57 lines
3.0 KiB
Perl
57 lines
3.0 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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.\" @(#)1.0.t 8.1 (Berkeley) 6/8/93
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.\"
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.ds ss 1
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.sh "Kernel primitives
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.PP
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The facilities available to a UNIX user process are logically
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divided into two parts: kernel facilities directly implemented by
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UNIX code running in the operating system, and system facilities
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implemented either by the system, or in cooperation with a
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\fIserver process\fP. These kernel facilities are described in
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this section 1.
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.PP
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The facilities implemented in the kernel are those which define the
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\fIUNIX virtual machine\fP in which each process runs.
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Like many real machines, this virtual machine has memory management hardware,
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an interrupt facility, timers and counters. The UNIX
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virtual machine also allows access to files and other objects through a set of
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\fIdescriptors\fP. Each descriptor resembles a device controller,
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and supports a set of operations. Like devices on real machines, some
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of which are internal to the machine and some of which are external,
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parts of the descriptor machinery are built-in to the operating system, while
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other parts are often implemented in server processes on other machines.
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The facilities provided through the descriptor machinery are described in
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section 2.
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.ds ss 2
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