Shulou(Shulou.com)06/03 Report--

one。 Operating system

a. From this we can get a question, what is the operating system?

1. Windows,UNIX,Linux,Mas OS,Android,ios is a common operating system in our daily life.

two。 An operating system is a computer program that runs directly on hardware.

3. The operating system is used to manage and control computer hardware and software resources.

4. The operating system provides necessary services and interfaces for the development of user software.

b. Modern computer system architecture

BIOS-Base Inout&Output System (it should be noted that BIOS is not software, but firmware, which is a program solidified in hardware that has been burned and fixed before the hardware leaves the factory)

1.BIOS is the first program to run after the computer is powered on.

2.BIOS first checks the hardware status, and initializes the hardware immediately after passing the test.

3.BIOS builds interrupt vector tables in memory (provides a way to access hardware)

4.BIOS finally hands over control to the master bootstrapper.

System Startup process (X86)

The operating Mechanism of BIOS

1.BIOS is stored in ROM, and the address is mapped to 0xF0000-0xFFFFF (real address)

The entrance address of 2.BIOS is: 0xFFFF0

3. The special design of the hardware circuit causes the CPU to be executed from the 0xFFFF0 after boot.

The final mission of BIOS

1. Scan each storage media (CD drive, floppy drive, USB disk, etc.) according to user settings

two。 When the master boot area is found, load the master boot program in the master boot area into memory

3. The entry address of the master bootstrapper in memory is 0x7c00

4. Transfer control to the main program to execute (jmp 0x7c00)

How does Q:BIOS find the primary boot area in the storage media? How to determine if there is a master bootstrap in the boot area?

Main guidance area (MBR:Master Boot Record)

Location: at the beginning of the storage media, with a size of 512 bytes

Features: the last 2 significant bytes of the first 512 bytes are 0x55aa

Data: data prior to 0x55aa is treated as the master bootstrap

Improved system startup process

Summary

1.BIOS is the first program to run after the computer is powered on.

2.BIOS performs the necessary initialization and loads and runs the main bootstrap program

3. The master bootstrap is located at the first 512 bytes of the storage media

4. The master bootstrap is responsible for subsequent initialization and loading and running the operating system kernel

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