CDBOOT(8) - System Manager’s Manual (amd64) #

CDBOOT(8) - System Manager’s Manual (amd64)

NAME #

cdboot - amd64-specific second-stage CD-specific bootstrap

DESCRIPTION #

cdboot is a modified version of the amd64 second-stage bootstrap program, boot(8), configured to be run by the OpenBSD El Torito CD-ROM boot sector cdbr. cdboot will look for an /etc/boot.conf configuration file on the CD-ROM. If it finds one, it processes the commands within it. boot.conf processing can be skipped by holding down either Control key as cdboot starts.

cdboot then sits in a loop, processing commands given by the user. It accepts all the commands accepted by boot(8).

If no commands are given for a short time, cdboot will then attempt to load an OpenBSD kernel from the CD. It first looks for the install kernel bsd.rd in the standard amd64 release directory (e.g. /3.6/amd64/bsd.rd), then for /bsd. It may be told to boot an alternative kernel, either by commands in the boot.conf file, or by commands typed by the user at the boot> prompt.

FILES #

/usr/mdec/cdboot

CD-specific second-stage bootstrap

/etc/boot.conf

cdboot configuration file (read from CD)

EXAMPLES #

Boot the install kernel:

boot> bsd.rd

SEE ALSO #

boot(8), boot_amd64(8), mkhybrid(8)

STANDARDS #

Curtis E. Stevens, Stan Merkin, El Torito Bootable CD-ROM Format Specification, Version 1.0, January 25, 1995.

HISTORY #

The cdboot program first appeared in OpenBSD 3.6.

CAVEATS #

By default, many CD creation programs restrict filenames to the MS-DOS 8.3 format. Unless this is changed, cdboot will not be able to read its boot.conf(8) file. For example, with mkhybrid(8) the -l option should be specified.

BUGS #

The ls command does not work on ISO 9660 (cd9660) filesystems, which are used on most CDs.

OpenBSD 7.5 - March 30, 2016