.HTML "Plan 9 — Fourth Edition Release Notes.TLPlan 9 From Bell Labs.brFourth Release Notes.brApril, 2002.brupdated June, 2003.LP.sp -.4i.nf.ce 1000Copyright © 2002-2003 Lucent Technologies Inc.All Rights Reserved.sp .2i.fi.LPThe fourth release of the Plan 9 operating system from Bell Labspackages 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 modifiedand, in many cases, redesigned or rewritten..LPThe most significant change is that 9P has been redesigned to addressa number of shortcomings, most important, its previous inability to handle longfile names.Unfortunately, squeezing long names onto the disks of existingfile servers is a messy business that we're still grappling with,so at the moment.I fs (4)and.I kfs (4)can't yet handle long names,although they do talk the new protocol.(In fact, theytalk both old and new, as required, to ease transition.)In the meantime, there is a workaround \(em.I lnfs (4)\(emand many of the other file servers such as.I ramfs (4)and.I u9fs (4)work just fine with long names.It's only the old disk-resident file serversthat don't.The new file server.I fossil (4)handles supports long names and many other features.The older servers are now deprecated..LPThe following is a partial list of the major changes throughout the system..de Xx.LP\(bu...XxThe file system protocol, 9P, has been reworked.It now has variable-length names, so it can handle long namesbut also is more compact when handling short ones.It uses a different format that is easily parsed, eliminating the need for the old.CW aux/fcallutility,and delegates its authentication duties to an external agent,.CW factotum ..XxSecurity has been a focus of attention.A new security agent,.I factotum (4),manages passwords and other secrets and, coupled with a new secure file store.I secstore (8),enables secure single sign-on..Xx.CW Cpu ,.CW import ,and.CW exportfsall encrypt their connections now, and since they use the new 9P theyalso use new network port numbers.A new service.I aan (1)is used by.CW importto 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.I srvold9p (4)..XxWe are phasing out the IL protocol since it doesn't handle long-distance connectionswell (and long-distance networks don't handle it well, either).IL is still used by.I fs (4)but TCP has become the standard protocol for all other services..XxThe software for the new network-resident secure block store,.I venti (8),is included with this distribution.The newfile server.I fossil (4)uses Venti rather than a WORM as its permanent block repository/backup medium.It is still being developed, but is mature enough that a handful of usersthroughout the world are using it as their primary file server..XxThe need to handle longer file names triggered a rethinking of the way thesystem handles strings in general.The kernel is now more explanatory when it gives an error message andmore consistent in how it handles strings such as commands to devices.The interfaces to many of the system calls, such as.I errstr (2)and.I wait (2)all had to change as a result, as did the library interface to read directories,.I stat (2)and its relatives..XxThe formatted I/O package described in.I print (2)and.I fmtinstall (2)has been redesigned.Although the basic interface is unchanged, it now runs without locks andhas an internal buffer management mechanism that means.CW printno longer needs a large on-stack buffer.The interface for writing custom print verbs and custom formatted I/O routineshas also been greatly improved..XxThe thread library.I thread (2)has been completely rewritten.The main visible change is that, coupled with the changes to printing,.CW threadprintis gone; you can just use.CW printor.CW fprintat will..XxSupport for electronic mail has been extended in many ways and now includessome new spam filtering tools,much better (and more standard) handling of MIME messages,the ability to render incoming HTML mail,and much more..LPThere are so many changes to the programming interfaces of the systemthat they are described in a separate document, entitled.IChanges to the Programming Environment in the Fourth Release of Plan 9..RPlease read it before you start updating your own software to run under the new system..LPThe installation method has also changed and we're moving towards a newmethod for maintaining updates.The Plan 9 Wiki.CW http://plan9.bell-labs.com/wiki/plan9 ) (and Usenet group.CW 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..LPThere's lots more new stuff.If you have problems, mail.CW 9trouble@plan9.bell-labs.comor, better, check the wiki.CW http://plan9.bell-labs.com/wiki/plan9or ask the Usenet newsgroup.CW comp.os.plan9 ..LPGood Luck!