NAME    [Toc]    [Back]

     boot0cfg -- boot manager installation/configuration utility

SYNOPSIS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

     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 configured.


     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.

     -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 written
 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,
		     as opposed to the legacy (CHS) interface, when doing disk
		     I/O.  This allows booting above cylinder 1023, but
		     requires specific BIOS support.  The default is
		     `nopacket'.

	     setdrv  Forces the drive containing the disk to be referenced
		     using drive number definable by means of the -d option.
		     The default is `nosetdrv'.

	     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 readonly.


     -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    [Toc]    [Back]

     /boot/boot0  The default `boot0' image

EXAMPLES    [Toc]    [Back]

     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    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

     boot(8), fdisk(8)

AUTHORS    [Toc]    [Back]

     Robert Nordier <[email protected]>.

BUGS    [Toc]    [Back]

     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 5.2.1		       February 21, 1999		 FreeBSD 5.2.1