Symantec GHOST IMAGING FOUNDATION 7.1, Manual

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Table A-2
GDisk clearing, sanitizing or viewing operations (continued)
Description Operation
GDisk performs a sanitize operation, as defined by action d, when
performing a disk-wipe operation with the /diskwipe /dodwipe
command modifier.
The following cycle occurs six times:
■
All addressable locations are overwritten with 0x35.
■
All addressable locations are overwritten with 0xCA.
■
All addressable locations are overwritten with a
pseudo-random character.
■
All addressable locations are verified in hardware using the
Verify Sectors command to the disk.
Sanitizing a disk
You can use GDisk to view the overwrite pattern on the disk to
confirm the overwrite has occurred. This lets you display one or
more sectors to the screen, starting at sector n, of a physical disk
(by default, 1 sector is displayed). Viewing a disk
About completeness of coverage
Table A-3 details the control that GDisk has over the disk and, therefore, the
completeness of the wipe.
Table A-3
Completeness of coverage
Description Control
The smallest addressable unit on a hard disk is the sector. The
sector comprises 512 bytes in IDE drives but may have larger
numbers of bytes in SCSI or ATAPI disks.
The NISPOM assumes that the smallest addressable location is
the size of a character, presumably an 8-bit character, which
occupies 1 byte of storage.
GDisk assumes that the smallest addressable location on the disk
is a byte. Byte addressing is achieved by constructing a block of
data, one or more sectors in size with the chosen character filling
each byte in the block, and writing that block to the disk.
Addressable locations
127 GDisk disk-wipe specifications
About completeness of coverage