An instrument that isn't really [Laboratory Virtual InstrumentEngineering Workbench]

The concept and development of LabVIEW (Laboratory Virtual Instrument Engineering Workbench), a virtual instrument (VI) that provides a simple, graphical way to set up and run numerous instruments on a Mackintosh PC, are described. The first concept basic to LabVIEW had its roots in a large test system comprised of programmable signal sources compatible with IEEE-488 interface specifications, and switching matrices and measurement instruments controlled by a minicomputer. The test system's strength was its flexibility, which it owed to its several levels of user interfaces. This flexible configuration was refined into the notion of instrumentation as a hierarchy of virtual instruments in which all VIs at all levels had the same type of construction. Another characteristic was that each VI have its own user interface. The final conceptual element was the use of loop data-flow structures as the technique used by an engineer to construct and run his or her own VIs. Problems encountered in the development of LabVIEW and the solutions used are discussed