reboot.tproj/boot_i386.8

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  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
  43 system bootstrapping procedures
  44 .Sh DESCRIPTION
  45 .Sy Power fail and crash recovery.
  46 Normally, the system will reboot itself at power-up or after crashes.
  47 An automatic consistency check of the file systems will be performed,
  48 and unless this fails, the system will resume multi-user operations.
  49 .Pp
  50 .Sy Cold starts.
  51 The 386
  52 .Tn "PC AT"
  53 clones attempt to boot the floppy disk drive A (otherwise known as drive
  54 0) first, and failing that, attempt to boot the hard disk C (otherwise
  55 known as hard disk controller 1, drive 0).
  56 The automatic boot will attempt to load
  57 .Pa vmunix
  58 from partition A of either the floppy or the hard disk.
  59 This 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
  61 which the bootstrap will prompt for the file that you wish to load instead.
  62 .Pp
  63 One exception to this is the
  64 .Ql d
  65 key, which will not abort the load but instead silently force the
  66 .Dv DEBUG
  67 boot flags.
  68 The boot flags for an autoboot are 0, and 3 for the successive boot after
  69 an aborted autoboot sequence.
  70 No other provison is made for setting boot flags (yet).
  71 A specific device or bootstrap file may be used; for example,
  72 .Pp
  73 The file specifications used for the boostrap
  74 when loaded with the
  75 .Dq askme
  76 flag
  77 (e.g. an aborted autoboot)
  78 are of the form:
  79 .Pp
  80 .Dl device unit partition:
  81 .Pp
  82 where
  83 .Ar device
  84 is the type of the device, assumed to be on the ISA bus, to be searched,
  85 .Ar unit
  86 is the unit number of the disk or tape,
  87 and
  88 .Ar partition
  89 is the disk partition or tape file number.
  90 Normal line editing characters can be used when typing the file specification.
  91 The following list of supported devices may vary from installation to
  92 installation:
  93 .Bd -unfilled -offset indent
  94 wd      ST506, IDE, ESDI, RLL disks on a WD100[2367] or lookalike
  95         controller
  96 fd      5 1/4" or 3 1/2" High density floppies
  97 .Ed
  98 .Pp
  99 For example,
 100 to boot from a file system which starts at cylinder 0
 101 of unit 0 of an IDE disk, type
 102 .Dq Li wd0a:vmunix
 103 to the boot prompt;
 104 .Dq Li fd0a:vmunix
 105 would specify a 3 1/2" floppy drive 0 .
 106 .Pp
 107 In an emergency, the bootstrap methods described in the paper
 108 .%T "Installing and Operating 4.3 BSD-Reno UNIX on the AT/386"
 109 can be used
 110 to boot from a distribution tape.
 111 .Sh FILES
 112 .Bl -tag -width /vmunixxx -compact
 113 .It Pa /vmunix
 114 system code
 115 .It Pa /boot
 116 system bootstrap
 117 .El
 118 .Sh SEE ALSO
 119 .Xr halt 8 ,
 120 .Xr reboot 8 ,
 121 .Xr shutdown 8
 122 .Sh BUGS
 123 The disklabel format used by this version of
 124 .Bx
 125 is quite
 126 different from that of other architectures.