A raw disk directly accesses an existing local disk or partition. You can 
use raw disks if you want Workstation to run one or more guest operating 
systems from existing disk partitions. Raw disks may be set up on both IDE 
and SCSI devices. At this time, however, booting from an operating system 
already set up on an existing SCSI disk or partition is experimental.

The most common use of a raw disk is for converting a dual-boot or 
multiple-boot machine so one or more of the existing operating systems can be 
run inside a virtual machine.

Caution: If you run an operating system natively on the host computer, the 
switch to running it inside a virtual machine is like pulling the hard drive 
out of one computer and installing it in a second computer with a different 
motherboard and other hardware. You need to prepare carefully for such a 
switch. The specific steps you need to take depend on the operating system 
you want to use inside the virtual machine. For details, see Configuring a 
Dual-Boot Computer for Use with a Virtual Machine.

You can also create a new virtual machine using a raw disk. For details, see 
Installing an Operating System onto a Raw Partition from a Virtual Machine. 
In most cases, however, it is better to use a virtual disk.

Raw disk configurations are recommended only for expert users.



-- 
Andrew S. Zbikowski | http://www.ringworld.org
"We can learn much more from wise words, little
from wisecracks and less from wise guys."
--William Arthur Ward