cdboot8

Overview

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

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.