CMOS and BIOS settings

5 minutes 5 Questions

The Complementary Metal-Oxide-Semiconductor (CMOS) is a type of integrated circuit where data is stored regarding system configurations. The CMOS battery supplies power to maintain these settings when the computer is turned off. Fields like date, time, hard drive information, and boot priorities ar…

Guide: CMOS and BIOS Settings for CompTIA A+ Exam

What it is:
BIOS stands for Basic Input/Output System. It's the program a personal computer's microprocessor uses to start the computer system after it is powered on. CMOS (Complementary Metal-Oxide-Semiconductor) is a chip where the BIOS settings and your hardware settings are stored.

Why it is important:
Knowing how to handle the BIOS and CMOS settings is vital for managing a computer's hardware, troubleshooting issues, and improving its efficiency. The BIOS is a fundamental component that handles data flow between the computer's operating system and attached devices. The CMOS houses necessary information, like system time and date and hardware settings.

How it works:
When you power on your computer, BIOS initializes and tests the system hardware components, then loads the boot loader from the hard drive to boot your operating system. Using the CMOS setup, you can change the values of these hardware components if needed. For example, to change the system’s boot order, you would navigate through the BIOS setup using the keyboard keys.

Exam Tips - Answering Questions on CMOS and BIOS settings:
- Understand the basics of BIOS including its role in booting up a PC, BIOS versions and the BIOS setup interface.
- Be familiar with various BIOS and UEFI settings – boot sequence, enabling and disabling devices, date/time settings etc.
- Understand the purpose and function of CMOS and how it relates to BIOS.
- Learn how to reset the BIOS or UEFI to its default settings, update BIOS firmware, and back up BIOS settings.
- Remember that CMOS houses the BIOS settings and configurations, handling checksum errors here could be essential.
- Practical experience is crucial. Getting hands-on experience with BIOS and CMOS settings will be immensely helpful

Test mode:

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Question 1

A user reports that their computer's date and time are resetting every time they power off the system. What is the likely cause and the best solution?

Reset the BIOS settings to default. Replace the CMOS battery. Reinstall the operating system. Upgrade the BIOS.

Correct Answer: Replace the CMOS battery.

The most likely cause of the computer's date and time resetting every time the system is powered off is a dead or failing CMOS battery. The CMOS battery maintains the BIOS settings, including the date and time, when the computer is turned off. If the battery is dead or failing, it will not be able to maintain these settings, causing them to reset each time the computer is powered off. Replacing the CMOS battery is the best solution to this problem. Reinstalling the operating system, upgrading the BIOS, or resetting the BIOS settings to default will not address the underlying issue of a dead or failing CMOS battery.

Question 2

After replacing a CMOS battery, which of the following should be done to ensure proper BIOS functionality?

Reset the BIOS to default settings. Update the date and time settings in the BIOS. Reinstall the operating system. Replace the CPU.

Correct Answer: Update the date and time settings in the BIOS.

After replacing the CMOS battery, the BIOS settings, including the date and time, will revert to default values. To ensure proper BIOS functionality, it is necessary to enter the BIOS setup utility and manually update the date and time settings to the correct values. Resetting the BIOS to default settings is not required, as the battery replacement already resets the settings. Reinstalling the operating system is unnecessary, as it does not affect the BIOS settings. Replacing the CPU is also not needed, as it is unrelated to the CMOS battery replacement process.

Question 3

A computer is not detecting a newly installed PCIe device. What should be done in the BIOS settings to resolve the issue?

Revert to the previous BIOS version. Disable onboard devices. Enable PCIe support. Enable Secure Boot.

Correct Answer: Enable PCIe support.

To resolve the issue of a computer not detecting a newly installed PCIe device, the correct step is to enable PCIe support in the BIOS settings. This setting allows the system to recognize and communicate with PCIe devices. Reverting to a previous BIOS version may cause compatibility issues and is not a reliable solution. Disabling onboard devices is unnecessary and may even prevent other components from functioning properly. Enabling Secure Boot is unrelated to the detection of PCIe devices and is used for security purposes. Therefore, enabling PCIe support in the BIOS settings is the most appropriate action to resolve the issue.

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