The hard disk main guides record the main boot record of the hard disk records 0 head 0 cylindrical 1 sector in the hard disk. The main boot record consists of three parts: (1) main boot program; (2) four partition tables; (3) main boot record valid flag word. See Table 1 for details. Table 1: Main boot record structure location content
0000H-00D9H main guidance recording code area 00dah-01bdh idle area 01beh-01cdh partition 1 Structure information 01CEH-01DDH partition 2 Structure information 01deh-01edh partition 3 Structure information 01eeh-01FDH partition 4 Structure 01FEH-01FFH55AH main boot record effective Sign
The partition is started from the offset 1beh, and the partition table has a total of 64 bytes, and the four partition information can be filled in the table, and each 16 bytes are one partition description, this 16-byte mean is shown in Table 2. It must be noted that the highest bits of the height of the sector number of the sector number, that is, the cylinder is 10 digits, and the sector number is 6 digits. Table 2: Subregional Structure Offset Length Meaning
Offset length meanings 00h1 active partition indicator, the value is 80h is expressed as a self-respecting partition (only one), the value is 00h indicates that the remaining partition 01H1 partition start head number 02H1 low 6 bits are sectors starting in the partition, The high 2 bits are the starting 8-bit 04H1 system flag of the starting column nogrammet started at the beginning of the cylinder starting cylinder, which is 01h, indicating a DOS partition using 12-bit FAT format, which represents 16 Bit FAT format DOS partition, this value is 05h is expressed as an extended DOS partition, which is represented as a DOS system 05H1 partition termination number 06H1 low 6 bits as the sector number ended by the partition, and the head 2 is the first 2 position of the column. The 07h1 partition ends 8 bits of the column number. 08h4 The number of sectors before this partition, the low byte in the first 0ch4, the total number of sectors, the low byte is before
