📖 What is BIOS?
BIOS (Basic Input/Output System) is firmware pre-installed on the motherboard. It initializes hardware during the boot process, performs a Power-On Self-Test (POST), and loads the operating system. Modern systems increasingly utilize UEFI, a more advanced successor to BIOS, offering enhanced features and security.
"While UEFI is prevalent, the exam still covers BIOS fundamentals. Focus on understanding POST error codes, BIOS settings related to boot order, and the ability to reset or flash the BIOS. Distinguish between BIOS and CMOS battery functions."
📚 Certification: CompTIA A+ Certification Exam Core 2 (220-1102)
🔑 What are the Key Concepts of BIOS?
- ▸ POST (Power-On Self-Test) is a crucial BIOS function that checks hardware components for functionality before OS loading.
- ▸ BIOS settings control boot order (which device the system tries to boot from), impacting troubleshooting and OS installation.
- ▸ The CMOS battery maintains BIOS settings when the system is powered off; failure causes settings to revert to default.
- ▸ BIOS flashing (updating) can resolve compatibility issues or add new hardware support, but carries risk if interrupted.
- ▸ Legacy BIOS uses a Master Boot Record (MBR) while UEFI uses GUID Partition Table (GPT) impacting drive size and boot capabilities.
🎯 How does BIOS appear on the 220-1102 Exam?
You may be asked to identify the component responsible for displaying error messages during the initial startup phase, before the OS loads.
A scenario might describe a computer failing to boot, and you must determine which BIOS setting to adjust to prioritize the correct boot device.
Expect questions about troubleshooting a system that repeatedly displays a specific POST error code – you’ll need to know what the code indicates.
❓ Frequently Asked Questions
What happens if the CMOS battery fails?
A failing CMOS battery will cause the BIOS settings to reset to default each time the computer is powered off. This often results in boot errors or incorrect system time.
What are the risks associated with flashing the BIOS?
A failed BIOS flash can render the motherboard unusable (bricked). Ensure a stable power supply and follow manufacturer instructions precisely. Many modern BIOS have recovery options.
How does BIOS interact with the operating system?
BIOS initializes the hardware and then hands control over to the operating system. It provides low-level routines the OS can use to interact with hardware, but the OS largely manages hardware after boot.