5 <body BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#330088" ALINK="#FF0044">
6 <H1>Preface to the Fourth (2002) Edition
9 Plan 9 continues to grow and adapt.
10 The fourth major release of the system
11 incorporates a number of changes, but the most central
12 is the conversion to a new version of the 9P file system
14 This new version was motivated by a desire to support
15 files with name elements longer than 27 bytes (the old
17 but the opportunity was taken to change a number of other things
19 making it more efficient, more flexible, and easier to encapsulate.
20 One simple but indispensable new feature made possible by the protocol
21 change is that the system now records the user who last modified a file;
25 to identify the culprit.
27 Many aspects of system security have been improved.
28 The 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
33 using a variety of secure protocols and services.
35 Throughout the system, components have been rewritten and interfaces
36 modified to eliminate restrictions, improve performance, and clarify design.
37 The full list is too long to include here, but significant changes have occurred
38 in 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),
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)
49 <A href="/magic/man2html/2/fmtinstall"><I>fmtinstall</I>(2)),
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)),
56 The changes are sweeping and are accompanied by many new programs, tools,
59 See the manual pages and the accompanying documents for more information.
70 Computing Science Research Center
76 <A href=http://www.lucent.com/copyright.html>
77 Copyright</A> © 2002 Lucent Technologies Inc. All rights reserved.