Buffer Layout for DOS3+
10h bytes control info per disk buffer, followed by 512-byte buffer
00h DWORD Pointer to next disk buffer, FFFFh if last
04h BYTE Drive (0=A:)
05h BYTE Flags
| Flags |
| Bit |
Dec |
Hex |
Description |
| 0 |
1 |
01h |
??? |
| 1 |
2 |
02h |
Sector in FAT |
| 2 |
4 |
04h |
Sector in Root
Directory |
| 3 |
8 |
08h |
Sector in Data area |
| 4 |
16 |
10h |
??? |
| 5 |
32 |
20h |
May be overwritten
(buffer is not dirty) |
| 6 |
64 |
40h |
??? |
| 7 |
128 |
80h |
??? |
06h WORD Logical sector number
08h 2 BYTEs ???
0Ah DWORD Pointer to DOS Device Control Block
0Eh WORD Unused??? (almost always 0) |