BOOT，FAT16结构的详细介绍
以下资料仅供参考:
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目录项(Directory Entries)
文件属性字节(File attribute byte)
FAT16结构(FAT16 structure)
磁盘引导记录结构(BOOT record layout)
目录项(Directory Entries)
|
offset |
length |
description |
format |
comments |
|
00H |
8 bytes |
filename |
ASCII chars,or special code if first char: 00H=name never used 05H=first character or name is realy E5H E5H=file was used,but has been erased 2EH=entry is a directory |
must be padded with spaces to fill field |
|
08H |
3 bytes |
file type(extension) |
ASCII chars |
must be padded with spaces to fill field |
|
0BH |
byte |
file attribute |
bit codes: bit0=read-only bit1=hidden bit2=system bit3=volumn label bit4=directory bit5=archive bit6=unused bit7=unused |
|
|
0CH |
10 bytes |
reserved |
||
|
16H |
word |
time file last updated |
coded word:(unsigned 16 bit-bit integer) time=Hr*2048+Min*32+Sec+2 |
*:least significant byte first |
|
18H |
word |
date file last updated |
coded word:(unsigned 16 bit-bit integer) time=(Yr-1980)*512+Mon*32+Day |
*:least significant byte first |
|
1AH |
word |
starting cluster number |
word binary integer* |
|
|
1CH |
dbl word |
file size |
double word binary integer* |
目录项(Directory Entries)
文件属性字节(File attribute byte)
FAT16结构(FAT16 structure)
磁盘引导记录结构(BOOT record layout)
文件属性字节(File attribute byte)
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | meaning if set to 1 | meaning if set to 0 |
| v | read-only file | read/write file | |||||||
| v | hidden file | visible file | |||||||
| v | system file | regular file | |||||||
| v | volumn name | regular file | |||||||
| v | directory name | regular file | |||||||
| v | file changed since last backup | file unchanged since last backup | |||||||
| v | v | reserved | reserved |
目录项(Directory Entries)
文件属性字节(File attribute byte)
FAT16结构(FAT16 structure)
磁盘引导记录结构(BOOT record layout)
FAT16结构(FAT16 structure):
|
Entry |
Example Value |
Use |
|
0 |
FFF8 |
Disk ID byte |
|
1 |
FFFF |
Filler |
|
2 |
0003 |
Cluster value: 0000 = unused cluster 0002-ffff= next cluster number fff0-fff6= reserved cluster fff7 = cluster marked bad fff8-ffff= last cluster in file |
|
3 |
0004 |
|
|
4 |
0005 |
|
|
5 |
FFFF |
|
|
6 |
0000 |
目录项(Directory Entries)
文件属性字节(File attribute byte)
FAT16结构(FAT16 structure)
磁盘引导记录结构(BOOT record layout)
磁盘引导记录结构(BOOT record layout)
dos3.3 and dos4.0 BOOT record layout
| offset | length | description | DOS version |
| 00 | 3 bytes | JMP to boot code | |
| 03 | 8 bytes | OEM name and version | |
| 0B | word | bytes per sector | |
| 0D | byte | sectors per cluster(must be a power of 2) | |
| 0E | word | reserved sectors(for Dir,FAT,etc.) | |
| 10 | byte | Number of copies of FAT | |
| 11 | word | Maximum number of root directory entries | |
| 13 | word | Total number of sectors in logical image | |
| 15 | byte | Media descriptor byte | |
| 16 | word | number of sectors in FAT | |
| 18 | word | number of sectors per track | |
| 1A | word | number of heads | |
| 1C | word | number of hidden sectors | |
| 1E | word | HO number of hidden sectors | |
| 20 | dbl word | number of logical sectors |
DOS5.0 BOOT sector structrure
|
offset |
length |
description |
DOS version |
|
1E |
dbl word |
number of hidden sectors |
DOS 5.0 boot sector structure |
|
22 |
dbl word |
number of sectors if the size of the drive is larger than 32MB |
|
|
23 |
byte |
drive number used Internally by DOS |
|
|
24 |
byte |
reserved |
|
|
25 |
byte |
boot signature. always 29H. |
|
|
29 |
dbl word |
volumn ID number |
|
|
34 |
11 bytes |
Volumn label |
|
|
3C |
8 bytes |
file-system type |
目录项(Directory Entries)
文件属性字节(File attribute byte)
FAT16结构(FAT16 structure)
磁盘引导记录结构(BOOT record layout)
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