Behavior Research Methods & Instrumentation 1978, Vol. 10 (4), 463-467 Special Issue: and Introduction Microcomputers in psychology

JOSEPH B. SIDOWSKI University ofSouth Florida, Tampa, Florida33620

A simple introduction to microcomputers is provided. References are provided for more detailed descriptions of some systems and applications in psychology.

The purpose of this issue of Behavior Research article on " Programmming Languages: Methods & Instrumentation is to provide the behavioral When to Use Which and Why?" (EDN, 270 St. Paul scientist with some selected examples of uses and Street, Denver, Colorado 80206). applications of microprocessors and microcomputers. The introductions to some of the articles in this issue also present elementary information concerning MICROCOMPUTERS this area. Additional information on technology directed to the psychologist may be, found In the past few years, much has been written in both in the April 1978 issue of Behavior Research Metltods & popular and technical publications on microcomputer­ Instrumentation, which reports on the Seventh National based technology. So I shall provide relatively superficial Conference on the Use of On-Line Computers in coverage. The interested reader can refer to the Psychology (listing provided in References section of following articles, which are written simply and clearly this paper). and require no technical background for understanding. I believe that the first attempt by a psychologist to educate psychologists about microcomputers was a talk Frenzel, 1. How to choose a microprocessor. Byte, 1978, presented by Mclean to the 1973 meetings of the 3,124-139. national computer conference noted above. The Gray, S. B. Selecting a micro. Creative Computing, 1977, reprinted version of that presentation is also tutorial 3, 31-33. Isaacson, P. Personal computers for small-business applica­ (Mclean, R. S. Microcomputers for experimental psy­ tions. , 1978,14,53-57. chology. Behavior Research Methods & Instrumentation, North, S. The ABCs of microcomputers: What the be­ 1974, 6, 155-158). A clearly written follow-up was ginning computer hobbyist needs to know. Creative published by: Kehoe, E. J., Frei, L. J., Tait, R. W., & Computing, 1978,4,83-92. Gormezano, I. On microprocessor-based computers. Anonymous. Special focus on home computers: Basic guide to computer buying. Popular Electronics, 1977, Behavior Research Methods & Instrumentation, 1975, 12,57-72. 7, 183-186). Krausman writes of his experiences with a microcomputer kit (Krausman, D. T. The microcom­ A more technical explanation of microcomputers puter kit: An excellent small system development may be found in a special tutorial issue on funda­ tool. Behavior Research Methods & Instrumentation, mentals of microcomputer systems. The reference is 1976, 8, 501-507). His system was used with heart rate Mini-Micro Systems, 1977, Volume 10 (Mini-Micro biofeedback. Systems, 5 Kane Industrial Drive, Hudson, Massachu­ The overwhelming influences of electronics and setts 01749). Readers interested in the specifics of microelectronics are covered in special issues of two microcomputer technology will find a relatively detailed publications: The microelectronics issue of Scientific list of books presented in tabular form in: Osbourne, A. American (September 1977, Volume 237) and the issue What's what in personal computing software. Mini-Micro on the electronics revolution in Science (March 1977, Systems, 1978, 11, 107-11l. The same reference Volume 195, No. 4283). contains tabular listings of available software for various microsystems as well as software vendors. An excellent The Computing Systems: Some Definitions, source of information on microcomputers and micro- Explanations, and Descriptions processors is the "Special Issue on Microcomputers- A microcomputer consists of several components tied From Chips to Systems" of the Cashner publication, together; the microprocessor is only one of these compo- EDN. November 20, 1977. Volume 22. Included is the nents, As with other computers, a memory is required, Fourth Annual Microprocessor Directory, the First inputs and outputs needed, and interconnections wired. Annual Microcomputer Support Chip Directory, the Basically. the microprocessor coordinates activities and Third Annual Microcomputer Systems Directory, and an input/output devices. It performs operations on data 463 464 SIDOWSKI stored in memory and determines the external devices Digital Group. There are, of course, other micropro­ that might provide or have access to the data. Memories cessors, but the systems mentioned above are the most include random-access memory (RAM), which can be popular. Mentioning incorporated systems is merely written into and read from by the computer, and read­ intended to indicate the commonality of subsequent only memory (ROM), which can have information read function and peripheral requirements. from it, but itself cannot store new information. ROM is Sixteen- systems. In this issue, Hansen discusses preprogrammed with a set of instructions. If your 16-bit microcomputers. Sixteen-bit systems include the microcomputer comes with software programmed in National Semiconductor PACE, 8900, the General ROM (e.g., BASIC), the language is operating as soon as Instruments 1600, the Data General MicroNOVA, the system is connected. Unprogrammed ROMs can be the Digital Equipment Corporation LSI·II, the Texas purchased and permanently programmed as required Instruments 9900, and the Fairchild 9440. At present, (programmable read-only memories, PROMs). Erasable prices are higher for the 16-bit systems than for the 8-bit programmable read-only memories () allow systems and supportive software is not as readily the user to reprogram, but both PROMs and EPROMs available, but the advantages of the 16-bit systems will act basically like unprogrammed ROMs once in the be felt shortly. The DEC LSI·II is the most widely used; system. RAM is required to reprogram during computer the Heath Company offers a version called HII. operation. Inexpensive audio-cassette recorders appear Virtually any of these systems can calion the software to be the most popular peripheral memories, but there backing of the PDP-II library. are a number of audio-cassette interfaces and they are The 16-bit MicroNOVA can run all software of the rarely compatible. Using one of the more common line . And the interface standards allows the user more freedom in Intersil 6100, a 12-bit microprocessor, runs on software trading or buying software, but some are used only by written for the DEC PDP-8/e . users of that manufacturer's system. If random-access, Obviously, software cannot be overemphasized. high-speed operation is required, as it is in many research Some of the non-8-bit microprocessors have excellent applications, a floppy. disk unit is needed, and this software bases. For 8- and 16-bit systems, BASIC is greatly increases the cost of what might otherwise be the most common language, but software is being a relatively inexpensive system. developed at a very rapid rate, and FORTRAN and At present, most microprocessors are 8 bit. The most other languages are becoming available. PASCAL for widely used in microcomputers is the 8080, small computers is discussed in this issue by Bowles probably the best documented and upward-compatible and Hollan; COBOL-60 was recently developed by device available. The Zilog l-80, discussed elsewhere of Albuquerque, New Mexico, to run on in this issue of the journal, is newer and more powerful the and 8085 microprocessors and on the and designed to include the 8080 instructions. The l.80; and SKED is available for micros in psychology software written for the 8080 also runs on the l-80. laboratories. But the present availability of software The Z-80 has the advantage of being faster with more for psychological applications is limited. Minicomputers instructions than the 8080 and requires only one 5-V offer a tremendous advantage in this respect. (Argu­ power supply. The 8080 requires three, although the ments could be developed for recommending minis over newer microprocessor uses a single power micros for reasons other than software, but the issue supply and fewer support chips than the 8080. The is not covered in this volume.) Intel 8080 microprocessor is used in microcomputer Addresses ofthe microcomputer companies mentioned systems provided by Digital Group, E & L Instruments, above, as well as others, are listed in Table 1. Heath Company (H8), IMSAl (8080), MITS (Altair . A much discussed element is the bus, a 8080B), PolyMorphic, Processor Technology, and collection of wires or lines that serve as connecting links Vector Graphic. Except for the and Digital that carry signals. Microcomputers have bus systems to Group systems, the S-IOO bus is used. Bus systems will tie components together whether the system is on one or be explained shortly. more than one printed circuit board. The bus itself may The microprocessor has a superior be part of a "" that contains connections instruction set, architecture, and addressing modes, for different circuit cards that can be plugged in. On a but it is slightly slower than the 8080 or Z-80. The MOS single-board system, the bus is arranged to connect the Technology 6502 is somewhat similar to the 6800 and same sort of elements, that is, memories, processor, and is incorporated into the KIM-I microcomputer, which input/outputs. The sets of wires going to different is described elsewhere in this issue. The 6502 micro­ places have the following functions: Power lines supply processor is incorporated into microcomputers marketed the operating voltages (as noted earlier, some micro­ by Ohio Scientific Instruments, Apple Computer, MOS processors, such as the Intel 8080, require three separate Technology (KIM-I), and Commodore PET. Microcom­ power voltages, others require only one); data lines puters built around the Z-80 include the Radio Shack generally carry data in or out of the central processor; system, Technical Design Labs, , and the address lines are most often driven by the central MICROCOMPUTERS IN PSYCHOLOGY 465

Table I Names and Addresses of Some Microcomputer Companies Apple Computer Co., Inc. Fairchild Semiconductor Ohio Scientific 10260 Bandley Drive 464 Ellis St. 11679 Hayden Cupertino, CA 95104 Mountain View, CA 94040 Hiram, OH 44234 Central Data General Instrument Corporation Corporation P.O. Box 2484 Microelectronics Division Microsystem Division Station A 600 West John Street 20630 Nordhoff Street Champaign, IL 61820 Hickville, NY 11802 Chatsworth, CA 91311 Commodore Business Machines, Inc. Heath Company Poly Morphic Systems, Inc. (PET) Benton Harbor, MI 49022 460 Ward Drive 901 California Avenue IMSAI Manufacturing Corporation Santa Barbara, CA 93111 Palo Alto, CA 94305 14860 Wicks Blvd. Processor Technology Corporation Computronics San Leandro, CA 94577 6200 Hollis Street Emeryville, CA 94608 19824 Ventura Blvd. INTEL Corporation Woodland HiUs, CA 91364 3065 Bowers Avenue Radio Shack Compucolor Corporation Santa Clara, CA 95051 2617 West Seventh Street Ft. Worth, TX 76107 P.O. Box 569 Intelligent Systems Corporation Norcross, GA 30091 5965 Peachtree Corners East RCA Corporation Compucorp Norcross, GA 30071 RCA Solid State Somerville, NJ 08876 1901 S. Bundy Drive Intersil Corporation Los Angeles, CA 90025 10900 North Tantau Avenue Southwestern Technical Products Computer Data Systems Cupertino, CA 95014 219 West Rhapsody San Antonio, TX 78216 5460 Fairmont Drive Midwestern Scientific Instruments Wilmington, DE 19808 220 West Cedar Technical Design Labs Cromemco, Inc. Olathe, KS 66061 Research Park 2400 Charleston Road Princeton, NJ 08040 MITS Mountain View, CA 94043 2450 Alamo, Southeast Technico Incorporated Data General Corporation Albuquerque, NM 87106 9130 Red Branch Road Columbia, MD 21045 Microcomputer Division MOS Technology, Inc. Westboro, MA 01581 950 Rittenhouse Road , Inc. Digital Equipment Corporation Norristown, PA 19401 Microcomputer Products Houston, TX 77001 One Iron Way Mostek Marlborough, MA 01752 1215 West Crosby Road Vector Graphic, Inc. The Digital Group Carrollton, TX 75006 717 Lakefield Road West Village, CA 91361 P.O. Box 6528 Motorola Semiconductor Denver, CO 80206 5005 East McDowell Road VideoBrain Computer Company E & L Instruments Phoenix, AZ 85008 150 Wolfe Road 61 First Street National Semiconductor Corporation Sunnyvale, CA 94086 Derby, CT 06418 2900 Semiconductor Drive Zentec Corporation Equinox Division Santa Clara, CA 95051 2400 Walsh Avenue Parasitic Engineering North Star Computers Santa Clara, CA 95050 Box6314 2547 Ninth Street Zilog Albany, CA 94706 Berkeley, CA 94710 10460 Bubb Road Cupertino, CA 95014 processor and received by other parts of the system; bus; in fact, new supportive companies continue to control signal wires have various functions, but as their sprout. title indicates, various component outputs are controlled When the Heath Company announced its H8 micro­ by them. computer, it introduced a bus with 50 lines (the S-50) The S-IOO bus has been called a "standard" because rather than the 100 of the S-IOO Altair. The designers it is used in so many systems, rather than because it of the 50-line bus claimed a number of advantages satisfies the technical definition of the term (Ogdin, C. A. resulting from their past experiences with the S-IOO. Microcomputer buses. Mini-Micro Systems, 1978, 11, These will not be covered here, but detailed information 97-104). It was introduced in about 1975, with the is provided by: Lees,J., & North, S. Heath H8 system. microcomputer. Due to its early introduc­ Creative Computing, 1978, 4, 38-40; and Arnold, R. S. tion and subsequent popularity, rather than enthusiastic A buyer's and builder's guide to the system. acceptance, many companies marketing support Interface Age, 1978, 3, 128-141. equipment designed equipment to work with the S-IOO The KIM-I microcomputer has most of its subsystems 466 SIDOWSKI on one board. A 44-pen edge connector brings the the first computer store chain and now numbers over central processor unit bus out. A motherboard is 30 stores. So the situation for the beginner is much available to expand the bus, so converting the KIM-l bus different than it was for the individual interested in to a S-IOO permits use of the many S-IOO connections. purchasing a minicomputer. A micro not only may be The ability to convert from one bus to another purchased at the corner store, but the salesperson may obviously offers many advantages for any system. also supply local maintenance and advice on setting up The GPIB is a general-purpose interface bus that has the system for specific applications. Local clubs are been adopted as a standard by IEEE. The maximum numerous, and extensive information is exchanged in the effective bus length for this system is said to be about more popular publications, such as Creative Computing 16 ft, which provides some advantage in connecting to (P.O. Box 789-M, Morristown, New Jersey 07960), Byte peripherals. The three buses mentioned earlier have their (70 Main Street, Petersborough, New Hampshire 03858), operational speeds restricted to an overall length of Interface Age (P.O. Box 1234, Cerritos, California about 2 ft, which generally means that interface boards 90701), and Dr. Dobb'sJournal ofComputerCalisthenics must be plugged into the bus at the cabinet. The GPIB and Orthodonta (EI Camino Real, Box E, Menlo Park, connector is on the back of the Commodore PET California 94025). Of course, a great deal of the infor­ microcomputer, one of the most inexpensive and best mation concerning applications will not be of interest selling complete systems on the market today. to the research-oriented psychologist, but these publica­ Additional information on bus systems may be found tions carry much information of value on software, in articles or advertisements covering individual micro­ hardware, technological developments, evaluations of computer systems. Also refer to the following: systems, and so on. More of the efforts of the National Conference on the Use of On-Line Computers in Duncan, M. Some guidelines for users of the RS-232 or Psychology are being directed to microcomputers, so the DART.Interface Age. 1977,2,46. that organization can be expected to act as a prime Notari, R. A 16-bit system for the S-100 bus that holds source of information for the behavioral scientist. its own against a mini. Interface Age, 1977, 2, 72-74. Purser, R. E. S-100 compatible computer kits. Creative Computing, 1977,3,4144. CONTENTS OF THIS JOURNAL ISSUE Purser, R. S-100 bus compatible systems-OEM supple­ ment and price list. Interface Age, 1977, 2, 76-87. An attempt has been made to provide the reader with a sample of the work now being done with micro­ Chamberlin provides an easy-to-read article on bus computers in psychology. The first three sections deal systems in a recent issue of Popular Electronics with three different systems, the PET, the KIM-I, and (Chamberlin, H. Computer bit: Bus systems. Popular the LSI-II. Another use of the PET may be found in Electronics, January 1978, p. 77-79). the section on observational research; Durrett (1978) Fortunately, a number of converters have been discusses the PET and the Radio Shack (Tandy Corpora­ designed and continue to be introduced by commercial tion) TRS-80 systems in a recent issue of this journal. firms that allow microcomputers with one type of bus to Murray and Lawler (1978) describe a KIM-l interface use other interface boards. In this issue, R. N. Johnson for aversive conditioning applications in the same notes one such supplier for the PET system. An issue. increasing number of others are available, including It is obvious that only a small sample of the available Pickles and Trout of Goleta, California (S-IOO to microcomputer systems are mentioned in this volume. IEEE-488 interface for $325). At present the PET is probably the best selling complete Ogdin states that only three buses are contenders in system on the market; it was introduced as a stand-alone the contemporary popularity race: These are the LSI-II system in 1977, at the National Computer Conference (DEC), the MULTIBUS (INTEL) originally used in the in Dallas, Texas, and caused a stir throughout the microcomputer development system, and the computer industry because of the price ($595 and S-IOO. The Heath H8 bus scheme, she states, is "doomed $795) and package (keyboard, display, cassette system, to a long, slow and painful death as technology marches processor, memory, interface, and software). The Heath on." The same fate is predicted for the S-loo because systems were announced but not shown at the same both are dedicated to the Intel 8080 microprocessor meetings. I suspect that a reasonable number of Heath control signals. systems will be adopted by research psychologists Becoming involved. Becoming acquainted with micro­ because ofindividual satisfaction with Heathkit products computers is a relatively simple matter: You merely go in general in the past. But the H8 system built around to the local Radio Shack store or to a computer store the Intel 8080 is priced at $1,239.75 with 4K memory, and examine one. Computer stores that specialize in serial I/O and cassette interface, a video terminal, and micros are located in virtually every large or medium-size cassette recorder-player. The Heath System IV costs city in the country. The world's first computer store was $3,350 with the Hll (LSI-ll-based) computer, 4K opened in Los Angeles, California, in 1975. Byte, Inc. is memory, parallel interface and serial interface, paper- MICROCOMPUTERS IN PSYCHOLOGY 467 tape reader-punch, and DECwriter. The TRS-80 from advertised (battery-operated Model 600 microcomputer, Radio Shack is comparable in price with the PET with Adaptive Systems, Inc., P.O. Box 1481, Pompano Beach, somewhat similar built-in features. It will be sold Florida 33061). eventually at 2,100 stores, which should make the Finally, three groups of authors address the uses of system a relatively popular laboratory adjunct. Addi­ microsystems for psychological testing and assessment, tional information on the PET and TRS-80 may be reflecting the potential for the immediate use of this found in the following sources: technology in clinical settings.

Brown, 1. Commodore PET. Creative Computing, 1978, REFERENCES 4,24-26. Fylstra, D. User's report: The PET 2001. Byte, 1978, 3, BROWN, E. 1., & DEFFENBACHER, K. Microcomputers big 114-127. and little: Selecting a low-cost laboratory computer network. Gray, S. B. Radio Shack TRS-80. Creative Computing, Behavior Research Methods & Instrumentation, 1978, 10, 1978,4, 35-37. 241-245. CROSSMAN, E. K., & WILLIAMS, 1. G. A multi-user on-line The DEC LSI-II and other I6-bit microcomputers 8080 microcomputer system. Behavior Research Methods & obviously have advantages, and these are covered in Instrumentation, 1978, 10, 254-258. DURRETT, H. J., JR. Inexpensive microcomputer systems for this issue by Hansen. Palya in this volume provides research and instruction: A dream or reality? Behavior an invaluable source for LSI-II-compatible products. Research Methods & Instrumentation, 1978, 10, 345-351. Timesharing, interfacing, and networks are of concern GOLDBAND, S. Input and output for microprocessors. to microcomputers as they were and continue to be to Behavior Research Methods & Instrumentation, 1978, 10, 244-253. minicomputerists. Four articles cover some aspects of McKNIGHT, 1. R., WATERS, B. K., & LAMOS, J. P. Develop­ these in this volume. ment and evaluation of a microcomputer testing terminal The five experimental articles cited are merely for testing and instruction. Behavior Research Methods & samples of the many ways in which the technology is Instrumentation, 1978, 10,340-344. being used in the laboratory; Hale and his coverage of MURRAY, D. M., & LAWLER, J. E. A KIM-l microprocessor interface for aversive conditioning applications using mul­ British psychology departments provides a number tiple subjects. Behavior Research Methods & of others as he reports on the state of the art in the Instrumentation, 1978, 10, 334-339. behavioral sciences in Great Britain. PAVEL, M. What is a microprocessor? Behavior Research The gathering of data in naturalistic settings is being Methods & Instnmentation, 1978, 10, 238-240. revolutionized by electronic developments. The three POLSON, P. G. Microprocessors: Their impact on real-time computing in psychology. Behavior Research Methods & articles covering observational and field research tech­ Instrumentation. 1978, 10, 139-147. nology provide illustrations. Microprocessor-based SANTA, 1. 1., & STREIT, P. A microprocessor reaction time systems are allowing for limited but immediate analysis laboratory. Behavior Research Methods & Instrumentation, of the data. Development of battery-operated micro­ 1978, 10, 352-355. SIDOWSKI, J. B. Observational research: Some instrumented computers may offer enhanced data-handling capabilities systems for scoring and storing behavioral data. Behavior in the field. A battery-operated system has recently been Research Methods & Instrumentation, 1977, 9,403-404.