以下资料仅供参考:
----------------------------------------------------------------------------------------
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*
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
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
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
----------------------------------------------------------------------------------------
<End>
