User manual

Bootable Disc
Nero Burning ROM 41
9 Bootable Disc
Using Nero Burning ROM you can create a bootable disc with which the computer can be
started without having to access the hard drive. For this reason a bootable disc is often used
as an "emergency disc" to start the computer if it is not possible to access the hard drive.
Bootable discs are created in accordance with the "El Torito" standard, an extension to the
ISO-9660 standard which defines the structure of data discs. The disc contains a boot image
and an ISO part. The boot image contains all files that are required to load the operating
system and to start the computer. The ISO part can contain any number of data files that you
can back up using this method.
9.1 Booting Requirements
To ensure that a computer can boot from disc, the start sequence must be set in the BIOS of
the computer in such a way that the drive is addressed first as the boot drive (start sequence
CD-ROM, C, A for instance). In the case of a SCSI CD-ROM drive, this must be connected
to a SCSI adapter with a separate BIOS whose settings can be modified accordingly. (This
will only work when there are no IDE hard drives present, as these precede the SCSI
adapter in the boot sequence).
When booting from a disc, you can only start an operating system that does not write to the
medium, such as "MS DOS" or "Linux". During booting Microsoft
®
Windows
®
2000 and
Microsoft
®
Windows
®
XP write to the medium from which they are being booted. This is not
possible with a disc and so the process is canceled and the PC cannot be started.
9.2 Bootable Disc Template
For Nero Burning ROM, the template for creating a bootable disc can be either a logical drive
(e.g. the C: drive) or a drive image file which contains the contents of a drive as a file sector
for sector. If the template for the bootable disc is a logical drive, the bootable disc will
emulate this when the system is booting. There are three emulation types:

Floppy emulation: This requires a bootable floppy disc for creating the bootable disc. At
startup the bootable disc emulates a floppy disc in drive A:. In the process, the drive
letters increment, so that Drive A: corresponds to the bootable disc. Floppy drive A: can
be accessed as B: after booting. The volume of the start data is limited by the capacity of
the floppy disk (e.g 1.44 MB).

Hard drive emulation: A bootable hard drive is required to create the bootable disc. At
startup the disc emulates Drive C:. All drive letters from Drive C: increment by one. The
volume of the start data is limited by the capacity of the CD (e.g. 700 MB) or DVD (8.5
GB). If, for instance, you have a 200 GB hard drive with only one (200 GB) partition, you
cannot create a bootable disc from it without repartitioning your hard drive accordingly
beforehand.

No emulation: In this process the drive names are not changed. This type is used for
bootable installation CDs. This setting is intended for users who do not require a floppy or
hard drive emulation and who want to install their own device driver.