ISOBOOT(7) Standards, Environments, and Macros ISOBOOT(7)

NAME


isoboot - Boot code for hybrid ISO/USB images on BIOS-based computers

DESCRIPTION


isoboot is used on BIOS-based computers to boot from an ISO image that has
been written to a USB flash drive or other HDD-like device. isoboot is
installed in a x86 Boot partition with installboot(8).

IMPLEMENTATION NOTES


The El Torito standard for bootable CDs provides a 32KB "System Area" at
the beginning of an image. To create an image that is able to be booted by
the BIOS as either a CD-ROM ("ISO") and as a more HDD-like image (e.g. on a
USB flash drive) it is necessary to have both a standard El Torito boot
catalog containing a HDD-style partition table and boot code. isoboot is
intended to be placed in a MBR x86 boot partition to allow the system to
find the standard FreeBSD loader(7) in the ISO filesystem later in the
image.

BOOTING


isoboot looks for an ISO filesystem image on the device it was booted from
and seeks to read the primary illumos loader(7) from there.

SEE ALSO


installboot(8)

HISTORY


isoboot appeared in FreeBSD 12.0.

AUTHORS


This manual page written by Benno Rice <benno@FreeBSD.org>.

illumos March 30, 2018 illumos