1.\" Copyright (c) 1980, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)boot_tahoe.8 6.4 (Berkeley) 03/16/91 7.\" 8.Dd 9.Dt REBOOT 8 10.Os BSD 4 11.Sh NAME 12.Nm reboot 13.Nd 14.Tn UNIX 15bootstrapping procedures 16.Sh SYNOPSIS 17.Nm reboot 18.Op Fl n 19.Op Fl q 20.Sh DESCRIPTION 21.Pp 22.Tn UNIX 23is started by placing it in memory 24at location zero and transferring to the entry point. 25Since the system is not reenterable, 26it is necessary to read it in from disk or tape 27each time it is to be bootstrapped. 28.Pp 29.Sy Rebooting a running system . 30When a 31.Tn UNIX 32is running and a reboot is desired, 33.Xr shutdown 8 34is normally used. 35If there are no users then 36.Nm reboot 37can be used. 38Reboot causes the disks to be synced and allows the system 39to perform other shutdown activities such as resynchronizing 40hardware time-of-day clocks. 41A multi-user reboot (as described below) is then initiated. 42This causes a system to be 43booted and an automatic disk check to be performed. If all this succeeds 44without incident, the system is then brought up for many users. 45.Pp 46Options to reboot are: 47.Bl -tag -width Ds 48.It Fl n 49option avoids the sync. It can be used if a disk or the processor 50is on fire. 51.It Fl q 52reboots quickly and ungracefully, without shutting down running 53processes first. 54.El 55.Pp 56.Nm Reboot 57normally logs the reboot using 58.Xr syslog 8 59and places a shutdown record in the login accounting file 60.Pa /var/log/wtmp. 61These actions are inhibited if the 62.Fl n 63or 64.Fl q 65options are present. 66.Pp 67.Sy Power fail and crash recovery. 68Normally, the system will reboot itself at power-up or after crashes. 69An automatic consistency check of the file systems will be performed 70as described in 71.Xr fsck 8 . 72and unless this fails, the system will resume multi-user operations. 73.Pp 74.Sy Cold starts . 75These are processor-type dependent. 76On the 77.Tn CCI 78Power 6/32 and related processors, 79the system will do a standard autoboot from drive 0 80upon power-up or reset. 81This automatic boot may be cancelled by typing a 82.Ql \&# 83in the first few seconds after reset. 84This enters console mode; the console prompt is 85.Ql > 86or 87.Ql \&# . 88The boot flags can be set to any hexadecimal value 89.Fl n 90with the command 91.Pp 92.Bd -filled -offset indent -compact 93.Li \&#> p23 94.Ar n . 95.Ed 96.Pp 97The default device may be examined or set; see the Diagnostics and Debugging 98manual for the processor for details on device naming and syntax. 99After setting the boot flags and/or device, 100a bootstrap sequence can be initiated with 101.Pp 102.Dl #> fb 103.Pp 104A specific device or bootstrap file may be used; for example, 105.Pp 106.Dl \&#> \&fb xfd(1,0) 107.Pp 108would boot from the `a' partition on 109.Tn XFD 110drive 1. 111.Pp 112The file specifications used for the boostrap 113when loaded with the 114.Dq askme 115flag 116(register 23 set to 1 or 3) 117are of the form: 118.Pp 119.Dl device(adaptor,controller,unit,minor) 120.Pp 121where 122.Ar device 123is the type of the device to be searched, 124.Ar adaptor 125is number of the 126.Tn VERSAbus 127(or 128.Tn VMEbus ) 129to which the device is attached, 130.Ar controller 131is the unit number of the controller on that buss, 132.Ar unit 133is the unit number of the disk or tape, 134and 135.Ar minor 136is the disk partition or tape file number. 137Leading adaptor or controller numbers default to 0. 138Normal line editing characters can be used when typing the file specification. 139The following list of supported devices may vary from installation to 140installation: 141.Pp 142.Bd -unfilled -offset indent -compact 143dk SMD or ESDI disks on VDDC or SMD-E 144cy tape on Ciprico Tapemaster controller 145.Ed 146.Pp 147For example, 148to boot from a file system which starts at cylinder 0 149of unit 0 of an 150.Tn SMD-E 151disk, type 152.Ql dk(0,0)vmunix 153to the boot prompt; 154.Ql dk(2,1,0)vmunix 155would specify drive 1 on 156.Tn SMD-E 157controller 2. 158.Pp 159In an emergency, the bootstrap methods described in the paper 160.%T "Installing and Operating 4.3 BSD-tahoe UNIX on the Tahoe" 161can be used 162to boot from a distribution tape. 163.Sh FILES 164.Bl -tag -width /vmunix -compact 165.It Pa /vmunix 166system code 167.It Pa /boot 168system bootstrap 169.El 170.Sh SEE ALSO 171.Xr crash 8 , 172.Xr disklabel 8 , 173.Xr fsck 8 , 174.Xr halt 8 , 175.Xr init 8 , 176.Xr rc 8 , 177.Xr shutdown 8 , 178.Xr syslogd 8 179.Sh BUGS 180The disklabel format used by some versions of the console processor 181is different than the format used by 182.Tn UNIX 183and the bootstrap. 184.Sh HISTORY 185The 186.Nm 187command 188.Ud 189