Excerpted from CHINAUNIX.NET Sender: Nightowl (OWLET), Write Region: Linux Title: Main Boot Sector Doubt Send Station: BBS Shuimu Tsinghua Station (SAT NOV 20 06:50:43 1999) Main guidance sector : Guide sectors, main guides, main boot records, hard disk partition tables. Nightowl 1999.11 ------------------------------------------------ ------------------- This article is not complete, if you have good comments and suggestions, please contact me. --------------- -------------------------------------------------- - Many friends are not very clear about the difference between MBR (Main Boot Record) and DPT (Disk Partition Table) in the main boot sector of the hard disk. So I want to write it a short introduction, I hope to help these friends a bit helpful. The boot sector exists in each partition, but we often say * main guiding sectors * is the first physical sector of the hard disk. It consists of two parts: the main boot record MBR and hard disk partition table DPT. In the total 512-byte main guidance partition, MBR accounts for 446 bytes (offset 0 - offset 1bdh), DPT accounts for 64 bytes (offset 1beh - offset 1FDH), last two bytes "55, AA" (offset 1FEH offset 1ffh) is the end flag of the partition. The general structure is as follows: 0000 | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ------ | | | | | |Main boot record | | | | | | Main boot record (446 bytes) | | | | | | 01BD | | 01BE | ------ --------------------------------------- | | | 01CD | Partition information 1 (16 words Festival) | 01CE | --------------------------------------------- --- | | | 01DD | Partition Information 2 (16 bytes) | 01de | ------------------------------- ----------------- | | | 01ed | Partition information 3 (16 bytes) | 01ee | ----------------- ------------------------------- | | | 01FD | Partition information 4 (16 bytes) | | ---- -------------------------------------------- | | 01FE | 01FF | | 55 | aa | | -------------------------------------------- ---- | Figure 1: The main boot sector structure map main boot record contains a series of parameters and a boot program for the hard disk. The boot procedure is mainly used to guide the operating system on the partition of the activation flag after the system hardware self-test. It performs a JMP command to jump to the boot program of the operating system. It is often an injection point of guided pathois, and is also an injection point of various multi-system boot procedures. However, since the bootstrap itself is relatively simple, we can completely determine the legality of the bootstrap (see the legality of the JMP instruction), and is also easy to repair. The image command fdisk / MBR can fix the MBR and KV300 software to kill any type of boot virus, which is this reason. The next is the partition table of the hard disk, consists of 4 16-byte partition information tables.
