DOSBOOT(8) | System Manager's Manual (x86) | DOSBOOT(8)

# NAME

`dosboot` —
boot NetBSD/x86 from DOS

# SYNOPSIS

`dosboot` | [`-u`] [`-c` command] [`-i`] [path [`-adqsv`]]

# DESCRIPTION

`dosboot` is an MS-DOS program. It is a boot loader for NetBSD/x86 designed to permit NetBSD to be booted directly from MS-DOS. By default, it boots a file with name NETBSD in the current MS-DOS directory. `dosboot` shares common code with the standard boot loader, x86/boot(8).

The recognized options are:

`-c`
  Execute command (see below).
`-i`
  Enter interactive mode. `dosboot` will present a prompt, allowing input of commands (see below).
`-u`
  Boot from a UFS file system instead of an MS-DOS file system.
path
  Specifies the kernel file. In MS-DOS mode (default) a normal MS-DOS filename (with or without drive specification) is accepted. In UFS mode (after `-u` or after a `mode ufs` command), a path in a NetBSD file system is expected. By default, the file is looked up in partition ‘a’ of the first hard disk. Another device or partition can be specified by prepending a block device name in terms of NetBSD, followed by a colon (see x86/boot(8) and examples).
`-1234abcdmqsvxz`
  Flags passed to the kernel, see x86/boot(8).

See x86/boot(8) for commands accepted after the `-c` flag or in interactive mode.

`dosboot` is also installed in the release(7) hierarchy, under installation/misc/dosboot.com.

# FILES

/usr/mdec/dosboot.com

# EXAMPLES

To boot a NetBSD kernel located on MS-DOS drive D, one would issue:

    dosboot D:\NODOS\NETBSD

To boot from a NetBSD floppy into single user mode, type e.g.:

    dosboot -u fd0a:netbsd -s

# SEE ALSO

release(7), x86/boot(8)

# HISTORY

The NetBSD/x86 `dosboot` command first appeared in NetBSD 1.3.

# BUGS

`dosboot` assumes that the processor is in real mode at startup. It does not work well in the presence of MS-DOS extenders and memory managers.

`dosboot` does not run directly under Windows 95.

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 NetBSD kernel.

In MS-DOS mode, no useful boot device specification is passed to NetBSD. It is necessary to have the root device hardwired into the kernel configuration or to enter it manually.

February 17, 2017 | NetBSD 9.5