DSK_SETDEVICEPARAMS (43h) - Extended BPB for Devices

Extended BPB for Devices

The term Extended BPB refers to the BIOS Parameter Block. It is a table that describes the structure of the media and the physical layout of the drive (heads, tracks, sectors).

The Extended BPB has the following format:

┌─────────────────────────┬───────┐
│Field                    │Length │
├─────────────────────────┼───────┤
│Bytes per Sector         │WORD   │
├─────────────────────────┼───────┤
│Sectors per Cluster      │BYTE   │
├─────────────────────────┼───────┤
│Reserved Sectors         │WORD   │
├─────────────────────────┼───────┤
│Number of FATs           │BYTE   │
├─────────────────────────┼───────┤
│Root Directory Entries   │WORD   │
├─────────────────────────┼───────┤
│Total Sectors            │WORD   │
├─────────────────────────┼───────┤
│Media Descriptor         │BYTE   │
├─────────────────────────┼───────┤
│Sectors per FAT          │WORD   │
├─────────────────────────┼───────┤
│Sectors per Track        │WORD   │
├─────────────────────────┼───────┤
│Number of Heads          │WORD   │
├─────────────────────────┼───────┤
│Hidden Sectors           │DWORD  │
├─────────────────────────┼───────┤
│Large Total Sectors      │DWORD  │
├─────────────────────────┼───────┤
│Reserved                 │6 BYTES│
└─────────────────────────┴───────┘

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