projects / unix-history / blame
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|---|---|---|
| 49177589 WN |
1 | .\" Copyright (c) 1990 The Regents of the University of California. |
| 2 | .\" All rights reserved. | |
| 3 | .\" | |
| 4 | .\" This code is derived from software written and contributed | |
| 5 | .\" to Berkeley by William Jolitz. | |
| 6 | .\" | |
| 7 | .\" %sccs.include.redist.man% | |
| 8 | .\" | |
| 9 | .\" @(#)boot_i386.8 1.1 (Berkeley) %G% | |
| 10 | .\" | |
| 11 | .TH REBOOT 8 "December 12, 1990" | |
| 12 | .SH NAME | |
| 13 | reboot \- UNIX bootstrapping procedures | |
| 14 | .SH SYNOPSIS | |
| 15 | .B reboot | |
| 16 | [ | |
| 17 | .B \-n | |
| 18 | ] [ | |
| 19 | .B \-q | |
| 20 | ] | |
| 21 | .SH DESCRIPTION | |
| 22 | .PP | |
| 23 | UNIX, an ordinary executable file, | |
| 24 | is placed into memory by bootstrap at location absolute zero, and | |
| 25 | entered at the executable's entry point (a_entry). | |
| 26 | Upon startup, the system reorganizes memory to suit the needs of | |
| 27 | the hardware configuration found, thus it is not designed to | |
| 28 | be restartable without being reloaded on reboot. | |
| 29 | Each time it is to be bootstrapped, it must be reloaded, usually from | |
| 30 | a disk file. | |
| 31 | .PP | |
| 32 | .B Rebooting a running system. | |
| 33 | When a UNIX is running and a reboot is desired, | |
| 34 | .IR shutdown (8) | |
| 35 | is normally used. | |
| 36 | If there are no users then | |
| 37 | .B reboot | |
| 38 | can be used. | |
| 39 | Reboot causes the disks to be synced and allows the system | |
| 40 | to perform other shutdown activities such as resynchronizing | |
| 41 | hardware time-of-day clocks. | |
| 42 | A multi-user reboot (as described below) is then initiated. | |
| 43 | This causes a system to be | |
| 44 | booted and an automatic disk check to be performed. If all this succeeds | |
| 45 | without incident, the system is then brought up for many users. | |
| 46 | .PP | |
| 47 | Options to reboot are: | |
| 48 | .TP | |
| 49 | .B \-n | |
| 50 | option avoids the sync. It can be used if a disk or the processor | |
| 51 | is on fire. | |
| 52 | .TP | |
| 53 | .B \-q | |
| 54 | reboots quickly and ungracefully, without shutting down running | |
| 55 | processes first. | |
| 56 | .PP | |
| 57 | .I Reboot | |
| 58 | normally logs the reboot using | |
| 59 | .IR syslog (8) | |
| 60 | and places a shutdown record in the login accounting file | |
| 61 | /var/log/wtmp. | |
| 62 | These actions are inhibited if the | |
| 63 | .B \-n | |
| 64 | or | |
| 65 | .B \-q | |
| 66 | options are present. | |
| 67 | .PP | |
| 68 | .B "Power fail and crash recovery." | |
| 69 | Normally, the system will reboot itself at power-up or after crashes. | |
| 70 | An automatic consistency check of the file systems will be performed | |
| 71 | as described in | |
| 72 | .IR fsck (8). | |
| 73 | and unless this fails, the system will resume multi-user operations. | |
| 74 | .PP | |
| 75 | .B Cold starts. | |
| 76 | The 386 PC AT clones attempt to boot the floppy disk drive A (otherwise | |
| 77 | known as drive 0) first, and failing that, attempt to boot the hard disk | |
| 78 | C (otherwise known as hard disk controller 1, drive 0). | |
| 79 | The automatic boot will attempt to load \fIvmunix\fP from partition A of | |
| 80 | either the floppy or the hard disk. This boot may be aborted by typing | |
| 81 | any character on the keyboard repeatedly (four or five times at least) | |
| 82 | during the operating system load phase, after which the bootstrap will | |
| 83 | prompt for the file that you wish to load instead. | |
| 84 | .LP | |
| 85 | One exception to this is the 'd' key, which will not abort the load but | |
| 86 | instead silently force the DEBUG boot flags. The boot flags for an autoboot | |
| 87 | are 0, and 3 for the successive boot after an aborted autoboot sequence. | |
| 88 | No other provison is made for setting boot flags (yet). | |
| 89 | A specific device or bootstrap file may be used; for example, | |
| 90 | .IP | |
| 91 | The file specifications used for the boostrap | |
| 92 | when loaded with the \*(lqaskme\*(rq flag | |
| 93 | (e.g. an aborted autoboot) | |
| 94 | are of the form: | |
| 95 | .IP | |
| 96 | device unit partition: | |
| 97 | .PP | |
| 98 | where | |
| 99 | .I device | |
| 100 | is the type of the device, assumed to be on the ISA bus, to be searched, | |
| 101 | .I unit | |
| 102 | is the unit number of the disk or tape, | |
| 103 | and | |
| 104 | .I partition | |
| 105 | is the disk partition or tape file number. | |
| 106 | Normal line editing characters can be used when typing the file specification. | |
| 107 | The following list of supported devices may vary from installation to | |
| 108 | installation: | |
| 109 | .LP | |
| 110 | .ta 5 10 | |
| 111 | .nf | |
| 112 | wd ST506, IDE, ESDI, RLL disks on a WD100[2367] or lookalike | |
| 113 | controller | |
| 114 | fd 5 1/4" or 3 1/2" High density floppies | |
| 115 | .fi | |
| 116 | .PP | |
| 117 | For example, | |
| 118 | to boot from a file system which starts at cylinder 0 | |
| 119 | of unit 0 of an IDE disk, type \*(lqwd0a:vmunix\*(rq | |
| 120 | to the boot prompt; \*(lqfd0a:vmunix\*(rq | |
| 121 | would specify a 3 1/2" floppy drive 0 . | |
| 122 | .PP | |
| 123 | In an emergency, the bootstrap methods described in the paper | |
| 124 | ``Installing and Operating 4.3BSD-Reno UNIX on the AT/386'' can be used | |
| 125 | to boot from a distribution tape. | |
| 126 | .SH FILES | |
| 127 | .ta \w'/vmunix 'u | |
| 128 | /vmunix system code | |
| 129 | .br | |
| 130 | /boot system bootstrap | |
| 131 | .SH "SEE ALSO" | |
| 132 | crash(8), | |
| 133 | disklabel(8), | |
| 134 | fsck(8), | |
| 135 | halt(8), | |
| 136 | init(8), | |
| 137 | rc(8), | |
| 138 | shutdown(8), | |
| 139 | syslogd(8) | |
| 140 | .SH BUGS | |
| 141 | The disklabel format used by this version of 4.3BSD-Reno is quite | |
| 142 | different from that of other architectures. Too bad. |