Making HFS bootable CDs

It *may* be possible to make the hybrid CD bootable on a Mac. As I do not
have easy access to a CD-R (nor a Mac) at the moment, I have not actually
created and written a bootable hybrid to CD - however, I *think* it will work!

A bootable HFS CD requires an Apple CD-ROM (or compatible) driver, a bootable
HFS partition and the necessary System, Finder, etc. files.

A driver can be obtained from any other Mac bootable CD-ROM using the
"apple_driver" utility (to make, type "make apple_driver"). This file can
then be used with the -boot-hfs-file option. See below for usage.

The HFS partition (i.e. the hybrid disk in our case) must contain a
suitable System Folder, again from another CD-ROM or disk.

For a partition to be bootable, it must have it's "boot block" set. The boot
block is in the first two blocks of a partition. For a non-bootable partition
the boot block is full of zeros. Normally, when a System file is copied to
partition on a Mac disk, the boot block is filled with a number of required
settings - unfortunately I don't know the full spec for the boot block ...

I'm guessing that this will work OK ...

Therefore, the utility "apple_driver" also extracts the boot block from the
first HFS partition it finds on the given CD-ROM and this is used for the
HFS partition created by mkhybrid.

To extract the driver and boot block:

apple_driver CDROM_device > HFS_driver_file

where CDROM_device is the device name used by the CD-ROM (e.g. /dev/cdrom)

The format of the HFS driver file is:

	HFS CD Label Block                              512 bytes
	Driver Partition Map (for 2048 byte blocks)     512 bytes
	Driver Partition Map (for 512 byte blocks)      512 bytes
	Empty                                           512 bytes
	Driver Partition                                N x 2048 bytes
	HFS Partition Boot Block                        1024 bytes

The Perl script "hdisk.pl" can be used to give a listing of what's on
a Mac CD. hdisk.pl is part of hfsutils.

A hybrid CD is made using the option "-boot-hfs-file" e.g.

mkhybrid -boot-hfs-file HFS_driver_file -o hfs.raw src_files/

The -boot-hfs-file implies the -hfs option.

PLEASE NOTE:

By using a driver from an Apple CD and copying Apple software to your CD,
you become liable to obey Apple Computer, Inc. Software License Agreements.

The driver code (both extracting the driver and creating partitions etc.
is based on code from "mkisofs 1.05 PLUS" by Andy Polyakov
<appro@fy.chalmers.se> (see http://fy.chalmers.se/~appro/mkisofs_plus.html)


Any comments, bug reports/fixes to the address below

James Pearson (j.pearson@ge.ucl.ac.uk)
18/5/98