docs/70674: [PATCH] Update handbook to match 5.3R (8.4 - The Configuration File)

Wed Aug 25 08:10:42 UTC 2004

The following reply was made to PR docs/70674; it has been noted by GNATS.

From: Peter Pentchev <roam at ringlet.net>
To: Joel Dahl <joel at automatvapen.se>
Cc: bug-followup at FreeBSD.org
Subject: Re: docs/70674: [PATCH] Update handbook to match 5.3R (8.4 - The Configuration File)
Date: Wed, 25 Aug 2004 11:05:12 +0300

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 On Fri, Aug 20, 2004 at 04:50:32PM +0000, Joel Dahl wrote:
 >  --- chapter.sgml	Thu Aug 19 16:05:42 2004
 >  +++ new.chapter.sgml	Thu Aug 19 21:16:12 2004

 Great going!  A rewrite (or at least a retouch) of the kernel config
 section is indeed needed, thanks for taking the time to do it!
 But... :) see below for a couple of comments.

 >  @@ -426,19 +426,18 @@
 >         some related keywords have been grouped together in a single sect=
 ion
 >         (such as Networking) even though they are actually scattered
 >         throughout the <filename>GENERIC</filename> file.  <anchor
 [snip]
 >  +      id=3D"kernelconfig-options"> An exhaustive list of architecure
 >  +      dependent options and more detailed explanations of the device li=
 nes
 >  +      is present in the <filename>NOTES</filename> configuration file,
 >  +      located in the same directory as <filename>GENERIC</filename>. If=
  you
 >  +      are in doubt as to the purpose or necessity of a line, check firs=
 t in
 >  +      <filename>NOTES</filename>. Architecure independent options are
 >  +      stored in <filename>/usr/src/sys/conf/NOTES</filename>.</para>
 >  +
 >  +    <note><para>In &os; 4.X and earlier <filename>NOTES</filename> is
 >  +      non-existent. Instead, see the <filename>LINT</filename> file for
 >  +      detailed explanations of options in <filename>GENERIC</filename>.
 >  +      </para></note>

 Actually, just substituting NOTES for LINT is not quite (or at least not
 completely) correct.  It is true that the sys/conf/NOTES and
 sys/<arch>/conf/NOTES files are the place one should look when choosing
 kernel options to include (or remove) when building a custom kernel
 config, so that much is correct.  However, there is a bit more to be
 said about the NOTES vs LINT issue, and it might need a little detour
 into history :)

 The purpose of the LINT kernel config in FreeBSD 4.x and earlier was
 actually twofold: to provide a reference for choosing kernel options
 when building a custom kernel, *and* to provide a kernel configuration
 file with as much drivers/options included as possible and as many
 tweakable knobs tweaked to non-default values as possible.  The idea was
 that such a kernel config should (and does) help a lot in checking
 whether new code or changes to existing code will cause conflicts with
 other parts of the kernel.

 Then, about 4 years ago, Peter Wemm borrowed Poul-Henning Kamp's axe and
 took it to the kernel configuration framework, almost turning the thing
 inside out :)  The part of this change that interests us most is the
 fact that the driver configuration options that were so far stored in
 the kernel config (e.g. 'device ppc0 at isa? irq 7') were moved to a
 so-called 'hints' file, so that they could be changed and loaded
 dynamically at boot time.  Among other things, this meant that the LINT
 file could no longer contain those hints (since the syntax had changed
 to just 'device ppc' and a separate line *in a separate file*), so for
 this and other reasons, the file-formerly-known-as-LINT was renamed to
 (nope, not 'Symbol') NOTES and retained mostly the first reason for its
 existence: documenting the available options for user convenience.
 However, the second reason - building a kernel with all the bells and
 whistles and seeing which of those do not play nice with each other -
 was (and is) still very, very important, so in the same change 4 years
 ago Peter Wemm also created sys/<arch>/conf/Makefile with the sole
 purpose of taking sys/<arch>/conf/NOTES and sys/conf/NOTES and
 converting them into a buildable kernel config file named - yep, you
 guessed it - LINT.

 So basically, it's not so much that NOTES doesn't exist in 4.x, it's
 more like LINT turned to NOTES in 5.x, but you can still generate a
 buildable LINT:

   # cd /sys/i386/conf && make LINT

 =2E..and you can later build the LINT kernel:

   # cd /usr/src && make KERNCONF=3DLINT NO_MODULES=3Dyes buildkernel

 (the NO_MODULES part serves two purposes: first, pretty much all the
 code is *in* the LINT kernel, and second, nobody in their right mind
 would actually try to *boot* the thing :)

 Soooo... do you think you could somehow integrate some of those mindless
 ravings of mine (rewording where necessary :) into your changes?  And
 it's okay if you don't want to - sometimes I amaze myself when I look at
 things I've written a couple of months ago and wonder just how could I
 have been so dumb and/or unclear :)

 G'luck,
 Peter

 --=20
 Peter Pentchev	roam at ringlet.net    roam at cnsys.bg    roam at FreeBSD.org
 PGP key:	http://people.FreeBSD.org/~roam/roam.key.asc
 Key fingerprint	FDBA FD79 C26F 3C51 C95E  DF9E ED18 B68D 1619 4553
 If this sentence didn't exist, somebody would have invented it.

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