7acb51f681
This is part of a project for adding the ability to create hybrid CD/USB boot images. In the BIOS case when booting from something that isn't a CD we need some extra boot code to actually find our next stage (loader) within an ISO9660 filesystem. This code will reside in a GPT partition (similar to gptboot(8) from which it is derived) and looks for /boot/loader in an ISO9660 filesystem on the image. Reviewed by: imp Sponsored by: iXsystems, Inc. Differential Revision: https://reviews.freebsd.org/D14914
70 lines
2.5 KiB
Groff
70 lines
2.5 KiB
Groff
.\" Copyright (c) 2018 iXsystems, Inc.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd March 30, 2018
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.Dt ISOBOOT 8
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.Os
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.Sh NAME
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.Nm isoboot
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.Nd Boot code for hybrid ISO/USB images on BIOS-based computers
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.Sh DESCRIPTION
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.Nm
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is used on BIOS-based computers to boot from an ISO image that has
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been written to a USB flash drive or other HDD-like device.
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.Nm
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is installed in a
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.Cm freebsd-boot
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partition with
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.Xr mkimg 1 .
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.Sh IMPLEMENTATION NOTES
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The El Torito standard for bootable CDs provides a 32KB "System Area"
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at the beginning of an image.
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To create an image that is able to be booted by the BIOS as either a
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CD-ROM ("ISO") and as a more HDD-like image (e.g. on a USB flash drive)
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it is necessary to have both a standard El Torito boot catalog
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containing a HDD-style partition table and boot code.
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.Nm
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is intended to be placed in a GPT partition to allow the system to find
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the standard
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.Fx
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.Xr loader 8
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in the ISO filesystem later in the image.
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.Sh BOOTING
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.Nm
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looks for an ISO filesystem image on the device it was booted from and
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seeks to read either the primary
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.Fx
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.Xr loader 8
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or kernel from there.
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.Sh SEE ALSO
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.Xr mkimg 1
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.Sh HISTORY
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.Nm
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appeared in FreeBSD 12.0.
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.Sh AUTHORS
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This manual page written by
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.An Benno Rice Aq benno@FreeBSD.org .
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