POST self test order, POST self test order

Plug in the microcomputer and the system will perform a routine of self-checking. This is part of the BIOS feature and is often referred to as the Power on Self Test.

The complete POST self-test includes testing of the CPU, system motherboard, basic 640KB memory, more than 1MB of extended memory, and system ROM BIOS; Validation of system configuration in CMOS; Initialize the controller, test the memory, check signal and synchronization signal, and test the CRT interface; Check keyboards, floppy drives, hard disks and CD ROM subsystems; Check the parallel port (printer) and serial port (RS232). If there is an error found in the self-test, it will be handled according to two situations: for serious faults (fatal faults), the machine will be stopped, and no prompts or signals can be given because various initialization operations have not been completed; For non-serious faults, a prompt or audible alarm signal will be given, waiting for the user to deal with it.

The POST self-test process is roughly as follows: power on the CPU ROM BIOS system

clock－dma－64kb

RAM IRQ graphics card, etc., that is, CPU - memory - graphics card - hard disk.

When the computer is turned on, the first thing to do is POST (power-on self-test), that is, to check whether the key equipment such as system memory and graphics card are plugged in and can work normally; Next, check the BIOS initialization information of the graphics card, which is the information of the graphics card displayed on the screen that we often see, such as the manufacturer, graphics chip type, and video memory capacity. Next, the screen displays the splash screen, which includes the type of BIOS system, serial number, version number, BIOS date, motherboard chipset model and manufacturer**, etc. Next, check the CPU type, working frequency, memory capacity and other information; Next, detect and configure hardware devices, including plug-and-play devices such as hard drives, optical drives, keyboards, and mice. Then, the screen displays the system configuration table, including various standard hardware devices and related working parameters; Then boot the system according to the boot sequence set by the user, and the boot sequence from the floppy disk, hard disk or optical drive set by the user in the BIOS; Finally, enter the Windows desktop and boot the computer successfully.

The POST self-test process is roughly as follows: powering up the CPU ROM BIOS System Clock DMA 64KB RAM IRQ graphics card, etc., that is, CPU - MEMORY - GRAPHICS CARD - HARD DISK.

The self-test order is CPU - Memory - Graphics Card - Hard Disk.

Boot POST self-test can't pass,Mainly the graphics card---CPU--- memory these three,Of course, the platform with these three things,That is, the motherboard can't pass if there is a problem.,There is also a power supply。

As for the hard disk, it is irrelevant, because it can be booted without the hard disk (it is not excluded that the fatal error of the hard disk will affect the boot).

Unless you turn off the power, the computer won't self-test.

Power-up CPU ROM BIOS System Clock DMA 64KB RAM IRQ graphics card, etc. The previous process of detecting the graphics card is called the key component test, the BIOS is not to detect the three seats of the computer, he has to detect the network card on the computer, the sound card, the CPU graphics card, and the first detection** depends on the BIOS settings.

The POST self-test process is roughly as follows: powering up the CPU, ROM, BIOS, System Clock, DMA, 64KB, RAM, IRQ, graphics card, etc. The process before detecting a graphics card is called critical component testing, and if there is a problem with a critical component, the computer is left in a suspended state, which is customarily called a core failure.

After the graphics card is detected, the computer will detect more than 64KB of memory, IO ports, soft hard disk drives, keyboards, plug-and-play devices, CMOS settings, etc., and display various information and error reports on the screen. Under normal circumstances, the POST process goes so fast that we can barely feel it.

1.Power on button The motherboard controller sends a reset signal to the CPU for CPU initialization.

2.When the power supply is stable, the chipset removes the RESET signal, and the CPU immediately starts executing instructions from FFFFOH to enter the BIOS.

3.The first thing to do when the system BIOS is booted** is to perform a POST (Power Up Self-Test).

4.Displays the version of the ROM-BIOS, copyright information, and the detected CPU model, clock speed, and memory capacity. During this process, the self-test program also tests the bytes of the DAM (Memory) controller and the ROM-BIOS chip.

Continue to check and initialize devices such as interrupt controllers, timers, keyboards, extended IO interfaces, IDE interfaces, and floppy drives. Prior to this, the machine has been judging whether the user has pressed the "DEL" key, and if so, it will enter the system setup program in the ROM-BIOS, save the configuration of the system (such as soft and hard disk models) in the form of parameters into the CMOS RAM, and then restart. ）

5.The self-test program will identify some of the system's hardware settings based on what is in the CMOS RAM and initialize these parts.

6.Start reading data from the hard disk, boot the operating system.