The Project Gutenberg EBook of Preliminary Specifications: Programmed Data
Processor Model Three (PDP-3), by Digital Equipment Corporation

This eBook is for the use of anyone anywhere at no cost and with
almost no restrictions whatsoever. You may copy it, give it away or
re-use it under the terms of the Project Gutenberg License included
with this eBook or online at www.gutenberg.net

Title: Preliminary Specifications: Programmed Data Processor Model Three (PDP-3)
October, 1960

Author: Digital Equipment Corporation

Release Date: July 20, 2009 [EBook #29461]

Language: English

Character set encoding: ASCII

*** START OF THIS PROJECT GUTENBERG EBOOK PDP MODEL THREE (PDP-3) ***

Produced by Gerard Arthus, Katherine Ward, and the Online
Distributed Proofreading Team at http://www.pgdp.net

PRELIMINARY SPECIFICATIONS

---

PROGRAMMED DATA PROCESSOR
MODEL THREE
(PDP-3)

---

October, 1960

Digital Equipment Corporation
Maynard, Massachusetts

TABLE OF CONTENTS

INTRODUCTION 1

General Description 1
System Block Diagram 1
Electrical Description 4
Mechanical Description 4
Environmental Requirements 5

CENTRAL PROCESSOR 6

Operating Speeds 6
Instruction Format 6
Number System 7
Indexing 8
Indirect Addressing 8
Instruction List 9
Manual Controls 20

STORAGE 22

STANDARD INPUT-OUTPUT 23

Paper Tape Reader 23
Paper Tape Punch 24
Typewriter 24

OPTIONAL INPUT-OUTPUT 26

Sequence Break System 26
High Speed In-Out Channel 26
Magnetic Tape 27
CRT Display 33
Real Time Clock 33
Line Printer 34

UTILITY PROGRAMS 35

FRAP System 35
DECAL System 35
Floating Point Subroutines 36
Maintenance Routines 37
Miscellaneous Routines 37

INTRODUCTION

GENERAL DESCRIPTION

The DEC Programmed Data