009 Embedded Linux-ARM. StorageQueries and discussion related to usage of Linux on ARM based devices. Linux has been ported to a variety of CPUs which are not only primarily used as the processor of a desktop or server computer, but also ARM, AVR32, ETRAX CRIS, FR-V, H8300, IP7000, m68k, MIPS, mn10300, SuperH, and Xtensa processors, It is also used as an alternative to using a proprietary operating system and toolchain. » 009.01.Linux Boot Process
009.01.12.2.Can you describe the significance of the Power-On Self-Test (POST) in the BIOS/UEFI phase of the Linux boot process and explain how it ensures the basic functionality of hardware components before proceeding with the boot sequence?
POST is used to check the hardware functionality, it ensures the basic functionality by sending a signal to each component and responds if the reply is there, else doesn't.
The Power-On Self-Test (POST) is employed to check the hardware functionality during the BIOS/UEFI phase. It ensures basic functionality by sending signals to each hardware component and expects a response. If a component responds as expected, the system proceeds with the boot process; otherwise, it identifies potential issues or errors.
The POST process starts when the electrical signal received is in " Power Good phase ". This is where a self-test to check the signals of all the connected hardware are good and all the hardware connected is in normal operating conditions. Hardware such as CPU, GPU, SSD any external memory devices, keyboards, display, etc are connected and there is no wrong signal received during the powerup phase. If any hardware gives a wrong signal the BIOS firmware will not be booted and the system will not boot.
POST, Power On Self Test, as the name suggests is a self test done when device is powered ON. Before BIOS directs to the address of Boot Loader, a basic test is done with all connected hardware. A test signal is sent and if it is acknowledged successfully then only BIOS refers to the address for Boot Sequence.
POST is used to check the basic functionality of the hardware by sending signal to each hardware comment and check for its response . Once its gets the response the system proceeds with boot process .
A power-on self-test (POST) is a set of routines performed by firmware or software immediately after a computer is powered on, to determine if the hardware is working as expected. The process would proceed further only if the required hardware is working correctly, else the BIOS(Basic Input Output Software) would issue an error message.
The error message could consist of text messages on the console or audio in the form of beeps.
When we turn on the computrer the first software that runs is BIOS/UEFI .it performs the power on self test which is commonly known as POST .POST does couple of tasks which are mentioned below
1.verify the hardware components and peripherals
2.carry out tests to ensure computer is in proper working condition
if any error arises during the test it prints the error on screen and if it fails to detect RAM POST triggers beeping sound.
The Power On Self-Test (POST) in BIOS/UEFI is important as it checks the hardware components like ARM,CPU and storage during startup it ensures that system is functioning properly and identifying if there is any issue before the operating system loads. This helps to identify hardware problems early and ensures smooth boot process and stability of the system.
when ever we turn on power of system ,BIOS /UEFI performed POST (Power On Self Test) to ensures that the system is functioning properly with their peripherals. if any issue is found out then it basically show error message on screen .
