Platter (Each platter has two surfaces which store multiple physical units of data)
Tracks (Each disk has many tracks that store multiple physical units of data)
Sectors (Each track has many sectors that each hold a single physical unit of data)
- Sectors used to be 512B, but all modern disks use 4KB sectors due to aerial density issues

SSD Physical Storage Areas

Logical Storage Areas

Allocation Unit (Combinations of sectors that hold a single logical unit of data as understood by the File System)
- Known as Clusters in MS-DOS FAT and NTFS
- Known as Blocks in Linux File Systems
Pages
- They are groups of allocation units by which an OS reads or writes in one go

Cluster (Windows) / Block (Linux) / Allocation Unit (Neutral)
Track (Radial Divisions) (Also called a segment, but bad terminology)
Sector (Circumferential Divisions)
- Disc Sector (The whole sector)
- Track Sector (The sector of a track) (Allocation Units / Blocks / Clusters)
Sectors per Track (differs per track, the middle tracks have fewer sectors to store the same data)
Cylinder (Same track in all platters)

Logical Block Address (LBA)
- LBA = (Cylinder × Max. Heads per Cylinder + Head) × Max. Sectors per Track + (Sector − 1)
Logical Sector sizes can vary due to skew/interleave
Logical Sectors can be smaller than Physical Sectors
- This is often done to support software than assumes old 512B sectors on modern 4K sector discs
- But it causes problems, because to write a 512B sector, it reads 4KB, modifies the relevant part and writes it
- Modern caching techniques may solve this problem

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