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  6. <H1>Plan 9 From Bell Labs
  7. <br>
  8. Fourth Release Notes
  9. <br>
  10. April, 2002
  11. </H1>
  12. <br>&#32;<br>
  13. <DL><DT><DD><TT><PRE>
  14. Copyright &#169; 2002 Lucent Technologies Inc.
  15. All Rights Reserved
  16. <br>&#32;<br>
  17. </PRE></TT></DL>
  18. <br>&#32;<br>
  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.
  24. <br>&#32;<br>
  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
  27. file names.
  28. Unfortunately, squeezing long names onto the disks of existing
  29. file servers is a messy business that we're still grappling with,
  30. so at the moment
  31. <A href="/magic/man2html/4/fs"><I>fs</I>(4)
  32. </A>and
  33. <A href="/magic/man2html/4/kfs"><I>kfs</I>(4)
  34. </A>can't yet handle long names,
  35. although they do talk the new protocol.
  36. (In fact, they
  37. talk both old and new, as required, to ease transition.)
  38. In the meantime, there is a workaround &#173;
  39. <A href="/magic/man2html/4/lnfs"><I>lnfs</I>(4)
  40. </A>&#173;
  41. and many of the other file servers such as
  42. <A href="/magic/man2html/4/ramfs"><I>ramfs</I>(4)
  43. </A>and
  44. <A href="/magic/man2html/4/u9fs"><I>u9fs</I>(4)
  45. </A>work just fine with long names.
  46. It's only the standard disk-resident file servers
  47. that don't, and as soon we have versions that do, we'll release them.
  48. <br>&#32;<br>
  49. The following is a partial list of the major changes throughout the system.
  50. <br>&#32;<br>
  51. *
  52. The file system protocol, 9P, has been reworked.
  53. It now has variable-length names, so it can handle long names
  54. but also is more compact when handling short ones.
  55. It uses a different format that is easily parsed, eliminating the need for the old
  56. <TT>aux/fcall</TT>
  57. utility,
  58. and delegates its authentication duties to an external agent,
  59. <TT>factotum</TT>.
  60. <br>&#32;<br>
  61. *
  62. Security has been a focus of attention.
  63. A new security agent,
  64. <A href="/magic/man2html/4/factotum"><I>factotum</I>(4),
  65. </A>manages passwords and other secrets and, coupled with a new secure file store
  66. <A href="/magic/man2html/4/secstore"><I>secstore</I>(4),
  67. </A>enables secure single sign-on.
  68. <br>&#32;<br>
  69. *
  70. <TT>Cpu</TT>,
  71. <TT>import</TT>,
  72. and
  73. <TT>exportfs</TT>
  74. all encrypt their connections now, and since they use the new 9P they
  75. also use new network port numbers.
  76. A new service
  77. <A href="/magic/man2html/1/aan"><I>aan</I>(1)
  78. </A>is used by
  79. <TT>import</TT>
  80. to make its network connections more reliable in the face of network outages.
  81. The old ports still work, through the agency of a protocol conversion filter
  82. <A href="/magic/man2html/4/srvold9p"><I>srvold9p</I>(4).
  83. </A><br>&#32;<br>
  84. *
  85. We are phasing out the IL protocol since it doesn't handle long-distance connections
  86. well (and long-distance networks don't handle it well, either).
  87. IL is still used by
  88. <A href="/magic/man2html/4/fs"><I>fs</I>(4)
  89. </A>(in time, that too will change)
  90. but TCP has become the standard protocol for all other services.
  91. <br>&#32;<br>
  92. *
  93. The software for the new network-resident secure block store,
  94. <A href="/magic/man2html/8/venti"><I>venti</I>(8),
  95. </A>is included with this distribution.
  96. We are in the process of reworking
  97. <A href="/magic/man2html/4/fs"><I>fs</I>(4)
  98. </A>to use Venti rather than a WORM as its permanent block repository/backup medium,
  99. but that code is only in the design stage and is not included in this release.
  100. <br>&#32;<br>
  101. *
  102. The need to handle longer file names triggered a rethinking of the way the
  103. system handles strings in general.
  104. The kernel is now more explanatory when it gives an error message and
  105. more consistent in how it handles strings such as commands to devices.
  106. The interfaces to many of the system calls, such as
  107. <A href="/magic/man2html/2/errstr"><I>errstr</I>(2)
  108. </A>and
  109. <A href="/magic/man2html/2/wait"><I>wait</I>(2)
  110. </A>all had to change as a result, as did the library interface to read directories,
  111. <A href="/magic/man2html/2/stat"><I>stat</I>(2)
  112. </A>and its relatives.
  113. <br>&#32;<br>
  114. *
  115. The formatted I/O package described in
  116. <A href="/magic/man2html/2/print"><I>print</I>(2)
  117. </A>and
  118. <A href="/magic/man2html/2/fmtinstall"><I>fmtinstall</I>(2)
  119. </A>has been redesigned.
  120. Although the basic interface is unchanged, it now runs without locks and
  121. has an internal buffer management mechanism that means
  122. <TT>print</TT>
  123. no longer needs a large on-stack buffer.
  124. The interface for writing custom print verbs and custom formatted I/O routines
  125. has also been greatly improved.
  126. <br>&#32;<br>
  127. *
  128. The thread library
  129. <A href="/magic/man2html/2/thread"><I>thread</I>(2)
  130. </A>has been completely rewritten.
  131. The main visible change is that, coupled with the changes to printing,
  132. <TT>threadprint</TT>
  133. is gone; you can just use
  134. <TT>print</TT>
  135. or
  136. <TT>fprint</TT>
  137. at will.
  138. <br>&#32;<br>
  139. *
  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,
  144. and much more.
  145. <br>&#32;<br>
  146. There are so many changes to the programming interfaces of the system
  147. that they are described in a separate document, entitled
  148. Changes to the Programming Environment in the Fourth Release of Plan 9.
  149. Please read it before you start updating your own software to run under the new system.
  150. <br>&#32;<br>
  151. There's lots more.
  152. If you have problems, mail
  153. <TT>9trouble@plan9.bell-labs.com</TT>
  154. or, better, ask the Usenet newsgroup
  155. <TT>comp.os.plan9</TT>.
  156. Please don't mail us individually.
  157. <br>&#32;<br>
  158. Good Luck!
  159. <br>&#32;<br>
  160. <A href=http://www.lucent.com/copyright.html>
  161. Copyright</A> &#169; 2002 Lucent Technologies Inc. All rights reserved.
  162. </body></html>