Nvidia 4 - Manual (Page 155)

NVIDIA Corporation 151
C HAPTER 7
MediaShield Application Notes
Using GHOST with NVIDIA RAID
Problem
GHOST can interface with hard disk controllers by accessing the appropriate memory and
hardware locations directly. However, in doing so, this can bypass the RAID
enhancements that are provided by the system BIOS. The system BIOS understands the
underlying disk and RAID array structures and formats. In order to properly use GHOST
to interact with a RAID volume, the user should ensure that the tool is operating in a
mode where it does not talk directly to the hardware resources, but rather communicates
using the system BIOS.
Solution
In order to use GHOST in a RAID volume, the user must:
• Disable the GHOST Direct Disk Access
• Force it to rely on Extended INT13 to access the disk
To set GHOST to use Extended Interrupt 13h (INT13) access:
a Start GHOST from the DOS prompt. (Not the Windows Command Prompt session)
b Select the “Options” (ALT+O) menu
c Scroll to the “HDD Access” Tab
d Select the “Use Extended Interrupt 13h disk access” (ALT+E)
e Select the “Disable direct IDE access support” (ALT+B)
f Select the “Disable direct ASPI/SCSI access support” (ALT+B)
g Press (ALT+A) to activate the “Accept” button to use the new settings
h Proceed to run GHOST as normal
These steps will then allow the user to use GHOST to copy the disk image through the
RAID array.
Note: Typically, disk cloning software accelerates data transfer through direct disk access,
which also allows for overlapping read and write calls, further accelerating the
process. Because INT13 calls cannot “overlap”, read and write operations must be
performed in series, which causes the disk cloning process to perform slower when
RAID is enabled.