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ENGINEERING DESIGN REPORT: PDP-8/CR01B CARD READER INTERFACE

IP.com Disclosure Number: IPCOM000128415D
Original Publication Date: 1967-Aug-01
Included in the Prior Art Database: 2005-Sep-15
Document File: 4 page(s) / 24K

Publishing Venue

Software Patent Institute

Related People

Lundstrom, Stephen F.: AUTHOR [+3]

Abstract

The CR01B card reader is a standard interface option available on the Digital Equipment Corporation PDP-7 computer. This report describes the necessary additions to the standard PDP-7/CR01B card reader interface to allow it be used as a PDP-8/CR01B card reader interface in addition. The description of the additions is preceded by a discussion of the CR01B characteristics of concern to a programmer. Before beginning the main discussion, a word about the origin of this project is in order. The PDP-7 in the Logic of Computers Group was originally purchased with a CR01B card reader. After a short while, it was observed that the card reader could be used to the best advantage if it was available as an input device on the PDP-8(338). The reasons for this were threefold. First, the PDP-7 has, as standard equipment, high speed paper tape handling equipment while the PDP-8(338) does not. Nor does the PDP-8 (338) configuration currently have high speed paper tape handling equipment. Second, the necessary programming support for generation of PDP-8 binary card decks was complete, while plans for corresponding PDP-7 facilities were not yet defined. Third, the plans to interface the PDP-7 to an IBM 1800, which had a card reader, were well under way. It was for these reasons that it seemed practical to consider the interface additions described below.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

ENGINEERING DESIGN REPORT: PDP-8/CR01B CARD READER INTERFACE

Stephen F. Lundstrom

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

August 1967

ENGINEERING DESIGN REPORT: PDP-8/CR01B CARD READER INTERFACE

Stephen F. Lundstrom

INTRODUCTION

The CR01B card reader is a standard interface option available on the Digital Equipment Corporation PDP-7 computer. This report describes the necessary additions to the standard PDP-7/CR01B card reader interface to allow it be used as a PDP-8/CR01B card reader interface in addition. The description of the additions is preceded by a discussion of the CR01B characteristics of concern to a programmer.

Before beginning the main discussion, a word about the origin of this project is in order. The PDP-7 in the Logic of Computers Group was originally purchased with a CR01B card reader. After a short while, it was observed that the card reader could be used to the best advantage if it was available as an input device on the PDP-8(338). The reasons for this were threefold. First, the PDP-7 has, as standard equipment, high speed paper tape handling equipment while the PDP-8(338) does not. Nor does the PDP-8 (338) configuration currently have high speed paper tape handling equipment. Second, the necessary programming support for generation of PDP-8 binary card decks was complete, while plans for corresponding PDP-7 facilities were not yet defined. Third, the plans to interface the PDP-7 to an IBM 1800, which had a card reader, were

University of Michigan Page 1 Aug 01, 1967

Page 2 of 4

ENGINEERING DESIGN REPORT: PDP-8/CR01B CARD READER INTERFACE

well under way. It was for these reasons that it seemed practical to consider the interface additions described below.

PROGRAMMING CHARACTERISTICS

The CR01B card reader, with the interface additions, operates under the programmed I/O control on the PDP-8. The instructions available to the PDP-8 programmer and their uses are described below.

Mnemonic Symbol Operation Executed

CRRS (6701)

Skip on card reader ready flag. When a card is present in the reader read station and power is in at the card reader, the next instruction is skipped. The flag is turned off during the card feed cycle before column one is read and turned back in after column 80.

CRRB (6702 or 6742)

Read data. This instruction ORs data from the card reader into the AC in a format specified by the previous select instruction (see below), and clears the data ready flag.

CRSF (6741)

Skip on card reader data flag. When the card reader data flag is set, indicating that a card column is present and ready to be read, the next instruction is skipped. This flag is connected to the program interrupt fac...