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RAMP: A PDP-8 MULTIPROGRAMMING SYSTEM FOR REAL-TIME DEVICE CONTROL

IP.com Disclosure Number: IPCOM000128418D
Original Publication Date: 1967-May-01
Included in the Prior Art Database: 2005-Sep-15
Document File: 12 page(s) / 47K

Publishing Venue

Software Patent Institute

Related People

Mills, David: AUTHOR [+3]

Abstract

The following sections describe the organization of a PDP-8 multiprogramming system that provides real-time device control and task-switching operations. The system, called RAMP [ Footnote ] Random Access Multiple Program, from the system by the same name for which this program was originally written. for convenience here, operates under interrupt control. using integral task queue and buffer management routines. A simple command language is implemented, which provides control over both debugging and normal operational procedures and operates entirely within the system. The system has been adapted to a number of device-control applications including those of large-scale audio and data circuit switching, and computer-driven cathode ray display supervision.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 8% of the total text.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

RAMP: A PDP-8 MULTIPROGRAMMING SYSTEM FOR REAL-TIME DEVICE CONTROL

David Mills

CONCOMP: Research in Conversational Use of Computers
F. H. Westervelt, Director, ORA Project 07449 supported by: DEPARTMENT OF DEFENSE, ADVANCED RESEARCH PROJECTS AGENCY, WASHINGTON, D. C.

CONTRACT NO. DA-49-083 OSA-3050, ARPA ORDER NO. 716 administered through: OFFICE OF RESEARCH ADMINISTRATION, ANN ARBOR, May 1967

TABLE OF CONTENTS

INTRODUCTION.....1
GENERAL ORGANIZATION.....1
PART I:THE BASIC SYSTEM NUCLEUS.....2

     INTERRUPT IDENTIFIER.....2
INTERRUPT ROUTINES.....3
BUFFER MANAGEMENT ROUTINES.....3
TASK-SWITCHING PROCESSOR.....4
UTILITY ROUTINES.....9
COMMAND-LANGUAGE INTERPRETER.....11
APPLICATIONS.....13
PART II:BASIC SYSTEM EXTENSIONS FOR DEVICE CONTROL.....14

     DEVICE INTERFACE.....15
FILE STRUCTURES.....16
COMMAND EXTENSIONS.....18
PART III:MECHANICS OF RAMP.....19
APPENDIX: COPY MODULE COMMANDS FOR RAMP.....23

INTRODUCTION

The following sections describe the organization of a PDP-8 multiprogramming system that provides real-time device control and task-switching operations. The system, called RAMP 1for convenience here, operates under interrupt control. using integral task queue and buffer management routines. A simple command language is implemented, which provides control over both debugging and normal operational procedures and operates entirely within the system. The system has been adapted to a number of device-control applications including those of large-scale audio and data circuit switching, and computer-driven cathode ray display supervision.

1 Random Access Multiple Program, from the system by the same name for which this program was originally written.

University of Michigan Page 1 May 01, 1967

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RAMP: A PDP-8 MULTIPROGRAMMING SYSTEM FOR REAL-TIME DEVICE CONTROL

The techniques used are believed to represent a good compromise between the large memory requirements of a full- scale general multiprogramming system and a more specialized system tailored for faster but more restricted operation. Some of these techniques may seem a little strange to conventional multiprogramming practice and for this reason are described in greater detail below.

GENERAL ORGANIZATION

The principal components of the basic RAMP system include:

1. An interrupt identifier that identifies the device causing an interrupt and calls the appropriate subroutine;
2. a set of interrupt routines that services the device causing an interrupt and transmits data between the device and an attached buffer;
3. a set of buffer management routines that services the buffers attached to the keyboard, printer, and other special devices;
4. a task-switching processor that maintains a queue of active tasks and executes each as required;
5. a set of utility routines for keyboard and printer character formatting and conversion; and
6. a command language interpreter that decodes system commands entered via the tele...