Symantec GHOST IMAGING FOUNDATION 7.1, Manual

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Table A-3
Completeness of coverage (continued)
Description Control
There may be storage on the disk that is not directly addressable
by GDisk. GDisk does not support the following features:
■
Bad sector remapping
The disk may have spare sectors available that are used to
automatically remap, or substitute, bad sectors by the disk
firmware. This is a potential security risk, for example, if a bad
sector may have been remapped and the original location on
the disk platter previously used by that sector becomes
inaccessible. However, it is possible that the bad sector may
still contain readable data that could be accessed by a skilled
hard-drive engineer.
■
Host Protected Area (HPA)
If the HPA is password protected, then this area of the disk is
not addressable by GDisk.
■
Inaccurate disk geometry detection
An error in determining the disk size could result in
non-accessibility.
■
Specialized disk commands
Specialized disk commands, such as those used to access
SMART logs, indicate that a disk may store data that is not
accessible using standard commands.
■
Wiping of locked sectors
The operating system may lock some of the sectors on the disk.
These sectors cannot be accessed by GDisk and are not wiped.
This is more likely to happen when you run GDisk in Windows
than in DOS. GDisk gives notification of which sectors were
not overwritten.
Non-addressable
locations
Determining disk size
The BIOS function calls, or disk commands, used for determining the size of the
disk are as follows:
■
Int13h, Get Drive Parameters (08h)
■
Extended Int13h, Get Drive Parameters (48h)
■
Direct IDE, IDENTIFY DEVICE(ECh)
■
Direct SCSI, READ CAPACITY (25h)
129 GDisk disk-wipe specifications
Determining disk size