NOVA SKED: A behavioral notation language for Data General minicomputers

A state notation language (NOVA SKED) for the experimental control and collection of data from operant behavior experiments by Data General NOVA series minicomputers is described. NOVA SKED is based on the SKED system written for the Digital Equipment Corporation PDP8 series of minicomputers. The NOVA SKED state notation syntax enables diagramming experimental procedures directly and precisely by the operant experimenter, who need not be familiar with computers. This syntax can then be compiled by the computer into programs that operate under the SKED run-time system (RTS). The SKED RTS operates in a timesharing mode that allows up to 16 experimental stations to function simultaneously and independently from each other. NOVA SKED is a “stand-alone” system that collects and stores data on digital magnetic tape.     

NOVA SKED II: A behavioral notation language utilizing the Data General Corporation real-time disk operating system

A software system (NOVA SKED) was developed for the experimental control and collection of data from operant behavior experiments that is compatible with the Data General Corporation real-time disk operating system (RDOS). NOVA SKED is based on the SKED state notation language originally implemented on Digital Equipment Corporation PDP-8 series of minicomputers. The system includes a compiler written in FORTRAN, a multitasking run-time system that can be configured to run up to 30 stations, a data back-up system, standard data manipulation programs and subroutines, and user manuals.     

Time-sharing SKED and OS/8: A new version

A new time-sharing SKED program has been developed to simultaneously conduct up to 12 behavioral experiments while the OS/8 operating system is used in the “background.” The new system provides improved control over the SKED program while allowing the experimenter to develop new programs or analyze data during the experimental session. A minimum of 16K of memory and an OS/8 device is required to use this system.     

MicroSKED

MicroSKED has transferred the assets of SKED to a microprocessor. Designed around the 6502 microprocessor, MicroSKED contains an editor, compiler, and run-time system. The basic system has 512 words of user memory, 124 inputs, 4 outputs, a time-of-day clock, a keyboard, and a display. The projected cost of the system is $300. The system may be expanded. Differences between SKED and MicroSKED are examined.     

An introduction to state notation and SKED

SKED is a minicomputer operating system based on the functional use of state notation as a programming language. An overall view of the operating system, state notation, and the hardware necessary to simultaneously control as many as 12 experimental stations is provided.     

Analog SKED

Analog data can now be handled by SKED. Through the use of F3s, input, output, decisions, and analyses can be performed on analog data. A new command has been added to SKED. The trade off between number of boxes and resolution is discussed.     

Time-Share SKED acquisition of analog data: Blood pressure and heart rate

A computer program records, within the framework of the SKED minicomputer operating system, blood pressure and heart rate data in behavioral experiments. By repetitive (500-Hz) analog-to-digital conversions of a blood pressure waveform, the program finds and stores successive-beat systolic and diastolic pressures, and intersystolic intervals. SKED initiates and terminates blood pressure recording periods, and controls all experimental procedures. The program is currently operational, servicing four independent stations simultaneously, with sufficient computer operating time remaining to service low-priority background programs.     

PASTOR: A new schedule programming language

A new schedule programming language is presented, including its implementation on a PDP-11 running under RSX-11M. This language combines modern syntax concepts of PASCAL with the state notation of SKED. The present implementation includes event-driven activation for fast response time and shared code for minimal storage requirements, allowing the simultaneous control of many experiments.     

A new OS/8 SKED

A new SKED run-time system and compiler have been designed for use under the OS8 operating system. OS8 is a set of programs designed by DEC for the PDP8 computer with 8K or more core memory locations and a mass-storage device (disk, or DEC-tape). The advantages of OS8 include operator convenience, device independent input-output, standard file formats, and convenient program chaining as well as a set of standard data analysis programs. The new compiler, OSCOMP, differs from the previous version in two ways. The first new feature is the ability to process named input and output files on any OS8 compatible peripheral. The second feature is the utilization of 8K of core, permitting compilation of longer state tables than could be processed with the earlier version. Furthermore, with a disk as the OS8 peripheral, the compilation process is essentially instantaneous, for state tables previously requiring from 3–30 min with paper tape devices. The new run-time system, OSRTS8, contains a variety of new features. The most important improvements are the abilities to record data on the OS8 peripheral as well as to read state tables stored as files on the mass-storage device. Other new features include chaining of state tables, automatic start, automatic output file specification, and capability for as many as 12 simultaneous stations.     

Revision of SKED: Needs and desires

Modifications are suggested for Snapper’s SKED system.     

Use of a notation system for digital control and recording

This paper describes (1) a notation system for digital control and recording, (2) some improvements to SKED, and (3) future developments and uses of minicomputers.     

Time-of-day clocks and SKED: Techniques and applications

Modifications of SKED have been developed which incorporate a time-of-day clock into the basic SKED run-time systems. These clocks provide the experimenter with a means of recording the exact time of day at which events occur, as well as starting and stopping experiments and dumping data at specific times of the day. One type of clock is a hardware device that can be read to provide the number of minutes elapsed since midnight. A simple algorithm can be used to convert this value to hours and minutes. A second type of system maintains the current time by accumulating system clock ticks.     

Interfacing for the SKED system

Four new interface modules, a new input module, a duration measuring module, an omnibus module, and a high-speed reader module, have been developed for the SKED interface to further optimize the use of the small computer in the laboratory.     

PROCODER: A professional tape control,coding, and analysis system for behavioral research using videotape

PROCODER is a software system for observing and coding events that have been recorded on videotape. The system uses a personal-computer-based tape controller to control a VHS tape while observations are recorded. Frequencies of events, durations of events, and calculations of inter-observer agreement of events or intervals are included. Data can be output in ASCII format for use with other statistical programs. A sample study in which the system is used is described as well.     

Programming special functions in the SKED system

Machine language subroutines can be integrated with the SEED system. These subroutines can shorten lengthy programs that could otherwise be handled by SKED, and can provide complex decision functions, data recording schemes, and software for new peripheral devices. Rules and examples for each function will he presented.     

Alternative versions of SKED: Current systems and future plans

SKED was originally designed to be the least expensive user-oriented system for on-line control and recording of behavioral experiments. Recent price reductions in the cost of memory and peripheral devices has permitted cost-effective development of more convenient and powerful versions of the software.     

A simple BASIC language laboratory control system for microcomputers patterned after SKED®

Microcomputers such as the TRS-80, when equipped with a simple digital input-output interface, become capable of completely controlling laboratory experiments. BASIC language software has been developed that allows simplified programming of experiments using the “state” concepts of the SKED system.     

FOCAL,FORTRAN, and BASIC programs for reformatting and analyzing data collected by the SKED program

Several programs have been written in the FOCAL, FORTRAN, and BASIC languages for reformatting and analyzing SKED data. These programs include selection and explicit labeling of sets of recording counters representing distributions and/or total counts of events, several general manipulations of distributional data, and standard statistical treatment of distributions.     

SKED-controlled experimentation in an undergraduate instructional laboratory

A SKED-based facility for undergraduate instructional research has been operating for over a year. The two-computer approach, with one machine for programming and the other for running experiments, is used. Criteria for computerized undergraduate research laboratories, benefits of SKED, and the two-computer approach are discussed.