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boot0cfg(8)

NAME

     boot0cfg -- boot manager installation/configuration utility

SYNOPSIS

     boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask] [-o options]
	      [-s slice] [-t ticks] disk

DESCRIPTION

     The FreeBSD `boot0' boot manager permits the operator to select from
     which disk and slice an i386 machine (PC) is booted.

     Note that what are referred to here as ``slices'' are typically called
     ``partitions'' in non-BSD documentation relating to the PC.  Typically,
     only non-removable disks are sliced.

     The boot0cfg utility optionally installs the `boot0' boot manager on the
     specified disk; and allows various operational parameters to be config-
     ured.

     On PCs, a boot manager typically occupies sector 0 of a disk, which is
     known as the Master Boot Record (MBR).  The MBR contains both code (to
     which control is passed by the PC BIOS) and data (an embedded table of
     defined slices).

     The options are:

     -B      Install the `boot0' boot manager.	This option causes MBR code to
	     be replaced, without affecting the embedded slice table.

     -b boot0
	     Specify which `boot0' image to use.  The default is /boot/boot0
	     which will use the video card as output, alternatively
	     /boot/boot0sio can be used for output to the COM1 port.  (Be
	     aware that nothing will be output to the COM1 port unless the
	     modem signals DSR and CTS are active.)

     -d drive
	     Specify the drive number used by the PC BIOS in referencing the
	     drive which contains the specified disk.  Typically this will be
	     0x80 for the first hard drive, 0x81 for the second hard drive,
	     and so on; however any integer between 0 and 0xff is acceptable
	     here.

     -f file
	     Specify that a backup copy of the preexisting MBR should be writ-
	     ten to file.  This file is created if it does not exist, and
	     replaced if it does.

     -m mask
	     Specify slices to be enabled/disabled, where mask is an integer
	     between 0 (no slices enabled) and 0xf (all four slices enabled).

     -o options
	     A comma-separated string of any of the following options may be
	     specified (with ``no'' prepended as necessary):

	     packet  Use the disk packet (BIOS INT 0x13 extensions) interface,

	     update  Allow the MBR to be updated by the boot manager.  (The
		     MBR may be updated to flag slices as `active', and to
		     save slice selection information.)  This is the default;
		     a `noupdate' option causes the MBR to be treated as read-
		     only.

     -s slice
	     Set the default boot selection to slice.  Values between 1 and 4
	     refer to slices; a value of 5 refers to the option of booting
	     from a second disk.

     -t ticks
	     Set the timeout value to ticks.  (There are approximately 18.2
	     ticks per second.)

     -v      Verbose: display information about the slices defined, etc.

FILES

     /boot/boot0     The default `boot0' image
     /boot/boot0sio  Image for serial consoles (COM1,9600,8,N,1,MODEM)

EXAMPLES

     To boot slice 2 on the next boot:

	   boot0cfg -s 2 ad0

     To enable just slices 1 and 2 in the menu:

	   boot0cfg -m 0x3 ad0

DIAGNOSTICS

     The boot0cfg utility exits 0 on success, and >0 if an error occurs.

SEE ALSO

     boot(8), fdisk(8)

AUTHORS

     Robert Nordier <rnordier@FreeBSD.org>.

BUGS

     Use of the `packet' option may cause `boot0' to fail, depending on the
     nature of BIOS support.

     Use of the `setdrv' option with an incorrect -d operand may cause the MBR
     to be written to the wrong disk.  Be careful!

FreeBSD 5.4		       February 21, 1999		   FreeBSD 5.4

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