CS2650
FAT16 Disk Decoder
Boot Sector extended BIOS parameter block
| Offset in Boot Sector | Length in Bytes | Description |
| 0BH | 2 | Number of Bytes per Sector |
| 0DH | 1 | Number of sectors per cluster |
| 0EH | 2 | Number sectors in reserved area |
| 10H | 1 | Number of copies in FAT |
| 11H | 2 | Number of root directory entries |
| 13H | 2 | Total number of Sectors (if less than 65536) |
| 15H | 1 | MS-DOS media descriptor |
| 16H | 2 | Number of Sectors per FAT |
| 18H | 2 | Number of sectors per Track |
| 1AH | 2 | Number of Heads (Sides) |
| 1CH | 4 | Number of hidden sectors |
| 20H | 4 | Total number of Sectors (if greater than 65535) |
| 24H | 1 | Physical Drive Number |
| 25H | 1 | Reserved |
| 26H | 1 | Signature Byte |
| 27H | 4 | Volume Serial Number |
| 2BH | 11 | Volume Label |
| 36H | 8 | File System Type |
Directory Entries
| Offset | Description | Size | Format |
| 00H | Filename | 8 | ASCII Characters |
| 08H | Filename extension | 3 | ASCII Characters |
| 0BH | Attribute | 1 | Bit Coded*** |
| 0CH | Reserved | 10 | Unused |
| 16H | Time | 2 | Coded** |
| 18H | Date | 2 | Coded* |
| 1AH | Starting Cluster Number | 2 | Integer |
| 1CH | File Size | 4 | Integer |
*Date: Year = Left 7 bits (+1980), Month = Middle 4 bits, Day = Right 5 bits
**Time: Hour = Left 5 bits, Minutes = Middle 6 bits, Seconds = Right 5 bits (x2)
***Attribute
bit 0 = Read-Only
bit 1 = Hidden
bit 2 = System
bit 3 = Volume Label
bit 4 = Subdirectory
bit 5 = Archive