FORTRAN control of graphics on the amiga microcomputer

The graphic capabilities of the Amiga microcomputer offer considerable potential for perceptual and cognitive research. These capabilities, however, are most easily accessed via the C programming language. Manipulating Amiga graphics hardware is considerably more difficult for the FORTRAN programmer. A package of FORTRAN 77 routines is described which has been designed to allow images to be easily processed and presented by means of calls from a FORTRAN experiment control program.     

FORTRAN control of graphics on the amiga microcomputer

The graphic capabilities of the Amiga microcomputer offer considerable potential for perceptual and cognitive research. These capabilities, however, are most easily accessed via the C programming language. Manipulating Amiga graphics hardware is considerably more difficult for the FORTRAN programmer. A package of FORTRAN 77 routines is described which has been designed to allow images to be easily processed and presented by means of calls from a FORTRAN experiment control program.     

Amiga 1000 hardware timing and reaction-time key interfacing

A method of hardware reaction timing with millisecond accuracy, using one of the Amiga’s CIA 8520 chips, is described. The registers of this chip can be set to enable cascaded timing that functions independently of the CPU and, thereby, avoids the problems of software timing in a multitasking environment. In addition, the interfacing of a pair of reaction-time keys to one of the Amiga’s game controller connectors and a program for polling this port for keypresses are described.     

Frequency synthesis with the Commodore Amiga for research on perception and memory of pitch

The potential of the Commodore Amiga as a digital synthesizer for research and demonstration in psychoacoustics and memory is discussed. Economy, ease of use, flexibility, portability, and accuracy outweigh disadvantages of narrow bandwidth, narrow dynamic range, and storage limitations for many applications encountered in pilot research and education. The Amiga also bears serious consideration for psychoacoustic studies requiring frequencies below 4000 Hz and modest signal-to-noise ratio, as exemplified by an implementation for research in absolute judgment, similarity scaling, and sequential pattern tracking.     

Software-based visual psychophysics using the Commodore Amiga with Deluxe Paint III

Often it is useful to produce visual displays that allow for pilot testing of experimental hypotheses, which let the experimenter examine effects reported by others, or which can be used for at least some serious experimentation (e.g., decrement in visual illusions with practice). The combination of the Amiga computer and Deluxe Paint III software is ideal for this purpose. The ease with which graphic displays can be produced, coupled with the new animation facility in the software, enables method-of-adjustment psychophysical experiments to be produced in a very short time. Worked examples are given, and the relative merits and shortcomings of the Amiga computer for these purposes are discussed.     

Visual stimuli on the Commodore Amiga: A tutorial

The Commodore Amiga home microcomputer, together withDeLuxePaint, a commercial software package, can generate many useful visual stimuli, including random-dot stereograms, apparent motion, texture edges, aftereffects from dimming and brightening, motion aftereffects, dynamic random noise, and drifting and counterphase gratings. Videotapes can readily be made of these displays. No programming experience is necessary.     

An experiment control system for the Amiga microcomputer

The Commodore Amiga microcomputer, with its powerful and versatile hardware features, is well-suited to many areas of behavioral research. The complexity of the hardware and software, however, creates considerable difficulties for the researcher who wishes to construct real-time experiment-control programs. The present article describes a coordinated package of routines that have been designed to support experiment-control programs written in FORTRAN 77. The package was constructed specifically for cognitive research on verbal processes, but is sufficiently flexible to be useful in a variety of other applications. The functions performed by the program include the construction of stimulus displays, response detection, and timing operations.     

Coding simultaneous experiments as independent FORTRAN subroutines

Simultaneous experiments can be coded as separate FORTRAN subroutines which pass requests for critical times and events to a coordinating subroutine named CHECK. These requests are stored in a “request table.” When all the experiments are temporally dormant, CHECK loops through the request table, checking each request. Whenever CHECK discovers that one of the requested times or events has occurred, it CALLs the subroutine of the appropriate experiment. In addition to supporting simultaneous experiments, this system permits a simpler style of programming experiments than that possible in unenhanced FORTRAN. This simplicity is largely due to the fact that the “loop and check” control structures are implemented in the CHECK subroutine and hence are transparent to the programmer.     

Three subroutines for dealing efficiently with permutations

Subroutines for generating and indexing permutations are described. The first generates a permutation of N integers, depending on the value of an index that may take on values between 1 and N!, the number of possible permutations of length N. The second subroutine calculates an index from a given permutation that denotes its position in the list of all possible permutations of that length. The last subroutine generates random permutations of any given length.     

SCV-A general subroutine for the selection of combinations of variables

SCV is a FORTRAN IV subroutine for sequencing combinations of variables. Selection of the combinations can be random with or without replacement and with equal or unequal frequencies of occurrence. Application is illustrated in terms of an interactive process-control experiment, but the subroutine is applicable to any problem requiring the generation of multidimensional sequences or the permutation of a set of numbers.     

SCORIT: A computer subroutine for scoring electrodermal responses

Given digitized electrodermal response records sampled at a rate of 20/sec and at a sensitivity level between 140 and 170 ohms, a computer subroutine for scoring skin resistance responses is described. It is designed to score multiple responses on a trial, which makes it particularly suitable for classical conditioning experiments involving long interstimulus intervals. The subroutine returns to the main program response latency, base resistance, peak resistance, and time from base to peak. Since SCORIT is written in FORTRAN IV, it can be employed in virtually any modern central computing facility at costs substantially below those involved in hand scoring.     

More on millisecond timing and tachistoscope applications for the IBM PC

This paper describes a method of establishing time intervals at a precision of better than 1 msec, using QuickBASIC 4.0, for running real time experiments on an IBM PC without an 8087 coprocessor. This method is far superior to the TIMER function provided by BASIC, which has a precision of only 110 msec. Also described is an assembly language subroutine that corrects a problem in QuickBASIC 3.0 and QuickBASIC 4.0 to allow proper switching between screens in the CGA text mode for use of the PC as a tachistoscope. A tachistoscope program listing shows how to use the screen subroutine and how to establish intertriai intervals and record reaction times using the timing subroutines.     

Millisecond interval timer and auditory reaction time programs for the IBM PC

Many types of behavioral research require the determination of elapsed time, for example to establish interstimulus intervals and to measure reaction time. The use of an IBM PC for on-line control of such applications is limited by the poor timing resolution ordinarily available. The IBM BIOS time information that is used for the BASIC TIMER function can result in interval timing errors as great as 110 msec. A machine language subroutine is described that can provide 1-msec accuracy. A BASIC program is also described that employs this subroutine to measure auditory reaction time.     

Graphics software and hardware for RT-11 systems

A general-purpose graphics package is described that allows the user to generate figures with a supraset of the basic CalComp plotting subroutines. The software runs under RT-11 on an LSI-11 with 28K words of memory. The graphics subroutine library is approximately 200 blocks long. The plotting tasks are passed over an RS 232 line to a simple extension of an inexpensive and commercially available graphics controller. The controller implements these tasks as plotting instructions to a color television, a vector display, and a digital plotter. The graphics subroutines are written in FORTRAN and are invoked by the user as subroutine calls from a FORTRAN program. The graphics controller is a modified Motorola “Micro Chroma 68 Kit.” The board is based on the 6808 microprocessor and 6847 video controller. It provides eight graphic modes from 64 by 32 eight-color graphics to 128 by 192 four-color graphics to 256 by 192 two-color graphics. The present software and hardware implements the graphics subroutines as 256 by 192 two-color graphics, as 512 by 512 vector graphics, and as stepping instructions for a digital plotter.     

PET Flasher: A machine language subroutine for timing visual displays and response latencies

PET Flasher presents a one-line stimulus display at any location on a PET/CBM (Commodore Business Machines) screen and measures reaction time from display onset. Display duration is accurately controlled in 16.7-msec steps, and reaction time measurement is accurate within ±1 msec. PET Flasher is easily incorporated within any PET/CBM BASIC program, since as a subroutine, it is called only when precise timing operations are required.     

Measurement of directional lever response reaction time with the Commodore 64

Routines are described for timing directional lever responses with the Commodore 64 micro-computer. Millisecond reaction timing is carried out with on-board hardware clocks, and lever responses are detected by monitoring the position of a joystick interfaced to a controller port. In a demonstration program, a machine code subroutine is used to measure the reaction times of lever responses in a spatial relations task. In addition, modifications to the demonstration program are suggested to adapt it for use with other tasks.     

FACAIC: Model selection algorithm for the orthogonal factor model using AIC and CAIC

This paper describes the authors' FORTRAN algorithm FACAIC for choosing the number of factors for an orthogonal factor model using Akaike's Information Criterion. FACAIC utilizes the IMSL subroutine OFCOMM.The authors dedicate this algorithm to Professor Hirotugu Akaike in appreciation of his pioneering work on AIC which was originally intended for the factor analysis and other statistical model identification problems.     

Measuring reaction time with millisecond accuracy using the TRS-80 microcomputer

A machine language subroutine is proposed for measuring reaction time with millisecond accuracy using the TRS-80 microcomputer. This timer is accurate to 1 msec in the first 30,000 msec and to 5 msec in the first 65,000 msec (1 part in 10,000).     

Exact conditional tests for cross-classifications: Approximation of attained significance levels

A procedure is proposed for approximating attained significance levels of exact conditional tests. The procedure utilizes a sampling from the null distribution of tables having the same marginal frequencies as the observed table. Application of the approximation through a computer subroutine yields precise approximations for practically any table dimensions and sample size.     

Calculation of the tetrachoric correlation coefficient

A new subroutine has been developed for calculating the terachoric correlation coefficient. Recent advances in computing inverse normal and bivariate normal distributions have been utilized. The iterative procedure is started with an approximation with an error less than±.0135.I am grateful to the Editor for valuable suggestions for improving the presentation.