- ATlaT UN/~ SYSTEM V RELEASE 4 Migration Guide UNIX Software Operation Copyright 1990,1989,1988,1987,1986,1985,1984,1983 AT&T All Rights Reserved Printed In USA Published by Prentice-Hall, Inc. A Division of Simon & Schuster Englewood Cliffs, New Jersey 07632 No part of this publication may be reproduced or transmitted in any form or by any means-graphic, electronic, electrical, mechanical, or chemical, including photocopying, recording in any medium, tap­ ing, by any computer or information storage and retrieval systems, etc., without prior permissions in writing from AT&T. IMPORTANT NOTE TO USERS While every effort has been made to ensure the accuracy of all information in this document, AT&T assumes no liability to any party for any loss or damage caused by errors or omissions or by state­ ments of any kind in this document, its updates, supplements, or special editions, whether such er­ rors are omissions or statements resulting from negligence, accident, or any other cause. 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PostScript is a registered trademark of Adobe Systems, Inc. UNIX is a registered trademark of AT&T. VAX is a trademark of Digital Equipment Corporation. XEN IX is a registered trademark of Microsoft Corporation. 10 9 8 7 6 5 4 3 2 1 ISBN 0-13-933821-7 UNIX PRESS A Prentice Hall Title PRE N T C E HAL L ORDERING INFORMATION UNIX@ SYSTEM V, RELEASE 4 DOCUMENTATION To order single copies of UNIX@ SYSTEM V, Release 4 documentation, please call (201) 767-5937. ATTENTION DOCUMENTATION MANAGERS AND TRAINING DIRECTORS: For bulk purchases in excess of 30 copies please write to: Corporate Sales Prentice Hall Englewood Cliffs, N.J. 07632. Or call: (201) 592-2498. ATTENTION GOVERNMENT CUSTO~ERS: For GSA and other pricing information please call (201) 767-5994. Prentice-Hall International (UK) Limited, London Prentice-Hall of Australia Pty. 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Ltd., Singapore Editora Prentice-Hall do BraSil, Ltda., Rio de Janeiro ® AT&T UNIX System V Release 4 General Use and System Administration UNIX® System V Release 4 Network User's and Administrator's Guide UNIX® System V Release 4 Product Overview and Master Index UNIX® System V Release 4 System Administrator's Guide lit UNIX System V Release 4 System Administrator's Reference Manual UNIX® System V Release 4 User's Guide UNIX® System V Release 4 User's Reference Manual General Programmer's Series UNIX® System V Release 4 Programmer's Guide: ANSI C and Programming Support Tools UNIX® System V Release 4 Programmer's Guide: Character User Interface (FMLI and ETI) UNIX® System V Release 4 Programmer's Guide: Networking Interfaces UNIX® System V Release 4 Programmer's Guide: POSIX Conformance UNIX® System V Release 4 Programmer's Guide: System Services and Application Packaging Tools UNIX® System V Release 4 Programmer's Reference Manual System Programmer's Series UNIX® System V Release 4 ANSI C Transition Guide UNIX® System V Release 4 BSD / XENIX® Compatibility Guide UNIX® System V Release 4 Device Driver Interface / Driver-Kernel Interface (DOl/OK!) Reference Manual UNIX® System V Release 4 Migration Guide UNIX® System V Release 4 Programmer's Guide: STREAMS Available from Prentice Hall Ii Contents About This Guide 1 Introduction 1-1 The Evolution of UNIX System V 2 Introduction 2-1 Migrating from Release 2 3 Introduction 3-1 Release 2.0 Features 3-2 Release 2.1 Features 3-4 Migrating from Release 3 4 Introduction 4-1 Release 3.0 Features 4-2 Release 3.1 Features 4-7 Release 3.2 Features 4-11 UNIX System V Release 4 5 Introduction 5-1 The Command Set 5-3 The Command Interface 5-6 File Operations 5-7 The File System 5-9 The Directory Tree 5-14 Table of Contents Table of Contents _______________________ InpuVOutput 5-21 Memory Management 5-23 System Access 5-25 Process Management 5-27 System Administration and Maintenance 5-30 Networking 5-32 Character-Based User Interfaces 5-38 Graphical User Interface 5-39 Internationalization 5-41 C Language 5-44 II Migration Guide Introduction Many of the features introduced in earlier UNIX® System V releases exist unchanged in Release 4.0. Other features have been enhanced, sometimes gra­ dually over a number of releases, to the point where a user may need to become reacquainted with a feature and to explore its capabilities as they exist in Release 4.0. Some features introduced in earlier releases have been replaced altogether by new technology. This guide describes UNIX System V Release 4.0 to the user who is upgrading from an earlier release of UNIX System V. It describes changes that have been made to the system as it has evolved to meet the growing needs of the UNIX system marketplace. Chapter 1, "About this Guide" describes the audience and scope of the Migra­ tion Guide. Chapter 2, "The Evolution of UNIX System V," briefly describes the history of the UNIX system so that the goals of Release 4.0 can be understood in context. Chapter 3, "Migrating from Release 2," describes UNIX System V Release 2 and explains how the features introduced in Releases 2.0 and 2.1 have evolved through Release 3 to their present state in Release 4.0. Users upgrading from a Release 3 system can ignore Chapter 3. Chapter 4, "Migrating from Release 3," describes features introduced in Release 3.0,3.1, and 3.2. Users upgrading from a Release 2 system should read Chapter 4, as many of the features introduced in Release 3 are important features in Release 4.0. Chapter 5, "UNIX System V Release 4.0," describes Release 4.0. The scope of Release 4.0 exceeds the scope of earlier releases and constitutes a redesign of some aspects of the system. Therefore, the description of Release 4.0 in Chapter 5 is not presented as a list of new features. Instead, it examines functional areas of the system, describes these functional areas as they existed in earlier UNIX System V releases, then describes the changes made in each functional area in Release 4.0. Discussion of new features is integrated into the discussion of func­ tional areas. For example, a section entitled "System Access" describes the method for accessing a UNIX system running an earlier release of UNIX System V, then describes the architectural changes made in Release 4.0 to provide a con­ sistent access mechanism for both local and network users. For a listing of Release 4.0 features, followed by a description of each new feature, see the "Pro­ duct Overview" at the beginning of the Product Overview and Master Index. About This Guide 1-1 Introduction The UNIX system is an evolving system. Developed at Bell Laboratories in the 1960s, the UNIX system was strictly an internal system until AT&T began licens­ ing it in the early 1970s. As a non-proprietary system, the UNIX system was distributed freely-primarily to universities, but also to equipment vendors who enhanced the system to meet the needs of their hardware. Many versions of the system began to appear, all with the same basic design, but with differences resulting from the different implementations. In the mid-1970s, the first commercial implementation of the UNIX system appeared. Soon afterward, Microsoft Corporation introduced the XENIX® Sys­ tern. In the academic and military worlds, an implementation of the system developed at the University of California at Berkeley became standard on the DEC VAX line of computers. From Berkeley's implementations (4.1,4.2, and 4.3 BSD), other versions evolved, including Sun Microsystems' SunOS and many of the microprocessor-based versions available today. Following a court-ordered divestiture in 1983, AT&T was allowed to enter the computer industry and market the operating system originally developed in its own laboratories. AT&T's first commercial implementation of the UNIX system was called UNIX System III. By 1984, UNIX System III had evolved into UNIX System V. To date, there have been three major releases of UNIX System V: Release 2, Release 3, and, now, Release 4. Each release provides features that extend the power, the usefulness, and the usability of the UNIX system. The Evolution of UNIX System V 2-1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 3 Migrating from Release 2 Introduction 3-1 Release 2.0 Features 3-2 SeH-Configuration 3-2 Dynamic Disk Partitioning 3-2 File System Hardening 3-2 Advisory File and Record Locking 3-3 Shell Enhancements (Job Control) 3-3 System Administration/ Menus (sysadm) 3-3 Release 2.1 Features 3-4 Demand Paging 3-4 Mandatory File and Record Locking 3-4 Table of Contents Introduction UNIX System V Release 2 comprised two major releases, which introduced new features, and several maintenance releases.