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48 lines
1.1 KiB
Plaintext
48 lines
1.1 KiB
Plaintext
=== Geometry Block (`GEOM`)
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The geometry block encapsulates metadata that defines the disk’s geometry, primarily to support transformations between CHS (Cylinder-Head-Sector) and LBA (Logical Block Addressing) addressing schemes.
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Note that the stored geometry may not reflect the media’s actual physical layout.
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Instead, it typically represents the translation parameters active at the time the drive image was acquired.
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[source,c]
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#define GEOM_MAGIC 0x4D4F4547
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/**Geometry block, contains physical geometry information */
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typedef struct GeometryBlockHeader
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{
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/**Identifier, <see cref="BlockType.GeometryBlock" /> */
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uint32_t identifier;
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uint32_t cylinders;
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uint32_t heads;
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uint32_t sectorsPerTrack;
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} GeometryBlockHeader;
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==== Field Descriptions
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[cols="2,2,2,6",options="header"]
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|===
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|Type
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|Size
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|Name
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|Description
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|uint32_t
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|4 bytes
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|identifier
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|The geometry table identifier, always `GEOM`
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|uint32_t
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|4 bytes
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|cylinders
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|The number of cylinders.
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|uint32_t
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|4 bytes
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|heads
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|The number of heads.
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|uint32_t
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|4 bytes
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|sectorsPerTrack
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|The number of sectors per track.
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|=== |