What is BIOS in Computer? | JKSSB Mock Test
What is BIOS in Computer? – Meaning, Functions, Types, and Update Explained (2025)
If you’ve ever turned on your computer and seen a black screen with text before Windows starts — that’s the BIOS at work! In this guide, we’ll explain What is BIOS in computer and its function, types of BIOS, BIOS in laptop and motherboard, and even where BIOS settings are stored. Let’s get started!
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What is BIOS in Computer?
BIOS stands for Basic Input Output System. It is the first program that runs when you power on your computer. The BIOS checks your system hardware, loads essential startup files, and helps your operating system (like Windows or Linux) boot properly.
In simple terms, BIOS acts as a bridge between your computer’s hardware and software.
What is BIOS in Laptop?
The BIOS in laptop works just like the one in desktop computers. It initializes components like RAM, processor, and storage devices during startup. However, laptop BIOS also manages battery functions, integrated graphics, and thermal settings for efficient power usage.
What is BIOS in Computer Motherboard?
Every motherboard comes with a BIOS chip — a small memory chip soldered onto it. This chip stores the BIOS firmware, which is responsible for controlling how the system hardware interacts with the operating system.
Without this BIOS chip, your computer would not even start — it’s that essential!
Main Functions of BIOS
The main functions of BIOS include:
- 1. Power-On Self Test (POST): Checks the system hardware when the computer is powered on.
- 2. Bootstrap Loader: Finds and loads the operating system into the main memory.
- 3. BIOS Drivers: Provides low-level drivers for controlling keyboard, display, and other hardware.
- 4. CMOS Setup: Allows users to configure system settings like date, time, boot order, etc.
- 5. System Security: Enables password protection and secure boot functions.
Function of BIOS – Explained
| Function | Description |
|---|---|
| Power-On Self Test (POST) | Tests system components like RAM, CPU, and storage before booting. |
| Bootstrap Loader | Locates the operating system and loads it into main memory. |
| CMOS Setup Utility | Stores configuration settings like system time, date, and boot sequence. |
| BIOS Drivers | Controls basic hardware like keyboard, disk drives, and display. |
| Security Management | Provides password protection and secure boot for system safety. |
Types of BIOS
There are mainly two types of BIOS used in modern computers:
- 1. Legacy BIOS: The traditional BIOS used in older systems. It uses MBR (Master Boot Record) and supports drives up to 2 TB.
- 2. UEFI (Unified Extensible Firmware Interface): The modern replacement for legacy BIOS. It supports faster booting, larger storage drives (over 2 TB), and advanced graphics interfaces.
| Feature | Legacy BIOS | UEFI BIOS |
|---|---|---|
| Boot Mode | MBR (Master Boot Record) | GPT (GUID Partition Table) |
| Storage Support | Up to 2 TB | More than 2 TB |
| Boot Speed | Slower | Faster |
| Interface | Text-based | Graphical Interface |
| Security | Limited | Secure Boot, TPM Support |
Where are the BIOS Settings Stored?
The BIOS settings are stored in a small memory chip called CMOS (Complementary Metal Oxide Semiconductor). Even when the computer is turned off, these settings are preserved using a small CMOS battery on the motherboard.
When the battery runs out, BIOS settings may reset to default values.
What is BIOS Update?
A BIOS update is a process of replacing the old BIOS firmware with a newer version provided by the motherboard manufacturer.
It can:
- Improve hardware compatibility
- Fix system bugs or security issues
- Enhance performance and stability
Note: BIOS updates should be done carefully. An incorrect update may make your computer unbootable.
BIOS vs UEFI – Key Difference
| Criteria | BIOS | UEFI |
|---|---|---|
| Full Form | Basic Input Output System | Unified Extensible Firmware Interface |
| Boot Method | Legacy (MBR) | Modern (GPT) |
| Boot Time | Slower | Faster |
| Security Features | Basic Passwords | Secure Boot, TPM |
| Graphical Interface | No | Yes |
Frequently Asked Questions (FAQ)
Q1: What is BIOS and its main function?
A: BIOS is the Basic Input Output System that initializes hardware and helps the operating system load during startup.
Q2: What is BIOS in computer motherboard?
A: BIOS is stored in a chip on the motherboard that manages hardware communication and system startup.
Q3: Where are BIOS settings stored?
A: BIOS settings are stored in CMOS memory, powered by a small battery on the motherboard.
Q4: What is BIOS update?
A: BIOS update means installing a new version of BIOS firmware to fix bugs or support new hardware.
Q5: What are the types of BIOS?
A: There are two main types – Legacy BIOS and UEFI BIOS.
Q6: What is BIOS in laptop?
A: BIOS in laptops manages startup hardware checks, battery management, and power efficiency features.
Conclusion
In summary, the BIOS (Basic Input Output System) is the first and most important firmware that helps your computer boot and run smoothly. It performs essential tasks like POST, loading the OS, and managing hardware configurations. With modern UEFI BIOS now replacing legacy versions, computers boot faster and more securely than ever.
