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189 lines
7.7 KiB
Perl
189 lines
7.7 KiB
Perl
.\" Copyright (c) 1983, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)2.t 8.1 (Berkeley) 6/8/93
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.\"
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.\".ds RH "Configuration File Contents
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.ne 2i
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.NH
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CONFIGURATION FILE CONTENTS
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.PP
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A system configuration must include at least the following
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pieces of information:
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.IP \(bu 3
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machine type
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.IP \(bu 3
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cpu type
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.IP \(bu 3
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system identification
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.IP \(bu 3
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timezone
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.IP \(bu 3
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maximum number of users
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.IP \(bu 3
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location of the root file system
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.IP \(bu 3
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available hardware
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.PP
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.I Config
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allows multiple system images to be generated from a single
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configuration description. Each system image is configured
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for identical hardware, but may have different locations for the root
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file system and, possibly, other system devices.
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.NH 2
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Machine type
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.PP
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The
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.I "machine type"
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indicates if the system is going to operate on a DEC VAX-11\(dg computer,
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.FS
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\(dg DEC, VAX, UNIBUS, MASSBUS and MicroVAX are trademarks of Digital
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Equipment Corporation.
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.FE
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or some other machine on which 4.4BSD operates. The machine type
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is used to locate certain data files which are machine specific, and
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also to select rules used in constructing the resultant
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configuration files.
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.NH 2
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Cpu type
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.PP
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The
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.I "cpu type"
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indicates which, of possibly many, cpu's the system is to operate on.
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For example, if the system is being configured for a VAX-11, it could
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be running on a VAX 8600, VAX-11/780, VAX-11/750, VAX-11/730 or MicroVAX II.
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(Other VAX cpu types, including the 8650, 785 and 725, are configured using
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the cpu designation for compatible machines introduced earlier.)
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Specifying
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more than one cpu type implies that the system should be configured to run
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on any of the cpu's specified. For some types of machines this is not
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possible and
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.I config
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will print a diagnostic indicating such.
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.NH 2
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System identification
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.PP
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The
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.I "system identification"
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is a moniker attached to the system, and often the machine on which the
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system is to run. For example, at Berkeley we have machines named Ernie
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(Co-VAX), Kim (No-VAX), and so on. The system identifier selected is used to
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create a global C ``#define'' which may be used to isolate system dependent
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pieces of code in the kernel. For example, Ernie's Varian driver used
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to be special cased because its interrupt vectors were wired together. The
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code in the driver which understood how to handle this non-standard hardware
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configuration was conditionally compiled in only if the system
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was for Ernie.
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.PP
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The system identifier ``GENERIC'' is given to a system which
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will run on any cpu of a particular machine type; it should not
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otherwise be used for a system identifier.
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.NH 2
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Timezone
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.PP
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The timezone in which the system is to run is used to define the
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information returned by the \fIgettimeofday\fP\|(2)
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system call. This value is specified as the number of hours east
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or west of GMT. Negative numbers indicate a value east of GMT.
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The timezone specification may also indicate the
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type of daylight savings time rules to be applied.
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.NH 2
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Maximum number of users
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.PP
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The system allocates many system data structures at boot time
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based on the maximum number of users the system will support.
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This number is normally between 8 and 40, depending
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on the hardware and expected job mix. The rules
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used to calculate system data structures are discussed in
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Appendix D.
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.NH 2
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Root file system location
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.PP
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When the system boots it must know the location of
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the root of the file system
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tree. This location and the part(s) of the disk(s) to be used
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for paging and swapping must be specified in order to create
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a complete configuration description.
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.I Config
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uses many rules to calculate default locations for these items;
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these are described in Appendix B.
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.PP
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When a generic system is configured, the root file system is left
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undefined until the system is booted. In this case, the root file
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system need not be specified, only that the system is a generic system.
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.NH 2
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Hardware devices
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.PP
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When the system boots it goes through an
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.I autoconfiguration
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phase. During this period, the system searches for all
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those hardware devices
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which the system builder has indicated might be present. This probing
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sequence requires certain pieces of information such as register
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addresses, bus interconnects, etc. A system's hardware may be configured
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in a very flexible manner or be specified without any flexibility
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whatsoever. Most people do not configure hardware devices into the
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system unless they are currently present on the machine, expect
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them to be present in the near future, or are simply guarding
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against a hardware
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failure somewhere else at the site (it is often wise to configure in
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extra disks in case an emergency requires moving one off a machine which
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has hardware problems).
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.PP
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The specification of hardware devices usually occupies the majority of
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the configuration file. As such, a large portion of this document will
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be spent understanding it. Section 6.3 contains a description of
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the autoconfiguration process, as it applies to those planning to
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write, or modify existing, device drivers.
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.NH 2
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Pseudo devices
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.PP
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Several system facilities are configured in a manner like that used
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for hardware devices although they are not associated with specific hardware.
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These system options are configured as
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.IR pseudo-devices .
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Some pseudo devices allow an optional parameter that sets the limit
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on the number of instances of the device that are active simultaneously.
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.NH 2
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System options
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.PP
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Other than the mandatory pieces of information described above, it
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is also possible to include various optional system facilities
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or to modify system behavior and/or limits.
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For example, 4.4BSD can be configured to support binary compatibility for
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programs built under 4.3BSD. Also, optional support is provided
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for disk quotas and tracing the performance of the virtual memory
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subsystem. Any optional facilities to be configured into
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the system are specified in the configuration file. The resultant
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files generated by
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.I config
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will automatically include the necessary pieces of the system.
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