DOS Boot Record Format for FAT12 and FAT16 |
Offset |
Size |
Field |
Default |
00H |
3 |
Jump |
E9 XX XX or EB XX 90 (Hex) |
03H |
8 |
OEM ID |
MSWIN4.0 |
|
BIOS Parameter Block |
0BH |
2 |
Bytes Per Sector |
512 |
0DH |
1 |
Sectors Per Cluster |
(See Table of Cluster Sizes ) |
0EH |
2 |
Reserved Sectors |
1 |
10H |
1 |
Number of FATs |
2 |
11H |
2 |
Number of Root Directory Entries |
512/544 |
13H |
2 |
Total Sectors in Logical Volume (Small, For Logical Volume Size Less than or Equal to 32 MB) |
0 |
15H |
1 |
Media Descriptor Byte |
(See the Table of Media Descriptors) |
16H |
2 |
Number of Sectors Per FAT |
Must Be Calculated |
|
(End of BIOS Parameter Block) |
18H |
2 |
Sectors Per Track |
Depends on Hard Disk, Usually 63 |
1AH |
2 |
Number of Heads |
Depends on Hard Disk |
1CH |
4 |
Number of Hidden Sectors |
|
20H |
4 |
Total Sectors in Volume (Large, Logical volume size greater than 32MB) |
Size of the partition in terms of Sectors |
|
Extended Boot Record Information (DOS 4.0 and Later) |
24H |
1 |
Physical Drive Number |
80H |
25H |
1 |
Current Head |
0 |
26H |
1 |
Extended Boot Signature Record |
for WinNT, 28H else 29H |
27H |
4 |
Volume Serial Number
(32 – bit Binary Volume ID) |
Random |
2BH |
11 |
Volume Label |
1 |
36H |
8 |
File System ID |
FAT12, FAT16 |
Total |
62 |
|
|
