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-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.     

SKED systems: Paper tape,Tennecomp, and OS/8

The SKED system has been developed at different levels of complexity and power for differing hardware configurations. The simplest of these, and the least expensive, is the paper-tape SKED system. Some of the drawbacks associated with the use of paper tape are absent in the Tennecomp magnetic tape cartridge system. Users with mass storage capabilities can make use of the OS/8 operating system (copyright DEC) to speed up all aspects of the SKED system (especially editing, compilation, and loading of programs), and take advantage of a file-oriented system structure for data storage and analysis.     

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.     

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.     

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.     

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 optically isolated digital interface for the SKED system

A digital interface to support the SKED software system in recent versions of the PDP-8 computer. One printed circuit card of interface logic and optical isolators can be installed in the OMNIBUS to provide 24 input and 36 output lines to external panels containing input simulation switches and input or output indicators.     

Revision of SKED: Needs and desires

Modifications are suggested for Snapper’s 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.     

Data-collection strategies in SKED

One advantage of the use of computers in the behavioral sciences is in the area of data collection. Regardless of the specialty area, the more sophisticated the issue being addressed, typically the greater the need for a more detailed analysis of data. This paper traces data-recording strategies in SKED from the simple counting of events to advanced-time and correlational analyses. Examples of common measures, such as interresponse times, and advanced measures, like sequential dependencies, will be discussed.     

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.     

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.     

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.     

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.     

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.     

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.     

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.