1.\" Copyright (c) 1990, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Systems Programming Group of the University of Utah Computer 6.\" 7.\" Science Department. 8.\" %sccs.include.redist.man% 9.\" 10.\" @(#)boot_hp300.8 5.3 (Berkeley) 04/20/91 11.\" 12.Dd 13.Dt REBOOT 8 14.Os BSD 4.4 15.Sh NAME 16.Nm reboot 17.Nd 18.Tn UNIX 19bootstrapping procedures 20.Sh SYNOPSIS 21.Nm reboot 22.Op Fl d 23.Op Fl n 24.Op Fl q 25.Op Fl s 26.Sh DESCRIPTION 27.Tn UNIX 28is started by placing it at the beginning of physical memory 29and transferring to the entry point. 30Since the system is not reenterable, 31it is necessary to read it in from disk or tape 32each time it is to be bootstrapped. 33.Pp 34.Sy Rebooting a running system . 35When a 36.Tn UNIX 37is running and a reboot is desired, 38.Xr shutdown 8 39is normally used. 40If there are no users then 41.Nm reboot 42can be used. 43Reboot causes the disks to be synced and allows the system 44to perform other shutdown activities such as resynchronizing 45hardware time-of-day clocks. 46A multi-user reboot (as described below) is then initiated. 47This causes a system to be 48booted and an automatic disk check to be performed. If all this succeeds 49without incident, the system is then brought up for many users. 50.Pp 51Options to reboot are: 52.Bl -tag -width Ds 53.\" .It Fl d 54.\" option forces a memory dump to the swap area (see 55.\" .Xr crash 8 ) 56.\" before rebooting. 57.\" This can be used if the system is in a funny state that you would 58.\" like to ``snapshot'' and analyze later. 59.It Fl n 60option avoids the sync. It can be used if a disk or the processor 61is on fire. 62.It Fl q 63reboots quickly and ungracefully, without shutting down running 64processes first. 65.\" .It Fl s 66.\" option reboots to single user mode. 67.El 68.Pp 69.Nm Reboot 70normally logs the reboot using 71.Xr syslog 8 72and places a shutdown record in the login accounting file (see 73.Xr utmp 5 . 74These actions are inhibited if the 75.Fl n 76or 77.Fl q 78options are present. 79.Pp 80.Sy Power fail and crash recovery. 81Normally, the system will reboot itself at power-up or after crashes. 82An automatic consistency check of the file systems will be performed, 83and unless this fails, the system will resume multi-user operations. 84.Pp 85.Sy Cold starts. 86On an HP300, the boot procedure uses the boot rom to load a boot program 87from an 88.Tn LIF 89format directory at the beginning of an attached disk. 90The 91.Pa /usr/mdec 92directory contains a disk boot program 93.Pa bootrd 94which should be placed in a new pack automatically by 95.Xr newfs 8 96when the ``a'' partition file system on the pack is created. 97.Pp 98This 99.Em boot 100program 101finds the corresponding file on the given device 102.Pf ( Ar vmunix 103by default), 104loads that file into memory, 105and starts the program at the entry address specified in the program header. 106.Pp 107The boot program can be interrupted by typing `^C' (ctrl-C). 108This will force the boot program to interactively prompt for a system to boot. 109If not interrupted, it will boot from the device from which the boot 110program itself was loaded. 111.Pp 112The file specifications used for an interactive boot are of the form: 113.Pp 114.Dl device(unit,minor) 115.Pp 116where 117.Ar device 118is the type of the device to be searched, 119.Ar unit 120is 8 * the hpib number plus the unit number of the disk or tape, 121and 122.Ar minor 123is the disk partition or tape file number. 124Normal line editing characters can be used when typing the file specification. 125Currently, ``rd'' is the only valid 126.Ar device 127specifier. 128.Pp 129For example, 130to boot from the `a' file system of unit 0 on HP-IB 2, 131type 132.Ql rd(16,0)vmunix 133to the boot prompt. 134For tapes, the minor device number gives a file offset. 135.Pp 136In an emergency, the bootstrap methods described in the paper 137.%T Installing 4.3bsd on the HP300 138can be used to boot from a distribution tape. 139.Sh FILES 140.Bl -tag -width /usr/mdec/installboot -compact 141.It Pa /vmunix 142system code 143.It Pa /usr/mdec/bootrd 144.Tn LIF 145format boot block 146.It Pa /usr/mdec/installboot 147program to install boot blocks 148.El 149.Sh SEE ALSO 150.Xr crash 8m , 151.Xr fsck 8 , 152.Xr halt 8 , 153.Xr init 8 , 154.Xr newfs 8 , 155.Xr rc 8 , 156.Xr shutdown 8 , 157.Xr syslogd 8 158.Sh HISTORY 159The 160.Nm 161command is 162.Ud . 163