The BIOS (Basic Input/Output System) plays a crucial role in the startup and initialization of a computer system. It is a fundamental software component that is stored in a memory chip on the motherboard.
The BIOS includes parameters like system date and time, CPU settings and more.
The BIOS handles the hardware checks at a low level, before the system starts. The sequence is called Power-On Self-Test (POST). The BIOS ensures that the essential hardware components (such as the CPU, RAM, storage devices, and peripherals) are functioning correctly. If any issues are detected during POST, the BIOS may display error messages or beep codes to indicate the problem.
The BIOS is also responsible for locating and loading the operating system (OS) from a bootable storage device. It does this by searching for a special bootloader program on the selected storage device, which then starts the OS loading process.
You can access the BIOS by pressing a special key at startup (F2 on Dell systems). You can then access and modify the settings through the BIOS setup. This is where you can change the hardware settings or disable a device.
This is a common example of a situation where you need to change a value in the BIOS.
When you enable BitLocker and the user has a docking station, you may encounter the following issue: The external keyboard might not work at the BitLocker stage.
To resolve this, on Dell computers you need to access the BIOS and go either to:
- Bios Integrated Devices and then "Enable Thunderbolt Boot Support"
- PostBehavior and for Fastboot select "Thorough mode"
Manufacturers usually release BIOS updates to add new features, improve compatibility, or fix security vulnerabilities. It is especially important to install these updates regularly to ensure your computer runs smoothly and securely. For Dell systems, you can use tools like Dell Command Update or Dell Support Assist to check for available updates on each system. HP provides HP Support assistant. Lenovo uses Lenovo Vantage. If you use a different brand, check with your manufacturer.
BIOS is quite old now. It still uses a text-based interface and has seen limited updates over the years. It cannot handle disks larger than 2.2 TB. That's why BIOS has been superseded by UEFI (Unified Extensible Firmware Interface) which offers a graphical user interface and supports more advanced features. For example, UEFI initializes hardware components in a more parallel and efficient manner than BIOS, resulting in faster boot times. UEFI also supports Secure Boot, which verifies the authenticity of the bootloader and operating system to enhance security. Some UEFI implementations include network boot options and diagnostic utilities for troubleshooting hardware issues.
You can check whether your computer is using BIOS or UEFI by running msinfo32 in Windows. The System Information window will open. Click on the System Summary item. Then locate BIOS Mode and check the type of BIOS - Legacy or UEFI.
Look here to read more about the differences between Master Boot Record (MBR) and GPT (GUID Partition Table) disks.
While BIOS is compatible with both older and newer hardware and software, UEFI provides compatibility with legacy BIOS systems through a feature called Legacy Support or Compatibility Support Module (CSM). However, some older operating systems may not fully support UEFI booting.
Here are some training videos that might interest you.