1<html> 2<title> 3preface4 4</title> 5<body BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#330088" ALINK="#FF0044"> 6<H1>Preface to the Fourth (2002) Edition 7</H1> 8<br> <br> 9Plan 9 continues to grow and adapt. 10The fourth major release of the system 11incorporates a number of changes, but the most central 12is the conversion to a new version of the 9P file system 13protocol. 14This new version was motivated by a desire to support 15files with name elements longer than 27 bytes (the old 16<TT>NAMELEN</TT>), 17but the opportunity was taken to change a number of other things 18about the protocol, 19making it more efficient, more flexible, and easier to encapsulate. 20One simple but indispensable new feature made possible by the protocol 21change is that the system now records the user who last modified a file; 22try 23<TT>ls</TT> 24<TT>-m</TT> 25to identify the culprit. 26<br> <br> 27Many aspects of system security have been improved. 28The new security agent 29<A href="/magic/man2html/4/factotum"><I>factotum</I>(4) 30</A>maintains user passwords, while 31<A href="/magic/man2html/8/secstore"><I>secstore</I>(8) 32</A>keeps them safe and enables single sign-on to multiple domains and machines 33using a variety of secure protocols and services. 34<br> <br> 35Throughout the system, components have been rewritten and interfaces 36modified to eliminate restrictions, improve performance, and clarify design. 37The full list is too long to include here, but significant changes have occurred 38in a number of system calls 39<A href="/magic/man2html/2/wait">(<I>wait</I>(2), 40</A><A href="/magic/man2html/2/stat"><I>stat</I>(2), 41</A><A href="/magic/man2html/2/mount"><I>mount</I>(2), 42</A>and 43<A href="/magic/man2html/2/errstr"><I>errstr</I>(2)), 44</A>the thread library 45<A href="/magic/man2html/2/thread">(<I>thread</I>(2)), 46</A>formatted printing 47<A href="/magic/man2html/2/print">(<I>print</I>(2) 48</A>and 49<A href="/magic/man2html/2/fmtinstall"><I>fmtinstall</I>(2)), 50</A>security 51(many pages in section 2, including 52<A href="/magic/man2html/2/auth"><I>auth</I>(2), 53</A><A href="/magic/man2html/2/authsrv"><I>authsrv</I>(2)), 54</A>and many others. 55<br> <br> 56The changes are sweeping and are accompanied by many new programs, tools, 57services, 58and libraries. 59See the manual pages and the accompanying documents for more information. 60<br> <br> 61<br> <br> 62<DL><DT><DD> 63<DL><DT><DD> 64<DL><DT><DD> 65<DL><DT><DD> 66<DL><DT><DD> 67<DL><DT><DD> 68Bell Labs 69<br> 70Computing Science Research Center 71<br> 72Murray Hill NJ 73<br> 74April, 2002 75<br> <br> 76<A href=http://www.lucent.com/copyright.html> 77Copyright</A> © 2002 Lucent Technologies Inc. All rights reserved. 78</body></html> 79