Hard Disk Geometry
Last updated
Computer Systems Forensic Analysis
Last updated
Low-level format.
to create data structures.
tracks - addresses start from outside.
cylinders - all tracks at a given address on all platters C ∈ [0, maxC ].
tracks can be addressed by the head number H ∈ [0, maxH ]
sectors - subdivision of tracks, typically 512 bytes S ∈ [1, maxS ]
Get one sector CHS.
Cylinder address (C).
Head number (H).
Sector address (S).
Cylinder, Head, Sector (CHS) – used only on older systems.
maximum addressable capacity 504 MB.
way around the problem with fake geometry.
but this translation was limited to address a maximum of 8,1 GB.
Logical Block Address (LBA).
each sector has a unique address.
the software doesn’t need to know the disk geometry.
LBA/CHS conversion:
LBA = (C × maxH + H) × maxS + (S − 1)
