A remote assembler for PDP-8 programs

The general advantages of using large computers to assemble code for laboratory minicomputers are discussed. A PDP-8 assembler implemented under IBM OS/360 is presented, and its use is described.     

A PDP-12 interface for time-code generator/readers

An interrupt-driven time-code reader interface for the Digital Equipment Corporation PDP-12 minicomputer is described.     

A programmable relay and amplifier I/O interface for the PDP-8/E computer

Use of the Digital Equipment Corporation DR8 digital input/output buffer for the PDP-8/E computer is common. However, by itself the DR8 has inadequate output-driving capability for even the smallest laboratory device. A flexible low-cost control network designed to enable a DR8 interface to control any of 12 pico-reed relays for output driving or 8 programmable amplifiers for auditory signal presentation is described.     

Hardware techniques for analog processing using the State Systems PDP-8 I/O interface

Methods are described for construction and use of an analog-to-digital (A/D) converter system which is interfaced with a PDP-8/E through the State Systems interface. Eight bits of one input word are used to bring the results of A/D conversion into the accumulator, and four bits of an output word supply convert and channel-select pulses for the A/D converter and associated eight-channel multiplexer. With a Datei ADC-EH8B1 A/D converter, which digitizes a sample in 4.0 microsec, the system software can perform a conversion in 18.8 microsec. Approximate cost of parts for fabricating the hardware is about $120. Examples of software incorporating the A/D capability are presented for a laboratory computer system used to measure operant response force.     

SPLIT: A sound editor for a PDP-8 computer

SPLIT is a program that helps prepare sounds for use in psychological experiments. Analog signals are converted to digital form and stored on a disk in real time. Digital sound files can be viewed on an oscilloscope display and played back for on-line auditory inspection. Interactive commands allow the user to segment and combine sounds with precise temporal control.     

Economical point plotter interface for a PDP-12 computer

An economical point plotter interface is described for the PDP-12 computer.     

Magnetic tape operating systems for the PDP-8

A magnetic tape operation system (TMS) based on Digital Equipment Corporation’s 4K disk monitor system (DMS), but reconfigured to improve speed and performance on a magnetic tape, is described. The TMS is compared in organization to the DMS configured to run from DECtape. A magnetic tape system device handler for Digital Equipment Corporation’s OS-8, to allow this operating system to be ran from magnetic tape, is included.     

An alphanumeric display program for a PDP-8

Alphanumeric and special characters composed of 5 by 7 dot matrices can be displayed on a cathode ray tube by use of a program written for the PDP-8 family of computers. The CRT surface is specified to contain up to 32 rows with up to 32 characters per row. The 35 dots defining each character require 1.5 msec to generate. Every possible arrangement of spatial and temporal organization among and between strings of characters can be created by simple parameter specification before each trial. The program is designed to operate with a minimal 4k-memory computer configuration, with no special hardware other than an oscilloscope display. The program also permits efficient on-line operation so that an entire experiment can be run quickly and efficiently without further programming. A large number of examples are detailed, and operating procedures are specified.     

A PDP-12 system for on-line acquisition of heart rate data

A research program for investigating the responsiveness of infants at high risk for developing schizophrenia is described briefly. Two measures of reactivity to brief auditory stimuli, the evoked heart-rate response and the evoked potential of the brain, are recorded for analysis by the PDP-12 computer. An interface to the PDP-12, called the R peak detector and R-R interval counter, is used for reducing the EKG to R-R intervals, with an accuracy of ± 1 msec. The current usage of the PDP-12 and its IBM-compatible tape transports is discussed, and proposed developments for on-line statistical analyses of the physiological data and real-time control of the experiment are presented.     

The PDP-8/I as a CAT

A programmed algorithm to compute a weighted ensemble average on a set of output signal realizations is presented. Thus programmed, the PDP-8/I can recover output signals, which are due to periodic input signals, from a noisy system. Arbitrarily, large enhancement of signal-to-noise ratio is attainable. The configuration used is a 4K PDP-8/I with AD08-B analog-to-digital converter.     

PDP-12 stimulus control and data collection for lateralized discrimination learning

A BASIC program that requires a minimum 8K core, 32K disk, KW12-A real-time clock, eight extended operation eight-mode DEC relays with peripheral interface, and user-generated special-function assembly language subroutines for clock and relay control was prepared, using advanced OS/8 BASIC, for conducting laterality studies. It is assumed that the user’s system has a dual tape drive. CRT, and Teletype. Modified IEE readouts have been used for stimulus presentation. Laterality effects and results suggesting application of the procedure in clinical neuropsychological testing have been achieved. This paper describes the rationale for development of the task, summarizes administration procedures, and provides flowcharts of the BASIC program and assembly language special functions, as well as a circuit diagram for the peripheral relay interface.     

A programming system for doing asynchronous I/O on an 8K PDP-12

A programming system is described for the PDP-12 computer system. The system handles input-output requests from user-written routines.     

The PEPL system for control of experiments by a PDP-8 computer

PEPL (Psychology Experiment Programming Language) is a real-time, on-line experimental control system designed for a 4K PDP-8 computer with minimal additional hardware. The system, consisting of the PEPL language, a symbol table for standard DEC assemblers, and an operating system, is capable of asynchronous, timed control of multiple subjects or experiments. The language offers the user high-level instructions for execution control, computation, timing, and I/O control.     

MASTER/SLAVE: Interprocessor communications between PDP-8s

This paper describes an inexpensive, powerful, and easily learned interprocessor communication system for PDP-8 computers. When executed, the master machine exercises control over the slave using commands similar to DEC’s OS/8 copy program, FOTP.     

Quintupling the speed of the PDP-8 DF32 disk system for real-time use

The author has noted some inefficiencies in the operation of the DF32 hardware/software disk system on the PDP-8. While such inefficiencies are not significant when the disk is used only as a store for programs which are called into core from the keyboard, they become important when the disk is used as a real-time backup for core. This paper isolates some of the problems, gives rules for avoiding them, and then describes how the system software was modified to obey these rules. The speed of the modified system is noticeable even when SAVEing and CALLing programs from the keyboard; successive blocks can be transferred between disk and core in one-fifth the previously required time.     

Analysis of variance of one-, two-, and three-treatment designs for a PDP-8

Operating instructions for a series of analysis of variance programs for one-, two-, and three-treatment experimental designs is described. The emphasis is on versatility, speed, accuracy, and sufficiency of output. The on-line aspect of FOCAL allows extensive transformations of raw data. Procedures and terminology conform to Kirk (1968) to provide information for pooling error terms for various models, mean comparisons, and trends analysis. Patches are given for data tape input.     

Time discrimination training of laboratory animals using a PDP-8 computer

The purpose of this paper Is to describe the use of a small, general-purpose digital computer system in the training of laboratory animals to discriminate stimuli on the basis of their duration. The computer hardware and software required for such training, together with some illustrative results from two recent studies, will be described.