1<html> 2<title> 3preface 4</title> 5<body BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#330088" ALINK="#FF0044"> 6<H1>Preface to the Second (1995) Edition 7</H1> 8<P> 9Plan 9 was born in the same lab where Unix began. 10Old Unix hands will recognize the cultural heritage in this manual, 11where venerable Unix commands live on, 12described in the classic Unix style. Underneath, though, lies 13a new kind of system, organized around communication and 14naming rather than files and processes. 15</P> 16<P> 17In Plan 9, distributed computing is a central premise, 18not an evolutionary add-on. The system relies on a 19uniform protocol to refer to and communicate 20with objects, whether they be data or processes, and whether or 21not they live on the same machine or even similar machines. 22A single paradigm (writing to named places) unifies 23all kinds of control and interprocess signaling. 24</P> 25<P> 26Name spaces can be built arbitrarily. In particular all 27programs available to a given user are customarily united 28in a single logical directory. 29Temporary files and 30untrusted activities can be confined in isolated spaces. 31When a portable machine connects to the 32central, archival file system, the machine's local 33name space is joined smoothly to that of the archival file system. 34The architecture affords other unusual abilities, including: 35</P> 36<DL> 37<DT><DT> <DD> 38Objects in name spaces imported from other machines (even from 39foreign systems such as MS-DOS) are transparently accessible. 40<DT><DT> <DD> 41Windows appear in name spaces on a par with files and processes. 42<DT><DT> <DD> 43A historical file system allows one to navigate 44the archival file system in time as well as in space; 45backup files are always at hand. 46<DT><DT> <DD> 47A debugger can handle simultaneously active processes 48on disparate kinds of hardware. 49</dl> 50<P> 51The character set of Plan 9 is Unicode, which 52covers most of the world's major scripts. 53The system has its own programming languages: 54a dialect of C with simple inheritance, a simplified shell, 55and a CSP-like concurrent language, Alef. 56An ANSI-POSIX emulator (APE) admits unreconstructed Unix code. 57</P> 58<P> 59Plan 9 is the work of many people. 60The protocol was begun by Ken Thompson; naming 61was integrated by Rob Pike and networking by Dave Presotto. 62Phil Winterbottom simplified the management of name spaces 63and re-engineered the system. 64They were joined by Tom Killian, Jim McKie, and Howard Trickey in 65bringing the system up on various machines and making 66device drivers. 67Thompson made the C compiler; 68Pike, window systems; 69Tom Duff, the shell and raster graphics; 70Winterbottom, Alef; 71Trickey, Duff, and Andrew Hume, APE. 72Bob Flandrena ported a myriad of 73programs to Plan 9. 74Other contributors include 75Alan Berenbaum, 76Lorinda Cherry, 77Bill Cheswick, 78Sean Dorward, 79David Gay, 80Paul Glick, 81Eric Grosse, 82John Hobby, 83Gerard Holzmann, 84Brian Kernighan, 85Bart Locanthi, 86Doug McIlroy, 87Judy Paone, 88Sean Quinlan, 89Bob Restrick, 90Dennis Ritchie, 91Bjarne Stroustrup, 92and 93Cliff Young. 94</P> 95<P> 96Plan 9 is made available as is, without formal support, but 97substantial comments or contributions may be communicated to 98the authors. 99<br> <br> 100<DL><DT><DD> 101<DL><DT><DD> 102<DL><DT><DD> 103<DL><DT><DD> 104<DL><DT><DD> 105<DL><DT><DD> 106<DL><DT><DD> 107<DL><DT><DD> 108Doug McIlroy 109<br> 110March, 1995 111 112</P> 113<br> <br> 114<A href=http://www.lucent.com/copyright.html> 115Copyright</A> © 2000 Lucent Technologies Inc. All rights reserved. 116</body></html> 117