1 - THE TASKS

On-Line Data-Acquisition Systems in Nuclear Physics, 1969, by H. W. Fulbright et al. National Research Council is part of the HackerNoon Books Series. You can jump to any chapter in this book here. Chapter 1: THE TASKS

We first list the main uses to which on-line computer systems have been put. We start with the simple operations, which we call Class 1.

a. Accepting digital data from external devices and storing it in computer memory.

b. Preliminary processing of incoming data, on-line, before storage. This usually involves only operations of logic and simple arithmetic.

c. Controlling the presentation of data via cathode-ray oscilloscope or typewriter, often for the purpose of monitoring the progress of an experiment.

d. Controlling the recording of digital data on magnetic tape, paper tape, or other storage medium.

e. Controlling an incremental plotter.

f. Controlling the output of large quantities of data via a line printer.

g. Transmission of quantities of data between two computers or between a computer and a pulse-height analyzer or other device having a magnetic core memory.

Several operations of intermediate complexity we will label Class 2.

a. Processing of data already accumulated and stored either in memory or on tape or other medium (off-line processing). This data reduction is often more complicated and lengthy than the preliminary on-line processing referred to in (Class 1b).

b. Calculation of information required by the experimenter during the experiment, for example, kinematics tables and particle energies corresponding to field strengths in analyzer magnets.

c. Process-control operations, in which the computer directs or regulates a sequence of events in an experiment. Under program control the computer monitors the course of the experiment and supplies signals that cause automatic changes in experimental conditions, such as starting and stopping times of event counting, angles of observation of scattered particles, and accelerator energies. Such applications [Pg 3]are designed to relieve the experimenter of unnecessary labor and to reduce the probability of error in routine operations.

Our final class involves even more complex calculations.

a. Complicated treatment of reduced data, including least squares and curve fitting.

b. Large-scale calculations such as those required for the evaluation of theoretical nuclear scattering and reaction cross sections, e.g., DWBA calculations, which may each require running times of the order of minutes, even at a modern computing center.

Apparently Class 3 operations do not always have to be done during the course of the experiment; in fact, they can in most cases be carried out later, leisurely, at the local computing center. Nonetheless, calculations of the first type, and to a lesser extent the second, are currently being done at laboratories having large, powerful computers in their on-line data-acquisition systems.