BIOS and UEFI
Firmware interfaces for computers.
BIOS (Basic Input/Output System) and UEFI (Unified Extensible Firmware Interface) are both firmware interfaces that serve as the critical link between a computer's hardware and its operating system. BIOS is the traditional firmware interface that has been used since the 1980s. It initializes and tests hardware components during the POST (Power-On Self Test) process and provides runtime services for operating systems and programs. BIOS uses a 16-bit architecture and can only address 1MB of memory during boot. It stores configuration settings in CMOS, powered by a small battery. BIOS typically uses a text-based interface and boots from Master Boot Record (MBR) partitioned drives, which limits partitions to 2TB. UEFI is the modern replacement for BIOS. Developed to address BIOS limitations, UEFI offers significant improvements. It uses a 32-bit or 64-bit architecture and can access full system memory during boot. UEFI supports GUI interfaces with mouse navigation, network booting, and remote troubleshooting. It boots from GUID Partition Table (GPT) drives, supporting partitions larger than 2TB. UEFI includes Secure Boot, which verifies the digital signatures of boot loaders to prevent unauthorized code execution. UEFI provides modular design with better extensibility than BIOS. It offers faster boot times by initializing multiple hardware devices simultaneously rather than sequentially. UEFI stores settings in NVRAM and can run EFI applications before loading the OS. Modern systems often include Compatibility Support Module (CSM) within UEFI to maintain backward compatibility with legacy BIOS-dependent operating systems and hardware. For CompTIA A+ certification, understanding both systems is essential as technicians will encounter both in the field, with UEFI becoming increasingly prevalent in newer systems.
BIOS (Basic Input/Output System) and UEFI (Unified Extensible Firmware Interface) are both firmware interfaces that serve as the critical link between a computer's hardware and its operating system. …
Concepts covered: CMOS and BIOS settings, Basic Input/Output System (BIOS), Unified Extensible Firmware Interface (UEFI), Secure Boot, BIOS vs UEFI, BIOS and UEFI Configuration, UEFI vs. Legacy BIOS, BIOS/UEFI password protection, POST (Power-On Self-Test), Legacy Boot, BIOS-based virtualization, BIOS/UEFI update process, BIOS and UEFI Updates, UEFI Variables, Boot Process
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