path: root/doc/mach.info-2

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INFO-DIR-SECTION Kernel
START-INFO-DIR-ENTRY
* GNUMach: (mach).              Using and programming the GNU Mach microkernel.
END-INFO-DIR-ENTRY

   This file documents the GNU Mach microkernel.

   This is Edition 0.4, last updated 2001-09-01, of `The GNU Mach
Reference Manual', for Version 1.3.99.

   Copyright (C) 2001 Free Software Foundation, Inc.

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Free Software Needs Free Documentation" and
"GNU Lesser General Public License", the Front-Cover texts being (a)
(see below), and with the Back-Cover Texts being (b) (see below).  A
copy of the license is included in the section entitled "GNU Free
Documentation License".

   (a) The FSF's Front-Cover Text is:

   A GNU Manual

   (b) The FSF's Back-Cover Text is:

   You have freedom to copy and modify this GNU Manual, like GNU
software.  Copies published by the Free Software Foundation raise
funds for GNU development.

   This work is based on manual pages under the following copyright and
license:

Mach Operating System
Copyright (C) 1991,1990 Carnegie Mellon University
All Rights Reserved.

   Permission to use, copy, modify and distribute this software and its
documentation is hereby granted, provided that both the copyright
notice and this permission notice appear in all copies of the software,
derivative works or modified versions, and any portions thereof, and
that both notices appear in supporting documentation.

   CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY
DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.


File: mach.info,  Node: Commands,  Next: Variables,  Prev: Operation,  Up: Kernel Debugger

11.2 Commands
=============

`examine(x) [/MODIFIER] ADDR[,COUNT] [ THREAD ]'
     Display the addressed locations according to the formats in the
     modifier.  Multiple modifier formats display multiple locations.
     If no format is specified, the last formats specified for this
     command is used.  Address space other than that of the current
     thread can be specified with `t' option in the modifier and THREAD
     parameter.  The format characters are

    `b'
          look at by bytes(8 bits)

    `h'
          look at by half words(16 bits)

    `l'
          look at by long words(32 bits)

    `a'
          print the location being displayed

    `,'
          skip one unit producing no output

    `A'
          print the location with a line number if possible

    `x'
          display in unsigned hex

    `z'
          display in signed hex

    `o'
          display in unsigned octal

    `d'
          display in signed decimal

    `u'
          display in unsigned decimal

    `r'
          display in current radix, signed

    `c'
          display low 8 bits as a character.  Non-printing characters
          are displayed as an octal escape code (e.g. '\000').

    `s'
          display the null-terminated string at the location.
          Non-printing characters are displayed as octal escapes.

    `m'
          display in unsigned hex with character dump at the end of
          each line.  The location is also displayed in hex at the
          beginning of each line.

    `i'
          display as an instruction

    `I'
          display as an instruction with possible alternate formats
          depending on the machine:

         `vax'
               don't assume that each external label is a procedure
               entry mask

         `i386'
               don't round to the next long word boundary

         `mips'
               print register contents

`xf'
     Examine forward.  It executes an examine command with the last
     specified parameters to it except that the next address displayed
     by it is used as the start address.

`xb'
     Examine backward.  It executes an examine command with the last
     specified parameters to it except that the last start address
     subtracted by the size displayed by it is used as the start
     address.

`print[/axzodurc] ADDR1 [ ADDR2 ... ]'
     Print ADDR's according to the modifier character.  Valid formats
     are: `a' `x' `z' `o' `d' `u' `r' `c'.  If no modifier is
     specified, the last one specified to it is used.  ADDR can be a
     string, and it is printed as it is.  For example,

          print/x "eax = " $eax "\necx = " $ecx "\n"

     will print like

          eax = xxxxxx
          ecx = yyyyyy

`write[/bhlt] ADDR [ THREAD ] EXPR1 [ EXPR2 ... ]'
     Write the expressions at succeeding locations.  The write unit
     size can be specified in the modifier with a letter b (byte), h
     (half word) or l(long word) respectively.  If omitted, long word
     is assumed.  Target address space can also be specified with `t'
     option in the modifier and THREAD parameter.  Warning: since there
     is no delimiter between expressions, strange things may happen.
     It's best to enclose each expression in parentheses.

`set $VARIABLE [=] EXPR'
     Set the named variable or register with the value of EXPR.  Valid
     variable names are described below.

`break[/tuTU] ADDR[,COUNT] [ THREAD1 ... ]'
     Set a break point at ADDR.  If count is supplied, continues
     (COUNT-1) times before stopping at the break point.  If the break
     point is set, a break point number is printed with `#'.  This
     number can be used in deleting the break point or adding
     conditions to it.

    `t'
          Set a break point only for a specific thread.  The thread is
          specified by THREAD parameter, or default one is used if the
          parameter is omitted.

    `u'
          Set a break point in user space address.  It may be combined
          with `t' or `T' option to specify the non-current target user
          space.  Without `u' option, the address is considered in the
          kernel space, and wrong space address is rejected with an
          error message.  This option can be used only if it is
          supported by machine dependent routines.

    `T'
          Set a break point only for threads in a specific task.  It is
          like `t' option except that the break point is valid for all
          threads which belong to the same task as the specified target
          thread.

    `U'
          Set a break point in shared user space address.  It is like
          `u' option, except that the break point is valid for all
          threads which share the same address space even if `t' option
          is specified.  `t' option is used only to specify the target
          shared space.  Without `t' option, `u' and `U' have the same
          meanings.  `U' is useful for setting a user space break point
          in non-current address space with `t' option such as in an
          emulation library space.  This option can be used only if it
          is supported by machine dependent routines.

     Warning: if a user text is shadowed by a normal user space
     debugger, user space break points may not work correctly.  Setting
     a break point at the low-level code paths may also cause strange
     behavior.

`delete[/tuTU] ADDR|#NUMBER [ THREAD1 ... ]'
     Delete the break point.  The target break point can be specified
     by a break point number with `#', or by ADDR like specified in
     `break' command.

`cond #NUMBER [ CONDITION COMMANDS ]'
     Set or delete a condition for the break point specified by the
     NUMBER.  If the CONDITION and COMMANDS are null, the condition is
     deleted.  Otherwise the condition is set for it.  When the break
     point is hit, the CONDITION is evaluated.  The COMMANDS will be
     executed if the condition is true and the break point count set by
     a break point command becomes zero.  COMMANDS is a list of
     commands separated by semicolons.  Each command in the list is
     executed in that order, but if a `continue' command is executed,
     the command execution stops there, and the stopped thread resumes
     execution.  If the command execution reaches the end of the list,
     and it enters into a command input mode.  For example,

          set $work0 0
          break/Tu xxx_start $task7.0
          cond #1  (1)  set $work0 1; set $work1 0; cont
          break/T  vm_fault $task7.0
          cond #2  ($work0) set $work1 ($work1+1); cont
          break/Tu xxx_end $task7.0
          cond #3  ($work0) print $work1 " faults\n"; set $work0 0
          cont

     will print page fault counts from `xxx_start' to `xxx_end' in
     `task7'.

`step[/p] [,COUNT]'
     Single step COUNT times.  If `p' option is specified, print each
     instruction at each step.  Otherwise, only print the last
     instruction.

     Warning: depending on machine type, it may not be possible to
     single-step through some low-level code paths or user space code.
     On machines with software-emulated single-stepping (e.g., pmax),
     stepping through code executed by interrupt handlers will probably
     do the wrong thing.

`continue[/c]'
     Continue execution until a breakpoint or watchpoint.  If `/c',
     count instructions while executing.  Some machines (e.g., pmax)
     also count loads and stores.

     Warning: when counting, the debugger is really silently
     single-stepping.  This means that single-stepping on low-level
     code may cause strange behavior.

`until'
     Stop at the next call or return instruction.

`next[/p]'
     Stop at the matching return instruction.  If `p' option is
     specified, print the call nesting depth and the cumulative
     instruction count at each call or return.  Otherwise, only print
     when the matching return is hit.

`match[/p]'
     A synonym for `next'.

`trace[/tu] [ FRAME_ADDR|THREAD ][,COUNT]'
     Stack trace.  `u' option traces user space; if omitted, only traces
     kernel space.  If `t' option is specified, it shows the stack trace
     of the specified thread or a default target thread.  Otherwise, it
     shows the stack trace of the current thread from the frame address
     specified by a parameter or from the current frame.  COUNT is the
     number of frames to be traced.  If the COUNT is omitted, all
     frames are printed.

     Warning: If the target thread's stack is not in the main memory at
     that time, the stack trace will fail.  User space stack trace is
     valid only if the machine dependent code supports it.

`search[/bhl] ADDR VALUE [MASK] [,COUNT]'
     Search memory for a value.  This command might fail in interesting
     ways if it doesn't find the searched-for value.  This is because
     `ddb' doesn't always recover from touching bad memory.  The
     optional count argument limits the search.

`macro NAME COMMANDS'
     Define a debugger macro as NAME.  COMMANDS is a list of commands
     to be associated with the macro.  In the expressions of the
     command list, a variable `$argxx' can be used to get a parameter
     passed to the macro.  When a macro is called, each argument is
     evaluated as an expression, and the value is assigned to each
     parameter, `$arg1', `$arg2', ... respectively.  10 `$arg'
     variables are reserved to each level of macros, and they can be
     used as local variables.  The nesting of macro can be allowed up
     to 5 levels.  For example,

          macro xinit set $work0 $arg1
          macro xlist examine/m $work0,4; set $work0 *($work0)
          xinit *(xxx_list)
          xlist
          ....

     will print the contents of a list starting from `xxx_list' by each
     `xlist' command.

`dmacro NAME'
     Delete the macro named NAME.

`show all threads[/ul]'
     Display all tasks and threads information.  This version of `ddb'
     prints more information than previous one.  It shows UNIX process
     information like `ps' for each task.  The UNIX process information
     may not be shown if it is not supported in the machine, or the
     bottom of the stack of the target task is not in the main memory at
     that time.  It also shows task and thread identification numbers.
     These numbers can be used to specify a task or a thread
     symbolically in various commands.  The numbers are valid only in
     the same debugger session.  If the execution is resumed again, the
     numbers may change.  The current thread can be distinguished from
     others by a `#' after the thread id instead of `:'.  Without `l'
     option, it only shows thread id, thread structure address and the
     status for each thread.  The status consists of 5 letters, R(run),
     W(wait), S(sus­ pended), O(swapped out) and N(interruptible), and
     if corresponding status bit is off, `.'  is printed instead.  If
     `l' option is specified, more detail information is printed for
     each thread.

`show task [ ADDR ]'
     Display the information of a task specified by ADDR.  If ADDR is
     omitted, current task information is displayed.

`show thread [ ADDR ]'
     Display the information of a thread specified by ADDR.  If ADDR is
     omitted, current thread information is displayed.

`show registers[/tu [ THREAD ]]'
     Display the register set.  Target thread can be specified with `t'
     option and THREAD parameter.  If `u' option is specified, it
     displays user registers instead of kernel or currently saved one.

     Warning: The support of `t' and `u' option depends on the machine.
     If not supported, incorrect information will be displayed.

`show map ADDR'
     Prints the `vm_map' at ADDR.

`show object ADDR'
     Prints the `vm_object' at ADDR.

`show page ADDR'
     Prints the `vm_page' structure at ADDR.

`show port ADDR'
     Prints the `ipc_port' structure at ADDR.

`show ipc_port[/t [ THREAD ]]'
     Prints all `ipc_port' structure's addresses the target thread has.
     The target thread is a current thread or that specified by a
     parameter.

`show macro [ NAME ]'
     Show the definitions of macros.  If NAME is specified, only the
     definition of it is displayed.  Otherwise, definitions of all
     macros are displayed.

`show watches'
     Displays all watchpoints.

`watch[/T] ADDR,SIZE [ TASK ]'
     Set a watchpoint for a region.  Execution stops when an attempt to
     modify the region occurs.  The SIZE argument defaults to 4.
     Without `T' option, ADDR is assumed to be a kernel address.  If
     you want to set a watch point in user space, specify `T' and TASK
     parameter where the address belongs to.  If the TASK parameter is
     omitted, a task of the default target thread or a current task is
     assumed.  If you specify a wrong space address, the request is
     rejected with an error message.

     Warning: Attempts to watch wired kernel memory may cause
     unrecoverable error in some systems such as i386.  Watchpoints on
     user addresses work best.


File: mach.info,  Node: Variables,  Next: Expressions,  Prev: Commands,  Up: Kernel Debugger

11.3 Variables
==============

The debugger accesses registers and variables as $NAME.  Register names
are as in the `show registers' command.  Some variables are suffixed
with numbers, and may have some modifier following a colon immediately
after the variable name.  For example, register variables can have `u'
and `t' modifier to indicate user register and that of a default target
thread instead of that of the current thread (e.g. `$eax:tu').

   Built-in variables currently supported are:

`taskXX[.YY]'
     Task or thread structure address.  XX and YY are task and thread
     identification numbers printed by a `show all threads' command
     respectively.  This variable is read only.

`thread'
     The default target thread.  The value is used when `t' option is
     specified without explicit thread structure address parameter in
     command lines or expression evaluation.

`radix'
     Input and output radix

`maxoff'
     Addresses are printed as SYMBOL+OFFSET unless offset is greater
     than maxoff.

`maxwidth'
     The width of the displayed line.

`lines'
     The number of lines.  It is used by `more' feature.

`tabstops'
     Tab stop width.

`argXX'
     Parameters passed to a macro.  XX can be 1 to 10.

`workXX'
     Work variable.  XX can be 0 to 31.


File: mach.info,  Node: Expressions,  Prev: Variables,  Up: Kernel Debugger

11.4 Expressions
================

Almost all expression operators in C are supported except `~', `^', and
unary `&'.  Special rules in `ddb' are:

`IDENTIFIER'
     name of a symbol.  It is translated to the address(or value) of it.
     `.'  and `:' can be used in the identifier.  If supported by an
     object format dependent routine, [FILE_NAME:]FUNC[:LINE_NUMBER]
     [FILE_NAME:]VARIABLE, and FILE_NAME[:LINE_NUMBER] can be accepted
     as a symbol.  The symbol may be prefixed with
     `SYMBOL_TABLE_NAME::' like `emulator::mach_msg_trap' to specify
     other than kernel symbols.

`NUMBER'
     radix is determined by the first two letters:
    `0x'
          hex

    `0o'
          octal

    `0t'
          decimal

     otherwise, follow current radix.

`.'
     dot

`+'
     next

`..'
     address of the start of the last line examined.  Unlike dot or
     next, this is only changed by `examine' or `write' command.

`´'
     last address explicitly specified.

`$VARIABLE'
     register name or variable.  It is translated to the value of it.
     It may be followed by a `:' and modifiers as described above.

`a'
     multiple of right hand side.

`*EXPR'
     indirection.  It may be followed by a `:' and modifiers as
     described above.


File: mach.info,  Node: Copying,  Next: Documentation License,  Prev: Kernel Debugger,  Up: Top

Appendix A GNU GENERAL PUBLIC LICENSE
*************************************

                         Version 2, June 1991

     Copyright (C) 1989, 1991 Free Software Foundation, Inc.
     59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.

A.0.1 Preamble
--------------

The licenses for most software are designed to take away your freedom
to share and change it.  By contrast, the GNU General Public License is
intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users.  This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it.  (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.)  You can apply it to
your programs, too.

   When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it in
new free programs; and that you know you can do these things.

   To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.

   For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have.  You must make sure that they, too, receive or can get the
source code.  And you must show them these terms so they know their
rights.

   We protect your rights with two steps: (1) copyright the software,
and (2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.

   Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software.  If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
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   Finally, any free program is threatened constantly by software
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     versions of the General Public License from time to time.  Such
     new versions will be similar in spirit to the present version, but
     may differ in detail to address new problems or concerns.

     Each version is given a distinguishing version number.  If the
     Program specifies a version number of this License which applies
     to it and "any later version", you have the option of following
     the terms and conditions either of that version or of any later
     version published by the Free Software Foundation.  If the Program
     does not specify a version number of this License, you may choose
     any version ever published by the Free Software Foundation.

 11. If you wish to incorporate parts of the Program into other free
     programs whose distribution conditions are different, write to the
     author to ask for permission.  For software which is copyrighted
     by the Free Software Foundation, write to the Free Software
     Foundation; we sometimes make exceptions for this.  Our decision
     will be guided by the two goals of preserving the free status of
     all derivatives of our free software and of promoting the sharing
     and reuse of software generally.

                                NO WARRANTY
 12. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO
     WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE
     LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
     HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT
     WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT
     NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
     FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS TO THE
     QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
     PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY
     SERVICING, REPAIR OR CORRECTION.

 13. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
     WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY
     MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE
     LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL,
     INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR
     INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
     DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU
     OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY
     OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN
     ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

                      END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
=============================================

If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.

   To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

     ONE LINE TO GIVE THE PROGRAM'S NAME AND AN IDEA OF WHAT IT DOES.
     Copyright (C) 19YY  NAME OF AUTHOR

     This program is free software; you can redistribute it and/or
     modify it under the terms of the GNU General Public License
     as published by the Free Software Foundation; either version 2
     of the License, or (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License along
     with this program; if not, write to the Free Software Foundation, Inc.,
     59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

   Also add information on how to contact you by electronic and paper
mail.

   If the program is interactive, make it output a short notice like
this when it starts in an interactive mode:

     Gnomovision version 69, Copyright (C) 19YY NAME OF AUTHOR
     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
     type `show w'.  This is free software, and you are welcome
     to redistribute it under certain conditions; type `show c'
     for details.

   The hypothetical commands `show w' and `show c' should show the
appropriate parts of the General Public License.  Of course, the
commands you use may be called something other than `show w' and `show
c'; they could even be mouse-clicks or menu items--whatever suits your
program.

   You should also get your employer (if you work as a programmer) or
your school, if any, to sign a "copyright disclaimer" for the program,
if necessary.  Here is a sample; alter the names:

     Yoyodyne, Inc., hereby disclaims all copyright
     interest in the program `Gnomovision'
     (which makes passes at compilers) written
     by James Hacker.

     SIGNATURE OF TY COON, 1 April 1989
     Ty Coon, President of Vice

   This General Public License does not permit incorporating your
program into proprietary programs.  If your program is a subroutine
library, you may consider it more useful to permit linking proprietary
applications with the library.  If this is what you want to do, use the
GNU Library General Public License instead of this License.


File: mach.info,  Node: Documentation License,  Next: Concept Index,  Prev: Copying,  Up: Top

Appendix B Documentation License
********************************

This manual is copyrighted and licensed under the GNU Free Documentation
license.

   Parts of this manual are derived from the Mach manual packages
originally provided by Carnegie Mellon University.

* Menu:

* Free Documentation License::    The GNU Free Documentation License.
* CMU License::                   The CMU license applies to the original Mach
                                  kernel and its documentation.


File: mach.info,  Node: Free Documentation License,  Next: CMU License,  Up: Documentation License

B.1 GNU Free Documentation License
==================================

                        Version 1.1, March 2000

     Copyright (C) 2000 Free Software Foundation, Inc.
     59 Temple Place, Suite 330, Boston, MA  02111-1307, USA

     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.

  0. PREAMBLE

     The purpose of this License is to make a manual, textbook, or other
     written document "free" in the sense of freedom: to assure everyone
     the effective freedom to copy and redistribute it, with or without
     modifying it, either commercially or noncommercially.  Secondarily,
     this License preserves for the author and publisher a way to get
     credit for their work, while not being considered responsible for
     modifications made by others.

     This License is a kind of "copyleft", which means that derivative
     works of the document must themselves be free in the same sense.
     It complements the GNU General Public License, which is a copyleft
     license designed for free software.

     We have designed this License in order to use it for manuals for
     free software, because free software needs free documentation: a
     free program should come with manuals providing the same freedoms
     that the software does.  But this License is not limited to
     software manuals; it can be used for any textual work, regardless
     of subject matter or whether it is published as a printed book.
     We recommend this License principally for works whose purpose is
     instruction or reference.

  1. APPLICABILITY AND DEFINITIONS

     This License applies to any manual or other work that contains a
     notice placed by the copyright holder saying it can be distributed
     under the terms of this License.  The "Document", below, refers to
     any such manual or work.  Any member of the public is a licensee,
     and is addressed as "you".

     A "Modified Version" of the Document means any work containing the
     Document or a portion of it, either copied verbatim, or with
     modifications and/or translated into another language.

     A "Secondary Section" is a named appendix or a front-matter
     section of the Document that deals exclusively with the
     relationship of the publishers or authors of the Document to the
     Document's overall subject (or to related matters) and contains
     nothing that could fall directly within that overall subject.
     (For example, if the Document is in part a textbook of
     mathematics, a Secondary Section may not explain any mathematics.)
     The relationship could be a matter of historical connection with
     the subject or with related matters, or of legal, commercial,
     philosophical, ethical or political position regarding them.

     The "Invariant Sections" are certain Secondary Sections whose
     titles are designated, as being those of Invariant Sections, in
     the notice that says that the Document is released under this
     License.

     The "Cover Texts" are certain short passages of text that are
     listed, as Front-Cover Texts or Back-Cover Texts, in the notice
     that says that the Document is released under this License.

     A "Transparent" copy of the Document means a machine-readable copy,
     represented in a format whose specification is available to the
     general public, whose contents can be viewed and edited directly
     and straightforwardly with generic text editors or (for images
     composed of pixels) generic paint programs or (for drawings) some
     widely available drawing editor, and that is suitable for input to
     text formatters or for automatic translation to a variety of
     formats suitable for input to text formatters.  A copy made in an
     otherwise Transparent file format whose markup has been designed
     to thwart or discourage subsequent modification by readers is not
     Transparent.  A copy that is not "Transparent" is called "Opaque".

     Examples of suitable formats for Transparent copies include plain
     ASCII without markup, Texinfo input format, LaTeX input format,
     SGML or XML using a publicly available DTD, and
     standard-conforming simple HTML designed for human modification.
     Opaque formats include PostScript, PDF, proprietary formats that
     can be read and edited only by proprietary word processors, SGML
     or XML for which the DTD and/or processing tools are not generally
     available, and the machine-generated HTML produced by some word
     processors for output purposes only.

     The "Title Page" means, for a printed book, the title page itself,
     plus such following pages as are needed to hold, legibly, the
     material this License requires to appear in the title page.  For
     works in formats which do not have any title page as such, "Title
     Page" means the text near the most prominent appearance of the
     work's title, preceding the beginning of the body of the text.

  2. VERBATIM COPYING

     You may copy and distribute the Document in any medium, either
     commercially or noncommercially, provided that this License, the
     copyright notices, and the license notice saying this License
     applies to the Document are reproduced in all copies, and that you
     add no other conditions whatsoever to those of this License.  You
     may not use technical measures to obstruct or control the reading
     or further copying of the copies you make or distribute.  However,
     you may accept compensation in exchange for copies.  If you
     distribute a large enough number of copies you must also follow
     the conditions in section 3.

     You may also lend copies, under the same conditions stated above,
     and you may publicly display copies.

  3. COPYING IN QUANTITY

     If you publish printed copies of the Document numbering more than
     100, and the Document's license notice requires Cover Texts, you
     must enclose the copies in covers that carry, clearly and legibly,
     all these Cover Texts: Front-Cover Texts on the front cover, and
     Back-Cover Texts on the back cover.  Both covers must also clearly
     and legibly identify you as the publisher of these copies.  The
     front cover must present the full title with all words of the
     title equally prominent and visible.  You may add other material
     on the covers in addition.  Copying with changes limited to the
     covers, as long as they preserve the title of the Document and
     satisfy these conditions, can be treated as verbatim copying in
     other respects.

     If the required texts for either cover are too voluminous to fit
     legibly, you should put the first ones listed (as many as fit
     reasonably) on the actual cover, and continue the rest onto
     adjacent pages.

     If you publish or distribute Opaque copies of the Document
     numbering more than 100, you must either include a
     machine-readable Transparent copy along with each Opaque copy, or
     state in or with each Opaque copy a publicly-accessible
     computer-network location containing a complete Transparent copy
     of the Document, free of added material, which the general
     network-using public has access to download anonymously at no
     charge using public-standard network protocols.  If you use the
     latter option, you must take reasonably prudent steps, when you
     begin distribution of Opaque copies in quantity, to ensure that
     this Transparent copy will remain thus accessible at the stated
     location until at least one year after the last time you
     distribute an Opaque copy (directly or through your agents or
     retailers) of that edition to the public.

     It is requested, but not required, that you contact the authors of
     the Document well before redistributing any large number of
     copies, to give them a chance to provide you with an updated
     version of the Document.

  4. MODIFICATIONS

     You may copy and distribute a Modified Version of the Document
     under the conditions of sections 2 and 3 above, provided that you
     release the Modified Version under precisely this License, with
     the Modified Version filling the role of the Document, thus
     licensing distribution and modification of the Modified Version to
     whoever possesses a copy of it.  In addition, you must do these
     things in the Modified Version:

       A. Use in the Title Page (and on the covers, if any) a title
          distinct from that of the Document, and from those of
          previous versions (which should, if there were any, be listed
          in the History section of the Document).  You may use the
          same title as a previous version if the original publisher of
          that version gives permission.

       B. List on the Title Page, as authors, one or more persons or
          entities responsible for authorship of the modifications in
          the Modified Version, together with at least five of the
          principal authors of the Document (all of its principal
          authors, if it has less than five).

       C. State on the Title page the name of the publisher of the
          Modified Version, as the publisher.

       D. Preserve all the copyright notices of the Document.

       E. Add an appropriate copyright notice for your modifications
          adjacent to the other copyright notices.

       F. Include, immediately after the copyright notices, a license
          notice giving the public permission to use the Modified
          Version under the terms of this License, in the form shown in
          the Addendum below.

       G. Preserve in that license notice the full lists of Invariant
          Sections and required Cover Texts given in the Document's
          license notice.

       H. Include an unaltered copy of this License.

       I. Preserve the section entitled "History", and its title, and
          add to it an item stating at least the title, year, new
          authors, and publisher of the Modified Version as given on
          the Title Page.  If there is no section entitled "History" in
          the Document, create one stating the title, year, authors,
          and publisher of the Document as given on its Title Page,
          then add an item describing the Modified Version as stated in
          the previous sentence.

       J. Preserve the network location, if any, given in the Document
          for public access to a Transparent copy of the Document, and
          likewise the network locations given in the Document for
          previous versions it was based on.  These may be placed in
          the "History" section.  You may omit a network location for a
          work that was published at least four years before the
          Document itself, or if the original publisher of the version
          it refers to gives permission.

       K. In any section entitled "Acknowledgments" or "Dedications",
          preserve the section's title, and preserve in the section all
          the substance and tone of each of the contributor
          acknowledgments and/or dedications given therein.

       L. Preserve all the Invariant Sections of the Document,
          unaltered in their text and in their titles.  Section numbers
          or the equivalent are not considered part of the section
          titles.

       M. Delete any section entitled "Endorsements".  Such a section
          may not be included in the Modified Version.

       N. Do not retitle any existing section as "Endorsements" or to
          conflict in title with any Invariant Section.

     If the Modified Version includes new front-matter sections or
     appendices that qualify as Secondary Sections and contain no
     material copied from the Document, you may at your option
     designate some or all of these sections as invariant.  To do this,
     add their titles to the list of Invariant Sections in the Modified
     Version's license notice.  These titles must be distinct from any
     other section titles.

     You may add a section entitled "Endorsements", provided it contains
     nothing but endorsements of your Modified Version by various
     parties--for example, statements of peer review or that the text
     has been approved by an organization as the authoritative
     definition of a standard.

     You may add a passage of up to five words as a Front-Cover Text,
     and a passage of up to 25 words as a Back-Cover Text, to the end
     of the list of Cover Texts in the Modified Version.  Only one
     passage of Front-Cover Text and one of Back-Cover Text may be
     added by (or through arrangements made by) any one entity.  If the
     Document already includes a cover text for the same cover,
     previously added by you or by arrangement made by the same entity
     you are acting on behalf of, you may not add another; but you may
     replace the old one, on explicit permission from the previous
     publisher that added the old one.

     The author(s) and publisher(s) of the Document do not by this
     License give permission to use their names for publicity for or to
     assert or imply endorsement of any Modified Version.

  5. COMBINING DOCUMENTS

     You may combine the Document with other documents released under
     this License, under the terms defined in section 4 above for
     modified versions, provided that you include in the combination
     all of the Invariant Sections of all of the original documents,
     unmodified, and list them all as Invariant Sections of your
     combined work in its license notice.

     The combined work need only contain one copy of this License, and
     multiple identical Invariant Sections may be replaced with a single
     copy.  If there are multiple Invariant Sections with the same name
     but different contents, make the title of each such section unique
     by adding at the end of it, in parentheses, the name of the
     original author or publisher of that section if known, or else a
     unique number.  Make the same adjustment to the section titles in
     the list of Invariant Sections in the license notice of the
     combined work.

     In the combination, you must combine any sections entitled
     "History" in the various original documents, forming one section
     entitled "History"; likewise combine any sections entitled
     "Acknowledgments", and any sections entitled "Dedications".  You
     must delete all sections entitled "Endorsements."

  6. COLLECTIONS OF DOCUMENTS

     You may make a collection consisting of the Document and other
     documents released under this License, and replace the individual
     copies of this License in the various documents with a single copy
     that is included in the collection, provided that you follow the
     rules of this License for verbatim copying of each of the
     documents in all other respects.

     You may extract a single document from such a collection, and
     distribute it individually under this License, provided you insert
     a copy of this License into the extracted document, and follow
     this License in all other respects regarding verbatim copying of
     that document.

  7. AGGREGATION WITH INDEPENDENT WORKS

     A compilation of the Document or its derivatives with other
     separate and independent documents or works, in or on a volume of
     a storage or distribution medium, does not as a whole count as a
     Modified Version of the Document, provided no compilation
     copyright is claimed for the compilation.  Such a compilation is
     called an "aggregate", and this License does not apply to the
     other self-contained works thus compiled with the Document, on
     account of their being thus compiled, if they are not themselves
     derivative works of the Document.

     If the Cover Text requirement of section 3 is applicable to these
     copies of the Document, then if the Document is less than one
     quarter of the entire aggregate, the Document's Cover Texts may be
     placed on covers that surround only the Document within the
     aggregate.  Otherwise they must appear on covers around the whole
     aggregate.

  8. TRANSLATION

     Translation is considered a kind of modification, so you may
     distribute translations of the Document under the terms of section
     4.  Replacing Invariant Sections with translations requires special
     permission from their copyright holders, but you may include
     translations of some or all Invariant Sections in addition to the
     original versions of these Invariant Sections.  You may include a
     translation of this License provided that you also include the
     original English version of this License.  In case of a
     disagreement between the translation and the original English
     version of this License, the original English version will prevail.

  9. TERMINATION

     You may not copy, modify, sublicense, or distribute the Document
     except as expressly provided for under this License.  Any other
     attempt to copy, modify, sublicense or distribute the Document is
     void, and will automatically terminate your rights under this
     License.  However, parties who have received copies, or rights,
     from you under this License will not have their licenses
     terminated so long as such parties remain in full compliance.

 10. FUTURE REVISIONS OF THIS LICENSE

     The Free Software Foundation may publish new, revised versions of
     the GNU Free Documentation License from time to time.  Such new
     versions will be similar in spirit to the present version, but may
     differ in detail to address new problems or concerns.  See
     `http://www.gnu.org/copyleft/'.

     Each version of the License is given a distinguishing version
     number.  If the Document specifies that a particular numbered
     version of this License "or any later version" applies to it, you
     have the option of following the terms and conditions either of
     that specified version or of any later version that has been
     published (not as a draft) by the Free Software Foundation.  If
     the Document does not specify a version number of this License,
     you may choose any version ever published (not as a draft) by the
     Free Software Foundation.

B.1.0.1 ADDENDUM: How to use this License for your documents
............................................................

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:

       Copyright (C)  YEAR  YOUR NAME.
       Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version 1.1
       or any later version published by the Free Software Foundation;
       with the Invariant Sections being LIST THEIR TITLES, with the
       Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
       A copy of the license is included in the section entitled ``GNU
       Free Documentation License''.

   If you have no Invariant Sections, write "with no Invariant Sections"
instead of saying which ones are invariant.  If you have no Front-Cover
Texts, write "no Front-Cover Texts" instead of "Front-Cover Texts being
LIST"; likewise for Back-Cover Texts.

   If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License, to
permit their use in free software.


File: mach.info,  Node: CMU License,  Prev: Free Documentation License,  Up: Documentation License

B.2 CMU License
===============

          Mach Operating System
          Copyright (C) 1991,1990,1989 Carnegie Mellon University
          All Rights Reserved.

     Permission to use, copy, modify and distribute this software and
     its documentation is hereby granted, provided that both the
     copyright notice and this permission notice appear in all copies
     of the software, derivative works or modified versions, and any
     portions thereof, and that both notices appear in supporting
     documentation.

     CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.

     Carnegie Mellon requests users of this software to return to

           Software Distribution Coordinator
           School of Computer Science
           Carnegie Mellon University
           Pittsburgh PA 15213-3890

     or <Software.Distribution@CS.CMU.EDU> any improvements or
     extensions that they make and grant Carnegie Mellon the rights to
     redistribute these changes.


File: mach.info,  Node: Concept Index,  Next: Function and Data Index,  Prev: Documentation License,  Up: Top

Concept Index
*************