Question: is the hard disk partition table just the "Partition Table"? Is it made up of three parts: the boot sector, the file allocation table (FAT), and the master boot record (MBR)?
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中国DOS联盟论坛 » DOS学习入门 & 精彩文章 （教学室） » Newbie question about the hard disk partition table, please advise.
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Posted 2004-01-04 00:00 · 中国 云南 昆明 联通
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Posted 2004-01-04 00:00 · 中国 辽宁 抚顺 联通
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Detailed explanation of the hard disk partition table:
Hard disk master boot sector = hard disk master boot record (MBR) + hard disk partition table (DPT)
--------------------------------------------------------------
Physical location: side 0, track 0, sector 1 (clindyer 0, side 0, sector 1)
Size: 512 bytes
Among them: MBR 446 bytes (0000--01BD), DPT 64 bytes (01BE--01FD), end marker 2 bytes (55 AA)
Function: the MBR checks the DPT partition information and guides the system to jump to the DBR;
Read: use NORTON DISKEDIT, choose DRIVE——>PHYSICAL DISK-—HARD DISK in the OBJECT menu,
then choose DISK PARTITION TABLE in the OBJECT menu to read it, and use the WRITE OBJECT TO option in the TOOLS menu to save it to the specified file for backup;
Write: use NORTON DISKEDIT, choose DRIVE——>FLOOPY DISK in the OBJECT menu, select the backed-up DPT
file, then use the WRITE OBJECT TO——>PHYSICAL SECTOR option in the TOOLS menu to write to 001
(clindyer 0, side 0, sector 1);
Detailed explanation:
000H--08AH MBR boot program (looks for the boot partition)
08BH--0D9H MBR boot string
0DAH--1BCH Reserved ("0"
1BEH--1FDH Hard disk partition table
1FEH--1FFH End marker (55AA)
Active partition master boot sector (DBR)
--------------------------
Physical location: side 1, track 0, sector 1 (clindyer 0, side 1, sector 1)
Size: FAT16 1 sector 512 bytes
FAT32 3 sectors 1536 bytes
Function: contains machine CMOS and other information (0000--0059), checks this information and boots the specified system files, such as NTLDR, etc.;
Read: use NORTON DISKEDIT, choose DRIVE——>LOGICAL DISK-—DISK C in the OBJECT menu,
then choose BOOT RECORD in the OBJECT menu to read it, and use the
WRITE OBJECT TO option in the TOOLS menu to save it to the specified file for backup;
Write: use NORTON DISKEDIT, choose DRIVE——>FLOOPY DISK in the OBJECT menu, select the backed-up DBR
file, then use the WRITE OBJECT TO——>PHYSICAL SECTOR option in the TOOLS menu to write to 011
(clindyer 0, side 1, sector 1);
Detailed explanation:
000H--002H 3-byte jump instruction (goes to the boot program, jumps to 03EH)
003H--03DH BIOS parameter area
03EH--19DH DOS boot program
19EH--1E5H Boot string
1E6H--1FDH Filenames (IO.SYS, MSDOS.SYS)
1FEH--1FFH End marker (55AA)
Hard disk partition table (DPT)
---------------------
Offset address Byte count Meaning analysis
01BE 1 Partition type: 00 means non-active partition; 80 means active partition; others are invalid partitions.
01BF~01C1 3 *Starting address of the partition (side/sector/track). Usually the starting address of the first partition begins
at side 1, track 0, sector 1, so these three bytes should be 010100
01C2 1 #Type of operating system for the partition.
01C3~01C5 3 *Ending address of the partition (side/sector/track)
01C6~01C9 4 Starting logical sector of the partition
01CA~01CD 4 Total number of sectors occupied by the partition
Note: * Pay attention to the byte allocation in the starting address (side/sector/track) and ending address (side/sector/track) of the partition:
00000000 01000001 00010101
~~~~~~~~ ==^^^^^^ ========
~ Side (head) 8 bits
^ Sector 6 bits
= Track 10 bits
# Partition operating system type (file format flag code)
4---DOS FAT1632M
7---NTFS(OS/2)
83---LINUX>64M
The DPT is 64 bytes in total (01BE--01FD). As shown above, each partition occupies 16 bytes, so it can represent four partitions. This
is why the total number of primary partitions and extended partitions on one disk can only be four.
Logical drives
-----------
The information for the extended partition is located in the hard disk partition table (DPT) shown above, while the information for logical drives is located in the
starting sector of the extended partition, that is, the sector corresponding to the starting address of that partition (side/sector/track). The difference between the information in this sector and the hard disk master boot
sector is that it does not contain an MBR, and the 16-byte partition information represents the starting and ending addresses of the logical drive, etc.
Hard disk master boot sector = hard disk master boot record (MBR) + hard disk partition table (DPT)
--------------------------------------------------------------
Physical location: side 0, track 0, sector 1 (clindyer 0, side 0, sector 1)
Size: 512 bytes
Among them: MBR 446 bytes (0000--01BD), DPT 64 bytes (01BE--01FD), end marker 2 bytes (55 AA)
Function: the MBR checks the DPT partition information and guides the system to jump to the DBR;
Read: use NORTON DISKEDIT, choose DRIVE——>PHYSICAL DISK-—HARD DISK in the OBJECT menu,
then choose DISK PARTITION TABLE in the OBJECT menu to read it, and use the WRITE OBJECT TO option in the TOOLS menu to save it to the specified file for backup;
Write: use NORTON DISKEDIT, choose DRIVE——>FLOOPY DISK in the OBJECT menu, select the backed-up DPT
file, then use the WRITE OBJECT TO——>PHYSICAL SECTOR option in the TOOLS menu to write to 001
(clindyer 0, side 0, sector 1);
Detailed explanation:
000H--08AH MBR boot program (looks for the boot partition)
08BH--0D9H MBR boot string
0DAH--1BCH Reserved ("0"
1BEH--1FDH Hard disk partition table
1FEH--1FFH End marker (55AA)
Active partition master boot sector (DBR)
--------------------------
Physical location: side 1, track 0, sector 1 (clindyer 0, side 1, sector 1)
Size: FAT16 1 sector 512 bytes
FAT32 3 sectors 1536 bytes
Function: contains machine CMOS and other information (0000--0059), checks this information and boots the specified system files, such as NTLDR, etc.;
Read: use NORTON DISKEDIT, choose DRIVE——>LOGICAL DISK-—DISK C in the OBJECT menu,
then choose BOOT RECORD in the OBJECT menu to read it, and use the
WRITE OBJECT TO option in the TOOLS menu to save it to the specified file for backup;
Write: use NORTON DISKEDIT, choose DRIVE——>FLOOPY DISK in the OBJECT menu, select the backed-up DBR
file, then use the WRITE OBJECT TO——>PHYSICAL SECTOR option in the TOOLS menu to write to 011
(clindyer 0, side 1, sector 1);
Detailed explanation:
000H--002H 3-byte jump instruction (goes to the boot program, jumps to 03EH)
003H--03DH BIOS parameter area
03EH--19DH DOS boot program
19EH--1E5H Boot string
1E6H--1FDH Filenames (IO.SYS, MSDOS.SYS)
1FEH--1FFH End marker (55AA)
Hard disk partition table (DPT)
---------------------
Offset address Byte count Meaning analysis
01BE 1 Partition type: 00 means non-active partition; 80 means active partition; others are invalid partitions.
01BF~01C1 3 *Starting address of the partition (side/sector/track). Usually the starting address of the first partition begins
at side 1, track 0, sector 1, so these three bytes should be 010100
01C2 1 #Type of operating system for the partition.
01C3~01C5 3 *Ending address of the partition (side/sector/track)
01C6~01C9 4 Starting logical sector of the partition
01CA~01CD 4 Total number of sectors occupied by the partition
Note: * Pay attention to the byte allocation in the starting address (side/sector/track) and ending address (side/sector/track) of the partition:
00000000 01000001 00010101
~~~~~~~~ ==^^^^^^ ========
~ Side (head) 8 bits
^ Sector 6 bits
= Track 10 bits
# Partition operating system type (file format flag code)
4---DOS FAT1632M
7---NTFS(OS/2)
83---LINUX>64M
The DPT is 64 bytes in total (01BE--01FD). As shown above, each partition occupies 16 bytes, so it can represent four partitions. This
is why the total number of primary partitions and extended partitions on one disk can only be four.
Logical drives
-----------
The information for the extended partition is located in the hard disk partition table (DPT) shown above, while the information for logical drives is located in the
starting sector of the extended partition, that is, the sector corresponding to the starting address of that partition (side/sector/track). The difference between the information in this sector and the hard disk master boot
sector is that it does not contain an MBR, and the 16-byte partition information represents the starting and ending addresses of the logical drive, etc.
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Posted 2004-01-05 00:00 · 中国 天津 电信
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Aha!!!! I See!!
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Posted 2004-01-06 00:00 · 中国 云南 昆明 联通
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Many thanks
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Posted 2004-01-11 00:00 · 中国 广东 惠州 鹏博士宽带
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Why can't I understand this? Is there something for beginners to read?
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