1.1 THE RISE OF THE LABORATORY COMPUTER

Computers first started to be used in the laboratory about 45 years ago, about 10 years after the first digital computer, the ENIAC (Electronic Numerical Integrator And Calculator), had gone into operation at the University of Pennsylvania. Initially, these machines were very large, room-size devices, seen exclusively as calculating machines. However, by the mid-1950s laboratory applications were becoming conceivable. Interestingly enough, the earliest of these applications was in the physiological (or at least psychophysiological) field. The Whirlwind system developed by Kenneth Olsen and others at Massachusetts Institute of Technology, with primitive cathode ray tube (CRT) display systems, was used for studies into the visual perception of patterns associated with the air defence project that lay behind the funding of the computer (Green et al., 1959). The Whirlwind was of course still a huge device, powered by vacuum tubes, and reputed to dim the lights of Cambridge, Massachusetts when operated, but the basic principles of the modern laboratory computing could be discerned. It was a system controlled by the experimenter acquiring data in real time from an experimental subject and displaying results in a dynamic way.

Olsen went on to found Digital Equipment Corporation (DEC) which pioneered the development of the minicomputer. Taking advantage of the developments in integrated circuit technology in the 1960s, minicomputers were much smaller and cheaper (although slower) than the mainframe computer of the time. While a mainframe, designed for maximum performance and storage capacity, occupied a large room and required specialised air conditioning and other support, a minicomputer took up little more space than a filing cabinet and could operate in the normal laboratory environment. Clark & Molnar (1964) describe the LINC (Laboratory INstrument Computer), a typical paper-tape-driven system of that time (magnetic disc drives were still the province of the mainframe). However, it could digitise experimental signals, generate stimuli, and display results on a CRT. The DEC PDP-8 (Programmable Data Processor) minicomputer was the first to go into widespread commercial production, and a variant of it the LINC-8 was designed specifically for laboratory use. The PDP-8 became a mainstay of laboratory computing throughout the 1960s, being replaced by the even more successful PDP-11 series in the 1970s.

Although the minicomputer made the use of a dedicated computer within the experimental laboratory feasible, it was still costly compared to conventional laboratory recording devices such as paper chart recorders. Consequently, applications were restricted to areas where a strong justification for their use could be made. One area where a case could be made was in the clinical field, and systems for the computer-based analysis of electrocardiograms and electroencephalograms began to appear (e.g. Stark et al., 1964). Electrophysiological research was another area where the rapid acquisition and analysis of signals could be seen to be beneficial. H.K. Hartline was one of the earliest to apply the computer to physiological experimentation, using it to record the frequency of nerve firing of Limulus (horseshoe crab) eye, in response to a variety of computer-generated light stimuli (see Schonfeld, 1964, for a review).

By the early 1980s most well-equipped electrophysiological laboratories could boast at least one minicomputer. Applications had arisen, such as the spectral analysis of ionic current fluctuations or the analysis of single ion channel currents, that could only be successfully handled using computer methods. Specialised software for these applications was being developed by a number of groups (e.g. D’Agrosa & Marlinghaus, 1975; Black et al., 1976; Colquhoun & Sigworth, 1995; Dempster, 1985; Re & Di Sarra, 1988). The utility of this kind of software was becoming widely recognised, but it was also becoming obvious that its production was difficult and time consuming. Because of this, software was often exchanged informally between laboratories which had existing links with the software developer or had been attracted by demonstrations at scientific meetings. Nevertheless, the cost of minicomputer technology right up to its obsolescence in the late 1980s prevented it from replacing the bulk of conventional laboratory recording devices.

Real change started to occur with the development of the microprocessor – a complete computer central processing unit on a single integrated circuit chip – by Intel Corp. in 1974. Again, like the minicomputer in its own day, although the first microprocessor-based computers were substantially slower than the contemporary minicomputers, their order-of-magnitude lower cost opened up a host of new opportunities for their use. New companies appeared to exploit the new technology, and computers such as the Apple II and the Commodore PET began to appear in the laboratory (examples of their use can be found in Kerkut, 1985; or Mize, 1985). Not only that; computers had become affordable to individuals for the first time, and they began to appear in the home and small office. The era of the personal computer had begun.

As integrated circuit technology improved it became possible to cram more and more transistors on to each silicon chip. Over the past 25 years this has led to a constant improvement in computing power and reduction in cost. Initially, each new personal computer was based on a different design. Software written for one computer could not be expected to run on another. As the industry matured, standardisation began to be introduced, first with the CP/M operating system and then with the development of the IBM (International Business Machines) Personal Computer in 1981. IBM being the world’s largest computer manufacturer at the time, the IBM PC became a de facto standard, with many other manufacturers copying its design and producing IBM PC-compatible computers or ‘clones’. Equally important was the appearance of the Apple Macintosh in 1984, the first widely available computer with a graphical user interface (GUI), which used the mouse as a pointing device. Until the introduction of the Macintosh, using a computer involved the user in learning its operating system command language, a significant disincentive to many. The Macintosh, on the other hand, could be operated by selecting options from a...