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unix系统下top命令的源代码

                             TOP
                         Version 3.5

                       William LeFebvre
		     and a cast of dozens


If you do not want to read this entire file, then at least read
the section at the end entitled "KNOWN PROBLEMS".

If you are having any problems getting top to work, please read the
file "FAQ" *before* contacting me.  Thank you.

"top" is a program that will give continual reports about the state of
the system, including a list of the top cpu using processes.  Version 3
of "top" has three primary design goals: provide an accurate snapshot of
the system and process state, not be one of the top processes itself, be
as portable as possible.

Version 3 has many bug fixes from version 2.5, and it has also been
reorganized in a major way to make it easy to port to other platforms.
All system dependent code is now contained in one file.

Top now includes a configuration script called "Configure".  It helps
the installer choose the correct parameters for this particular
installation.  This script MUST be run before attempting to compile top.

Top requires read access to the memory files "/dev/kmem" and "/dev/mem"
as well as the system image "/vmunix".  Some installations have these
files protected from general access.  These sites would have to install
this program in the same way that programs such as "ps" are installed.
In addition, on those Unix variants that support the proc filesystem
(such as SVR4 and Solaris 2), top requires read access to all the files
in /proc: typically dictating that top be installed setuid to root.

CAVEAT: version 3 of top has internal commands that kill and renice
processes.  Although I have taken steps to insure that top makes
appropriate checks with these commands, I cannot guarantee that these
internal commands are totally secure.  IF YOU INSTALL top as a SETUID
program, you do so AT YOUR OWN RISK!  I realize that some operating
systems will require top to run setuid, and I will do everything I can
to make sure that top is a secure setuid program.

Configure will ask you to input values for certain parameters.  Before
each parameter, Configure will display a description of what the
parameter does.  Read the description and choose an appropriate value.
Sometimes a default will appear in brackets.  Typing just return will
choose the default.

System support now takes the form of "modules".  Adding support for
a different architecture requires only adding a module.  Configure
asks which module to use when it is configuring top.  See the file
"Porting" for a description of how to write your own module.

To compile and install "top", read the file "INSTALL" and follow the
directions and advice contained therein.

Once you have created a binary for one particular type of machine, you
can reconfigure for another type with "./Configure modulename" where
"modulename" is replaced with the appropriate module name.  All other
parameter values are kept the same.  Note that in some cases this may
not be appropriate.

If you make any kind of change to "top" that you feel would be
beneficial to others who use this program, or if you find and fix a bug,
please send me the change.

Be sure to read the FAQ enclosed with the distrubution.  It contains
answers to the most commonly asked questions about the configuration,
installation, and operation of top.


AVAILABILITY

The latest version of "top" is now being made available via anonymous
FTP from the host "ftp.groupsys.com" in the directory "/pub/top".
Additional modules will be made available in the directory
"/pub/top/m".  The site "eecs.nwu.edu" will continue to house copies
of the distribution as well.

Here are HTML links for the four best "top" archive sites:

<A HREF="ftp://ftp.groupsys.com/pub/top">Top archive (groupsys.com)</A>
<A HREF="ftp://eecs.nwu.edu/pub/top">Top archive (eecs.nwu.edu)</A>
<A HREF="ftp://pharos.dgim.doc.ca/packages/top"> Top mirror (dgim.doc.ca)</A>
<A HREF="ftp://uiarchive.uiuc.edu/pub/packages/top/">Top mirror (uiuc.edu)</A>

New releases will be posted to comp.sources.unix as they become
available.  Sites which arhive that newsgroup will also contain copies
of the distribution.

Announcements about availability will be made to the mailing list
"[e-mail]".  This is an open list maintained by
majordomo.  To join the list, send a message containing the word
"subscribe" to "[e-mail]".  Addresses of
subscribers to this list are kept confidential and will never be used
for any purpose other than as recipients of announements concerning
this software.


KNOWN PROBLEMS:

Gnu CC

Compiling via Gnu CC continued to be the source of most of the
questions I receive.  By far the most common mistake made by those
attempting to compile top with Gnu CC is out of date include files.
When the operating system is upgraded, the include files that are part
of the gcc package MUST also be updated.  Gcc maintains its own
include files.  Even a minor OS upgrade can involve changes to some of
the kernel's internal data structures, which are defined in include
files in "sys".  Top is very sensitive to these changes.  If you are
compiling with gcc and experience any sort of strange problems, please
make sure the include files you are using are up to date BEFORE
sending me a bug report.  Look in the gcc source distribution for the
shell script "fixincludes".

HP/UX 10.10

In their infinite wisdom, the folks at HP have decided that mere mortals
such as you and I don't need to know what the kernel's proc structure looks
like.  To that end, they have removed all useful content from the include
file <sys/proc.h> in version 10.10.  As a result, top will not compile
under 10.10.  What HP is trying to accomplish with this move is to force
iconoclasts such as myself to use "pstat" for collecting all process
information.  I have no immediate solution for this problem, but hope to
obtain a sufficiently complete definition of "struct proc" at some point in
the near future.  Stay tuned.

DIGITAL UNIX 4.0 (DECOSF/1 V4.0)

A user has reported that idle processes are not displayed regardless
of the flags used when invoking top.  We have not had time to track
this problem down.

DECOSF/1 V3.0

There is a bug either in the module, in utils.c, or in DEC's optimizer that
is tickled by the decosf1 module when compiled under V3.0 (and perhaps
earlier versions).  Top compiled using DEC's compiler with optimization
will consistently produce a segmentation fault (in format_next_process
while calling sprintf).  To work around this problem, either compile top
with gcc or turn off optimization (compile without -O).  We think that
one of the bugs fixed in utils.c fixed this problem as well, but we are
not certain.


System V R 4.2

Load average and memory displays do not work.  The problem has been
traced down to a potential bug in the "mem" driver.  The author
of the svr42 module is working on a fix.



GRATITUDE

My perpetual thanks to all the people who have helped me support top
on so many platforms.  Without these people, top would not be what it
is.  Here is a partial list of contributors and other individuals.

	Robert Boucher		<[e-mail]>
	Marc Cohen 		<[e-mail]>
	David Cutter		<[e-mail]>
	Casper Dik		<[e-mail]>
	Charles Hedrick 	<[e-mail]>
	Andrew Herbert		<[e-mail]>
	Jeff Janvrin		<[e-mail]>
	Torsten Kasch 		<[e-mail]>
	Petri Kutvonen		<[e-mail]>
	William L. Jones 	<jones@chpc>
	Tim Pugh 		<[e-mail]>
	Steve Scherf		<[e-mail]>
	Phillip Wu		<[e-mail]>

(My apologies if I missed anyone.)


AUTHOR

		William LeFebvre
		Group sys Consulting
		[e-mail]


		U.S. Mail address:
		    William LeFebvre
		    Group sys Consulting
		    11585 Jones Bridge Road
		    Suite 420-139
		    Alpharetta, GA  30022
		    [phone]