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.     

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.     

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.     

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.     

Revision of SKED: Needs and desires

Modifications are suggested for Snapper’s SKED system.     

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.     

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.     

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.     

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.     

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.     

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.     

The BUS-ALL: An inexpensive set of interface for the SKED system

A cost-effective relay-transistor interface has been developed for connecting the minicomputer with the experimental environment. The interface contains a 10-msec clock, input (response) channels, and output (stimulus channels.     

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.     

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.     

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.     

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.