1 .HTML "Plan 9 — Fourth Edition Release Notes
14 Copyright © 2002-2003 Lucent Technologies Inc.
19 The fourth release of the Plan 9 operating system from Bell Labs
20 packages a major overhaul of the system at every level.
21 From the underlying file system protocol, 9P, through the kernel,
22 libraries, and applications, almost everything has been modified
23 and, in many cases, redesigned or rewritten.
25 The most significant change is that 9P has been redesigned to address
26 a number of shortcomings, most important, its previous inability to handle long
28 Unfortunately, squeezing long names onto the disks of existing
29 file servers is a messy business that we're still grappling with,
34 can't yet handle long names,
35 although they do talk the new protocol.
37 talk both old and new, as required, to ease transition.)
38 In the meantime, there is a workaround \(em
41 and many of the other file servers such as
45 work just fine with long names.
46 It's only the old disk-resident file servers
50 handles supports long names and many other features.
51 The older servers are now deprecated.
53 The following is a partial list of the major changes throughout the system.
59 The file system protocol, 9P, has been reworked.
60 It now has variable-length names, so it can handle long names
61 but also is more compact when handling short ones.
62 It uses a different format that is easily parsed, eliminating the need for the old
65 and delegates its authentication duties to an external agent,
68 Security has been a focus of attention.
71 manages passwords and other secrets and, coupled with a new secure file store
73 enables secure single sign-on.
79 all encrypt their connections now, and since they use the new 9P they
80 also use new network port numbers.
85 to make its network connections more reliable in the face of network outages.
86 The old ports still work, through the agency of a protocol conversion filter
89 We are phasing out the IL protocol since it doesn't handle long-distance connections
90 well (and long-distance networks don't handle it well, either).
93 but TCP has become the standard protocol for all other services.
95 The software for the new network-resident secure block store,
97 is included with this distribution.
101 uses Venti rather than a WORM as its permanent block repository/backup medium.
102 It is still being developed, but is mature enough that a handful of users
103 throughout the world are using it as their primary file server.
105 The need to handle longer file names triggered a rethinking of the way the
106 system handles strings in general.
107 The kernel is now more explanatory when it gives an error message and
108 more consistent in how it handles strings such as commands to devices.
109 The interfaces to many of the system calls, such as
113 all had to change as a result, as did the library interface to read directories,
117 The formatted I/O package described in
122 Although the basic interface is unchanged, it now runs without locks and
123 has an internal buffer management mechanism that means
125 no longer needs a large on-stack buffer.
126 The interface for writing custom print verbs and custom formatted I/O routines
127 has also been greatly improved.
131 has been completely rewritten.
132 The main visible change is that, coupled with the changes to printing,
134 is gone; you can just use
140 Support for electronic mail has been extended in many ways and now includes
141 some new spam filtering tools,
142 much better (and more standard) handling of MIME messages,
143 the ability to render incoming HTML mail,
146 There are so many changes to the programming interfaces of the system
147 that they are described in a separate document, entitled
149 Changes to the Programming Environment in the Fourth Release of Plan 9.
151 Please read it before you start updating your own software to run under the new system.
153 The installation method has also changed and we're moving towards a new
154 method for maintaining updates.
156 .CW http://plan9.bell-labs.com/wiki/plan9 ) (
158 .CW comp.os.plan9 ) (
159 are the places to visit to learn more and stay current.
160 In particular, the installation notes are now maintained in the Wiki;
161 the traditional papers on installation and start-up are gone.
163 There's lots more new stuff.
164 If you have problems, mail
165 .CW 9trouble@plan9.bell-labs.com
166 or, better, check the wiki
167 .CW http://plan9.bell-labs.com/wiki/plan9
168 or ask the Usenet newsgroup