On-Line Data-Acquisition Systems in Nuclear Physics, 1969

by National Research Council . Ad Hoc Panel on On-line Computers in Nuclear Research

1. How much large-scale computing is anticipated?

2. How much waiting time for results is tolerable?

3. Can the local computing center handle the needs, and at what cost?

4. If the local computing center can handle all the needs, but only after acquiring certain additional support for equipment or manpower, might not the better course of action be to provide that support rather than to set up separate facilities?

5. Can setting up a large system truly be justified? Have all the extra costs and complexities of the large system been taken into account, including those associated with input and output devices, operation, maintenance, programming, management, and space?

C. EXERCISING ECONOMIC JUDGMENT IN PLANNING

Since the ultimate criterion is research output, the role assigned to a computer system must depend on the nature of the work being planned. In some cases where a very specific use is intended, for example, in the case of a process-control application such as the Argonne plate scanner or an accelerator controller, the conditions are simple enough to make economic judgment relatively easy to apply. In the case encountered in setting up an accelerator laboratory where a wide variety of experiments is to be performed, conditions are much more complex. It is now widely accepted that any such laboratory should have a computer system, but what is not so clear is how extensive and expensive it should be. In other words, points 1-4 in B are accepted, and point 5 is conceded possibly to be applicable.

If sufficient funds are available, one sensible way to proceed is to use the accumulated collective experience outlined above. For example, one can say that experience has shown that the total investment in the computer system will be in reasonable balance with the capital investment in the bare accelerator if the ratio of costs is about one to five. Departures from the rule may then be made to adjust to special circumstances. Following this procedure means extrapolating from past experience, which may not prove a good guide, but this approach is similar to that often used in other matters bearing on the support of research. Probability is involved. It should be noted that the actual expenditures for on-line equipment for nuclear research have far exceeded those projected at the "Grossinger Conference on the Utilization of Multiparameter Analyzers in Nuclear Physics" in 1962.

In times of economic stringency it may be necessary to take a hard look at points 3-5 in B above before deciding how large a computer can be justified. A medium-sized computer is sufficient for most data-acquisition demands but not for large-scale calculations of a theoretical nature or for an occasional complicated piece of data reduction. Often it will be advisable to plan on carrying out all large calculations at the computing center, in which case a medium-sized computer will probably suffice for data acquisition, and a saving of about half in capital investment and operating expenses can be achieved.