man8/man8.x86/dosboot.8

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.\" 	Matthias Drochner.  All rights reserved.
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.\"     @(#)boot_i386.8	8.2 (Berkeley) 4/19/94
.\"
.Dd February 17, 2017
.Dt DOSBOOT 8 x86
.Os
.Sh NAME
.Nm dosboot
.Nd boot NetBSD/x86 from DOS
.Sh SYNOPSIS
.Nm
.Op Fl u
.Op Fl c Ar command
.Op Fl i
.Op Ar path Op Fl adqsv
.Sh DESCRIPTION
.Nm
is an
.Tn MS-DOS
program.
It is a boot loader for
.Nx Ns Tn /x86
designed to permit
.Nx
to be booted directly from
.Tn MS-DOS .
By default, it boots a file with name
.Pa NETBSD
in the current
.Tn MS-DOS
directory.
.Nm
shares common code with the standard boot loader,
.Xr x86/boot 8 .
.Pp
The recognized options are:
.Bl -tag -width "-adqsv" -offset 04n
.It Fl c
Execute
.Ar command
(see below).
.It Fl i
Enter interactive mode.
.Nm
will present a prompt, allowing input of commands (see below).
.It Fl u
Boot from a UFS file system instead of an
.Tn MS-DOS
file system.
.It Ar path
Specifies the kernel file.
In
.Tn MS-DOS
mode (default) a normal
.Tn MS-DOS
filename (with or without drive specification) is accepted.
In UFS mode (after
.Fl u
or after a
.Ic mode ufs
command), a path in a
.Nx
file system is expected.
By default, the file is looked up in partition
.Sq a
of the first hard disk.
Another device or partition can be specified
by prepending a block device name in terms of
.Nx ,
followed by a colon (see
.Xr x86/boot 8
and examples).
.It Fl 1234abcdmqsvxz
Flags passed to the kernel, see
.Xr x86/boot 8 .
.El
.Pp
See
.Xr x86/boot 8
for commands accepted after the
.Fl c
flag or in interactive mode.
.Pp
.Nm
is also installed in the
.Xr release 7
hierarchy, under
.Pa installation/misc/dosboot.com .
.Sh FILES
.Pa /usr/mdec/dosboot.com
.Sh EXAMPLES
To boot a
.Nx
kernel located on
.Tn MS-DOS
drive D, one would issue:
.Bd -literal -offset indent
dosboot D:\eNODOS\eNETBSD
.Ed
.Pp
To boot from a
.Nx
floppy into single user mode, type e.g.:
.Bd -literal -offset indent
dosboot -u fd0a:netbsd -s
.Ed
.Sh SEE ALSO
.Xr release 7 ,
.Xr x86/boot 8
.Sh HISTORY
The
.Nx Ns Tn /x86
.Nm
command first appeared in
.Nx 1.3 .
.Sh BUGS
.Nm
assumes that the processor is in real mode at startup.
It does not work well in the presence of
.Tn MS-DOS
extenders and memory managers.
.Pp
.Nm
does not run directly under
.Tn Windows 95 .
.Pp
In UFS mode, files can only be loaded from devices known to the BIOS.
The device names do not necessarily comply with the names later
used by the booted
.Nx
kernel.
.Pp
In
.Tn MS-DOS
mode, no useful boot device specification is passed to
.Nx .
It is necessary to have the root device hardwired into the kernel
configuration or to enter it manually.