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~11IIMUNIF
71~0.'
THE DESIGN OF THE UN X
OPERATING SYSTEM
Maurice J. Bach
, Copyright * 1986 by Bell Telephone Laboratories, Incorporated.
Published by Prentice-Hall, Inc.
A division of Simon & Schuster
Englewood Cliffs, New Jersey 07632
Prentice-Hall Software Series
Brian W. Kernighan, Advisor
This edition may he sold only in those countries to which it is
consigned by Prentice-Hall International. It is not to be re-
exported and it is not for sale in the U.S.A., Mexico or Canada.
UNIXO° is a registered trademark of AT&T.
DEC, PDR and VAX are trademarks of Digital Equipment Corp.
Series 32000 is a trademark of National Semiconductor Corp.
g
Ada is a registered trademark of the U.S. Government (Ada Joint Program Office).
UNIVAC is a trademark of Sperry Corp.
This document was set on an AUTOLOGIC, Inc. APS-5 phototypesetter driven by the
TROFF formatter operating under the UNIX system on an AT&T 3B20 computer.
The author and publisher of this book have used their best efforts in preparing
this book. These efforts include the development, research, and testing of the
theories and programs to determine their effectiveness. The author and
publisher make no warranty of any kind, expressed or implied, with regard to
these programs or the documentation contained in this book. The author and
publisher shall not be liable in any event for incidental or consequential
damages in connection with, or arising out of, the furnishing, performance, or
use of these programs.
All rights reserved. No part of this book may be
reproduced, in any form or by any mean&
without permission in writing from the publisher
Printed in the United States of America
10 9 8 7
ISBN 0 -13-201757-1 025
P
P
rentice-Hall International (UK) Limited, London
P
rentice-Hall of Australia Pty. Limited, Sydney
P
rentice-Hall Canada Inc., Toronto
H p
rentice-Hall is anoamericana, S.A., Mexico
P
P
rentice-Hall of India Private Limited, New Delhi
P
rentice-Hall of Japan, Inc., Tokyo
rentice-Hall of Southeast Asia Pte. Ltd., Singapore
Editora Prentice-Hall do Brasil, Ltda., Rio de Janeiro
Pr
entice-Hall, Inc., Englewood Cliffs, New Jersey
, To nv parents, for their patience and devotion,
to my daughters, Sarah and Rachel, for their laughter,
to my son, Joseph, who arrived after the first printing,
and to my wife, Debby, for her love and understanding.
, CONTENTS
PREFACE .............................................................................................................
CHAPTER 1 GENERAL OVERVIEW OF THE SYSTEM ..................... 1
........
1.1 HISTORY ........................................................................................ 1
1.2 SYSTEM STRUCTURE .............................................................. 4
1.3 USER PERSPECTIVE .................................................................... 6
1.4 OPERATING SYSTEM SERVICES .......................................... 14
1.5 ASSUMPTIONS ABOUT HARDWARE 15
1.6 SUMMARY ................................................................................... 18
~11IIMUNIF
71~0.'
THE DESIGN OF THE UN X
OPERATING SYSTEM
Maurice J. Bach
, Copyright * 1986 by Bell Telephone Laboratories, Incorporated.
Published by Prentice-Hall, Inc.
A division of Simon & Schuster
Englewood Cliffs, New Jersey 07632
Prentice-Hall Software Series
Brian W. Kernighan, Advisor
This edition may he sold only in those countries to which it is
consigned by Prentice-Hall International. It is not to be re-
exported and it is not for sale in the U.S.A., Mexico or Canada.
UNIXO° is a registered trademark of AT&T.
DEC, PDR and VAX are trademarks of Digital Equipment Corp.
Series 32000 is a trademark of National Semiconductor Corp.
g
Ada is a registered trademark of the U.S. Government (Ada Joint Program Office).
UNIVAC is a trademark of Sperry Corp.
This document was set on an AUTOLOGIC, Inc. APS-5 phototypesetter driven by the
TROFF formatter operating under the UNIX system on an AT&T 3B20 computer.
The author and publisher of this book have used their best efforts in preparing
this book. These efforts include the development, research, and testing of the
theories and programs to determine their effectiveness. The author and
publisher make no warranty of any kind, expressed or implied, with regard to
these programs or the documentation contained in this book. The author and
publisher shall not be liable in any event for incidental or consequential
damages in connection with, or arising out of, the furnishing, performance, or
use of these programs.
All rights reserved. No part of this book may be
reproduced, in any form or by any mean&
without permission in writing from the publisher
Printed in the United States of America
10 9 8 7
ISBN 0 -13-201757-1 025
P
P
rentice-Hall International (UK) Limited, London
P
rentice-Hall of Australia Pty. Limited, Sydney
P
rentice-Hall Canada Inc., Toronto
H p
rentice-Hall is anoamericana, S.A., Mexico
P
P
rentice-Hall of India Private Limited, New Delhi
P
rentice-Hall of Japan, Inc., Tokyo
rentice-Hall of Southeast Asia Pte. Ltd., Singapore
Editora Prentice-Hall do Brasil, Ltda., Rio de Janeiro
Pr
entice-Hall, Inc., Englewood Cliffs, New Jersey
, To nv parents, for their patience and devotion,
to my daughters, Sarah and Rachel, for their laughter,
to my son, Joseph, who arrived after the first printing,
and to my wife, Debby, for her love and understanding.
, CONTENTS
PREFACE .............................................................................................................
CHAPTER 1 GENERAL OVERVIEW OF THE SYSTEM ..................... 1
........
1.1 HISTORY ........................................................................................ 1
1.2 SYSTEM STRUCTURE .............................................................. 4
1.3 USER PERSPECTIVE .................................................................... 6
1.4 OPERATING SYSTEM SERVICES .......................................... 14
1.5 ASSUMPTIONS ABOUT HARDWARE 15
1.6 SUMMARY ................................................................................... 18
