What is the first thing the computer does to detect the device after it is turned on?

After booting up, the computer first performs a device test called "system self-test". System self-test, also known as "power-on self-test" or "post self-test", refers to the behavior of a computer system that automatically runs the motherboard BIOS chip firmware program when the power is turned on, including testing the CPU, system motherboard, basic memory, extended memory, Testing of system ROM BIOS and other devices. If an error is found during the self-check, it will be handled in two situations: 1. For serious faults (fatal faults), the machine will shut down; 2. For non-serious faults, a prompt or sound alarm signal will be given, waiting for the user to handle.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

After booting up, the computer first performs a device test called "system self-test".

Turn on the power and the computer will first automatically run the motherboard BIOS chip curing program, usually called POST.

Therefore, system self-test is also called "power-on self-test" or "post self-test". It refers to the behavior of the computer system, when the power is turned on, to automatically run the program cured by the motherboard BIOS chip.

Turn on the computer, power on the motherboard and start booting the hardware self-test from the BIOS to the BIOS to select the boot item hard disk or optical drive and look for the boot file. It is called post self-test, critical parts test and non-critical component test. Key component testing, power on, cpu, rom, BIOS, system clock, DMA, 64k RAM, irq, graphics card. If there is a problem, it is called a core failure.

The complete POST self-test includes:

Testing of the CPU, system motherboard, basic 640KB memory, extended memory of more than 1MB, and system ROM BIOS;

• Verification of system configuration in CMOS;

• Initialize the video controller, test the video memory, check the video signal and synchronization signal, and conduct the VGA interface Test;

• Check the keyboard, floppy drive, hard disk and CDROM subsystem; check the parallel port (printer) and serial port (RS232).

If an error is found during the self-test, it will be handled in two situations:

• For serious faults (fatal If there is a serious fault), the machine will stop. At this time, since various initialization operations have not been completed, no prompts or signals can be given;

• For non-serious faults, prompts or sound alarm signals will be given. Waiting for user processing.

After the self-test is completed, the system proceeds to the next step: finding the operating system from the hard disk, CD or network server to start. The control of the computer will be completed by the operating system.

Extended knowledge:

How to cancel the power-on self-test?

Method: Set BIOS

• 1. Press the Del key while booting to enter the advanced BIOS setup page, enter Advanced BIOS Features or BIOS Features Setup

• 2. Find the [Quick Power On SelfTest] item, set it to [Enabled], press F10 to save and exit, and directly press the Esc key to skip the test during future self-tests.

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