[9fans] Fourth Release of Plan 9 Now Available

["rob pike, esq." <rob@plan9.bell-labs.com>]

The Fourth Edition of Plan 9 may now be downloaded from

	http://plan9.bell-labs.com/plan9dist

As usual, this is an open source release.  The release
notes summarize the changes; a copy is attached but
they are available in other formats at:

    http://plan9.bell-labs.com/sys/doc/release4.html
    http://plan9.bell-labs.com/sys/doc/release4.ps
    http://plan9.bell-labs.com/sys/doc/release4.pdf


====



               Plan 9 From Bell Labs
               Fourth Release Notes
                   April, 2002


      Copyright (C) 2002 Lucent Technologies Inc.
                All Rights Reserved


The fourth release of the Plan 9 operating system from Bell
Labs packages a major overhaul of the system at every level.
 From the underlying file system protocol, 9P, through the
kernel, libraries, and applications, almost everything has
been modified and, in many cases, redesigned or rewritten.

The most significant change is that 9P has been redesigned
to address a number of shortcomings, most important, its
previous inability to handle long file names.  Unfortu-
nately, squeezing long names onto the disks of existing file
servers is a messy business that we're still grappling with,
so at the moment fs(4) and kfs(4) can't yet handle long
names, although they do talk the new protocol.  (In fact,
they talk both old and new, as required, to ease transi-
tion.) In the meantime, there is a workaround - lnfs(4) -
and many of the other file servers such as ramfs(4) and
u9fs(4) work just fine with long names.  It's only the stan-
dard disk-resident file servers that don't, and as soon we
have versions that do, we'll release them.

The following is a partial list of the major changes
throughout the system.

* The file system protocol, 9P, has been reworked.  It now
has variable-length names, so it can handle long names but
also is more compact when handling short ones.  It uses a
different format that is easily parsed, eliminating the need
for the old aux/fcall utility, and delegates its authenti-
cation duties to an external agent, factotum.

* Security has been a focus of attention.  A new security
agent, factotum(4), manages passwords and other secrets
and, coupled with a new secure file store secstore(4),
enables secure single sign-on.

* Cpu, import, and exportfs all encrypt their connections
now, and since they use the new 9P they also use new network
port numbers.  A new service aan(1) is used by import to
make its network connections more reliable in the face of
network outages.  The old ports still work, through the
agency of a protocol conversion filter srvold9p(4).

* We are phasing out the IL protocol since it doesn't handle
long-distance connections well (and long-distance networks
don't handle it well, either).  IL is still used by fs(4)
(in time, that too will change) but TCP has become the stan-
dard protocol for all other services.

* The software for the new network-resident secure block
store, venti(8), is included with this distribution.  We
are in the process of reworking fs(4) to use Venti rather
than a WORM as its permanent block repository/backup medium,
but that code is only in the design stage and is not
included in this release.

* The need to handle longer file names triggered a rethink-
ing of the way the system handles strings in general.  The
kernel is now more explanatory when it gives an error mes-
sage and more consistent in how it handles strings such as
commands to devices.  The interfaces to many of the system
calls, such as errstr(2) and wait(2) all had to change as
a result, as did the library interface to read directories,
stat(2) and its relatives.

* The formatted I/O package described in print(2) and
fmtinstall(2) has been redesigned.  Although the basic
interface is unchanged, it now runs without locks and has an
internal buffer management mechanism that means print no
longer needs a large on-stack buffer.  The interface for
writing custom print verbs and custom formatted I/O routines
has also been greatly improved.

* The thread library thread(2) has been completely rewrit-
ten.  The main visible change is that, coupled with the
changes to printing, threadprint is gone; you can just use
print or fprint at will.

* Support for electronic mail has been extended in many ways
and now includes some new spam filtering tools, much better
(and more standard) handling of MIME messages, the ability
to render incoming HTML mail, and much more.

There are so many changes to the programming interfaces of
the system that they are described in a separate document,
entitled Changes to the Programming Environment in the
Fourth Release of Plan 9.  Please read it before you start
updating your own software to run under the new system.

The installation method has also changed and we're moving
towards a new method for maintaining updates.  The Plan 9
Wiki (http://plan9.bell-labs.com/wiki/plan9) and Usenet
group (comp.os.plan9) are the places to visit to learn more
and stay current.  In particular, the installation notes are
now maintained in the Wiki; the traditional papers on
installation and start-up are gone.

There's lots more new stuff.  If you have problems, mail
9trouble@plan9.bell-labs.com or, better, check the wiki
http://plan9.bell-labs.com/wiki/plan9 or ask the Usenet
newsgroup comp.os.plan9.

Good Luck!