CSSLP · Question #157
Which of the following are the principle duties performed by the BIOS during POST (power-on- self- test)? Each correct answer represents a part of the solution. Choose all that apply.
The correct answer is A. It provides a user interface for system's configuration. B. It identifies, organizes, and selects boot devices. C. It delegates control to other BIOS, if it is required. D. It discovers size and verifies system memory. E. It verifies the integrity of the BIOS code itself. During the Power-On Self-Test (POST), the BIOS performs critical duties including verifying its own code integrity, discovering and verifying system memory, identifying boot devices, providing a user interface for configuration, and delegating control to other BIOS modules.
Question
Which of the following are the principle duties performed by the BIOS during POST (power-on- self- test)? Each correct answer represents a part of the solution. Choose all that apply.
Options
- AIt provides a user interface for system's configuration.
- BIt identifies, organizes, and selects boot devices.
- CIt delegates control to other BIOS, if it is required.
- DIt discovers size and verifies system memory.
- EIt verifies the integrity of the BIOS code itself.
- FIt interrupts the execution of all running programs.
How the community answered
(27 responses)- A93% (25)
- F7% (2)
Why each option
During the Power-On Self-Test (POST), the BIOS performs critical duties including verifying its own code integrity, discovering and verifying system memory, identifying boot devices, providing a user interface for configuration, and delegating control to other BIOS modules.
The BIOS provides access to setup utilities (often called CMOS setup or UEFI setup) which serves as a user interface for configuring various system settings, including boot order and hardware parameters.
POST involves the BIOS scanning for and initializing storage controllers and drives, then identifying and organizing potential boot devices according to the configured boot order to select the primary boot device.
The main BIOS can delegate control to other specialized BIOS modules, such as a video card's BIOS (VGA BIOS) or a RAID controller's BIOS, to initialize and manage specific hardware components.
One of the earliest and most critical POST duties is to detect the installed system memory (RAM), determine its total size, and perform a basic integrity check to ensure it is functional.
The BIOS performs a self-check, often using a checksum, to verify the integrity of its own firmware code, ensuring it has not been corrupted or tampered with before proceeding with the boot process.
POST occurs before the operating system loads and any applications begin to run; therefore, the BIOS cannot "interrupt the execution of all running programs" because no programs are running yet.
Concept tested: BIOS POST duties
Source: https://learn.microsoft.com/en-us/windows-hardware/drivers/bringup/boot-sequence-of-an-x86-based-pc
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