Afree’s web site: http://www.afreey.com/afreey.html . I would think that a 40X CD-ROM would be be able to boot. It looks like the CD boot capability is mainly in the motherboard BIOS… Excerpts from the "El Torito" specification (http://www.phoenix.com/products/specs-cdrom.pdf):
An Initial Program Load Device is any device in the system that can boot and load an
O/S. In standard AT machines, this is the floppy drive or hard drive.
An IPL device can be virtually any device that has the ability to load and execute an
O/S. This includes floppy drives, hard drives, CD-ROM drives…
The BIOS Boot Specification defines a feature within the BIOS that creates and
maintains a list of all the IPL devices found in the system and stores this list in NV
memory. IPL devices come in three flavors: BAID, PnP Card, and Legacy. Only
BAIDs and PnP Cards are enumerated. Legacy devices are not supported…
The BIOS Boot Specification provides one basic feature, the IPL Priority. The IPL
Priority is a user-specified priority of IPL devices that is arranged in Setup. This boot
order is similar to the common feature of boot A: then C: or vice versa, but supports
additional IPL devices.
If an IPL device fails to load an O/S, the BIOS regains control and attempts to boot
from the next available IPL device. This procedure will continue until all possible IPL
devices have been exhausted. Only then will the BIOS display a message that an O/S
cannot be found, wait for a key stroke, and then invoke INT 19h again. This method
ensures that the BIOS has intelligently made every attempt to boot.
A BIOS Aware IPL Device is any device that can boot an O/S, but requires the BIOS
to have specific code to support it. Some examples are: the first floppy drive, the first
hard drive, ATAPI CD-ROM…
Note that only the first floppy drive and the first hard drive are considered IPL devices.
The main reason why a system cannot boot from other drives is that the boot sector
code specifically addresses only these drives (00h for floppy and 80h for hard drive)
when INT 13h is called to load the O/S….
Option ROMs are detected during the BIOS’ scan and their initialization vectors are
called. During initialization, devices may hook INT 19h so that they will gain control
when the BIOS issues INT 19h to boot the system. Or, they may hook INT 18h so that
if all other IPL devices in the system fail to boot they will take over. Or, they may
simply hook INT 13h and only respond to calls that reference their drive number. In
any case, the first two methods provide no consistent way for the BIOS to regain
control if the device fails to boot.
Boot Menu Pop-up
Another way to view the IPL Priority is to use a Boot Menu that pops up during
POST. If you press <Hot-Key> during POST, the Boot Menu will appear just before
the BIOS issues INT 19h. The Boot Menu won’t appear unless <Hot-Key> is pressed
As in Setup, the Boot Menu displays all the IPL devices in the order they will be
selected for booting. However, unlike in Setup, the Boot Menu doesn’t allow you to
edit the position of an IPL device in the IPL Priority. This menu simply allows you to
select a Boot First device. A Boot First device attempts booting first before the regular
IPL Priority is considered. You select a Boot First device from the Boot Menu by
using the up/down arrow keys to move the highlight bar to the desired device, and then
by pressing <Enter> the ordinal value from the IPL Priority for this selection is stored
so that later the INT 19h handler can boot from this device. If you press <Hot-Key>
while the Boot Menu is up, the Boot Menu exits without saving a selection.”