1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software written and contributed 5.\" to Berkeley by William Jolitz. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)boot_i386.8 8.2 (Berkeley) 4/19/94 36.\" 37.Dd April 19, 1994 38.Dt BOOT 8 i386 39.Os 40.Sh NAME 41.Nm boot 42.Nd 43system bootstrapping procedures 44.Sh DESCRIPTION 45.Sy Power fail and crash recovery. 46Normally, the system will reboot itself at power-up or after crashes. 47An automatic consistency check of the file systems will be performed, 48and unless this fails, the system will resume multi-user operations. 49.Pp 50.Sy Cold starts. 51The 386 52.Tn "PC AT" 53clones attempt to boot the floppy disk drive A (otherwise known as drive 540) first, and failing that, attempt to boot the hard disk C (otherwise 55known as hard disk controller 1, drive 0). 56The automatic boot will attempt to load 57.Pa kernel 58from partition A of either the floppy or the hard disk. 59This boot may be aborted by typing any character on the keyboard repeatedly 60(four or five times at least) during the operating system load phase, after 61which the bootstrap will prompt for the file that you wish to load instead. 62.Pp 63One exception to this is the 64.Ql d 65key, which will not abort the load but instead silently force the 66.Dv DEBUG 67boot flags. 68The boot flags for an autoboot are 0, and 3 for the successive boot after 69an aborted autoboot sequence. 70No other provison is made for setting boot flags (yet). 71A specific device or bootstrap file may be used; for example, 72.Pp 73The file specifications used for the boostrap 74when loaded with the 75.Dq askme 76flag 77(e.g. an aborted autoboot) 78are of the form: 79.Pp 80.Dl device unit partition: 81.Pp 82where 83.Ar device 84is the type of the device, assumed to be on the ISA bus, to be searched, 85.Ar unit 86is the unit number of the disk or tape, 87and 88.Ar partition 89is the disk partition or tape file number. 90Normal line editing characters can be used when typing the file specification. 91The following list of supported devices may vary from installation to 92installation: 93.Bd -unfilled -offset indent 94wd ST506, IDE, ESDI, RLL disks on a WD100[2367] or lookalike 95 controller 96fd 5 1/4" or 3 1/2" High density floppies 97.Ed 98.Pp 99For example, 100to boot from a file system which starts at cylinder 0 101of unit 0 of an IDE disk, type 102.Dq Li wd0a:kernel 103to the boot prompt; 104.Dq Li fd0a:kernel 105would specify a 3 1/2" floppy drive 0 . 106.Pp 107In an emergency, the bootstrap methods described in the paper 108.%T "Installing and Operating 4.3 BSD-Reno UNIX on the AT/386" 109can be used 110to boot from a distribution tape. 111.Sh FILES 112.Bl -tag -width /kernelxx -compact 113.It Pa /kernel 114system code 115.It Pa /boot 116system bootstrap 117.El 118.Sh SEE ALSO 119.Xr halt 8 , 120.Xr reboot 8 , 121.Xr shutdown 8 122.Sh BUGS 123The disklabel format used by this version of 124.Bx 125is quite 126different from that of other architectures. 127