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CONFIG(8)		FreeBSD	System Manager's Manual		     CONFIG(8)

NAME
     config -- build system configuration files

SYNOPSIS
     config [-gpr] [-d destdir]	SYSTEM_NAME

DESCRIPTION
     This is the old version of	the config program.  It	understands the	old
     autoconfiguration scheme used on the HP300, i386, DECstation, and deriva-
     tive platforms.  The new version of config	is used	with the SPARC plat-
     form.  Only the version of	config applicable to the architecture that you
     are running will be installed on your machine.

     config builds a set of system configuration files from the	file
     SYSTEM_NAME which describes the system to configure.  A second file tells
     config what files are needed to generate a	system and can be augmented by
     configuration specific set	of files that give alternate files for a spe-
     cific machine (see	the FILES section below).

     Available options and operands:

     -d	destdir	  Use destdir as the output directory, instead of the default
		  one.	Note that config does not append SYSTEM_NAME to	the
		  directory given.

     -g		  Configure a system for debugging.

     -p		  Configure a system for profiling; for	example, kgmon(8) and
		  gprof(1).  If	two or more -p options are supplied, config
		  configures a system for high resolution profiling.

     -r		  Remove the old compile directory (see	below).

     SYSTEM_NAME  Specify the name of the system configuration file containing
		  device specifications, configuration options and other sys-
		  tem parameters for one system	configuration.

     config should be run from the conf	subdirectory of	the system source
     (usually /sys/ARCH/conf), where ARCH represents one of the	architectures
     supported by FreeBSD.  config creates the directory
     ../../compile/SYSTEM_NAME or the one given	with the -d option as neces-
     sary and places all output	files there.  If the output directory already
     exists and	the -r flag was	specified, it will be removed first.  The out-
     put of config consists of a number	of files; for the i386,	they are:
     ioconf.c, a description of	what I/O devices are attached to the system;
     Makefile, used by make(1) in building the system; header files, defini-
     tions of the number of various devices that will be compiled into the
     system.

     After running config, it is necessary to run ``make depend'' in the
     directory where the new makefile was created.  config prints a reminder
     of	this when it completes.

     If	any other error	messages are produced by config, the problems in the
     configuration file	should be corrected and	config should be run again.
     Attempts to compile a system that had configuration errors	are likely to
     fail.

     If	the options INCLUDE_CONFIG_FILE	is used	in the configuration file the
     entire input file is embedded in the new kernel.  This means that
     strings(1)	can be used to extract it from a kernel: to extract the	con-
     figuration	information, use the command

	   strings kernel | grep ___

DEBUG KERNELS
     Traditional BSD kernels compiled without symbols due to the heavy load on
     the system	when compiling a ``debug'' kernel.  A debug kernel contains
     complete symbols for all the source files,	and enables an experienced
     kernel programmer to analyse the cause of a problem.  The debuggers
     available prior to	4.4BSD-Lite were able to find some information from a
     normal kernel; gdb(1) provides very little	support	for normal kernels,
     and a debug kernel	is needed for any meaningful analysis.

     For reasons of history, time and space, building a	debug kernel is	not
     the default with FreeBSD: a debug kernel takes up to 30% longer to	build
     and requires about	30 MB of disk storage in the build directory, compared
     to	about 6	MB for a non-debug kernel.  A debug kernel is about 11 MB in
     size, compared to about 2 MB for a	non-debug kernel.  This	space is used
     both in the root file system and at run time in memory.  Use the -g
     option to build a debug kernel.  With this	option,	config causes two ker-
     nel files to be built in the kernel build directory:

     +o	 kernel.debug is the complete debug kernel.

     +o	 kernel	is a copy of the kernel	with the debug symbols stripped	off.
	 This is equivalent to the normal non-debug kernel.

     There is currently	little sense in	installing and booting from a debug
     kernel, since the only tools available which use the symbols do not run
     on-line.  There are therefore two options for installing a	debug kernel:

     +o	 ``make	install'' installs kernel in the root file system.

     +o	 ``make	install.debug''	installs kernel.debug in the root file system.

FILES
     /sys/conf/files		       list of common files system is built
				       from
     /sys/conf/Makefile.ARCH	       generic makefile	for the	ARCH
     /sys/conf/files.ARCH	       list of ARCH specific files
     /sys/ARCH/conf/files.SYSTEM_NAME  list of files specific to SYSTEM_NAME
				       on ARCH
     /sys/compile/SYSTEM_NAME	       default kernel build directory for sys-
				       tem SYSTEM_NAME.

SEE ALSO
     The SYNOPSIS portion of each device in section 4.

     Building 4.3 BSD UNIX System with Config.

BUGS
     The line numbers reported in error	messages are usually off by one.

HISTORY
     The config	command	appeared in 4.1BSD.

FreeBSD	10.1			 July 4, 2001			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | DEBUG KERNELS | FILES | SEE ALSO | BUGS | HISTORY

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