📗 BIOS
BIOS stands for Basic Input/Output System. It is a firmware that is responsible for initializing the hardware components of a computer and preparing them for the operating system. BIOS is usually stored on a non-volatile memory chip on the motherboard of a computer. In this tutorial, we will discuss BIOS in detail, including its functions, settings, and how to access it.
✔ Functions of BIOS:
Power-on self-test (POST): When a computer is turned on, BIOS performs a series of checks called the POST. This test checks the hardware components of the computer, such as the memory, CPU, and storage devices, to ensure they are functioning properly.
Boot sequence: After the POST, BIOS identifies and initializes the boot device, which contains the operating system. The boot device can be a hard drive, solid-state drive, CD/DVD, or USB drive.
System configuration: BIOS stores information about the hardware configuration of the computer, such as the number of memory modules, hard drives, and peripheral devices. This information is used to configure the system and allocate resources to the devices.
Firmware updates: BIOS firmware can be updated to fix bugs, improve performance, and support new hardware.
✔ BIOS Settings
BIOS settings are stored in non-volatile memory, which means they are retained even when the computer is turned off. The settings can be accessed and modified by entering the BIOS setup utility, which is usually accessed by pressing a key during the POST. The key may vary depending on the computer manufacturer, but it is usually displayed on the screen during the boot process.
The BIOS settings can be divided into several categories, including:
Main: This category contains general system information, such as the time and date, system language, and boot device priority.
Advanced: This category contains advanced system settings, such as the CPU settings, memory settings, and hard drive settings.
Power management: This category contains settings related to power management, such as the sleep and hibernation modes.
Security: This category contains settings related to system security, such as passwords, secure boot, and antivirus.
✔ Accessing BIOS
To access BIOS, follow these steps:
Turn on the computer and look for the key to access BIOS setup utility. This key varies depending on the computer manufacturer, but it is usually displayed on the screen during the boot process.
Press the key repeatedly until the BIOS setup utility appears.
Navigate through the BIOS settings using the arrow keys and modify the settings as necessary.
Press F10 to save the changes and exit BIOS setup utility.
BIOS is an essential part of a computer that initializes the hardware components and prepares them for the operating system. It performs a series of checks during the power-on self-test and identifies and initializes the boot device. BIOS settings can be accessed and modified by entering the BIOS setup utility, which can be accessed by pressing a key during the POST.
📗 Master Boot Record
Master Boot Record (MBR) is a special type of boot sector that is located at the beginning of a hard disk or other storage device. It contains information about the disk's partition table and a small program called the boot loader that loads the operating system. In this tutorial, we will discuss MBR in detail, including its structure, functions, and how it is used in the boot process.
✔ Structure of MBR
MBR is located in the first sector of the disk and occupies 512 bytes of storage. It consists of three parts:
Boot loader: The first 446 bytes of the MBR contain the boot loader program. This program is responsible for loading the operating system from the disk.
Partition table: The next 64 bytes of the MBR contain the partition table. This table contains information about the disk's partition layout, such as the starting and ending sectors of each partition, the partition type, and the active partition.
Boot signature: The last two bytes of the MBR contain a boot signature (0x55 and 0xAA) that indicates that the MBR is valid.
✔ Functions of MBR
Boot loader: The boot loader program in the MBR is responsible for loading the operating system from the disk. It reads the partition table to locate the active partition and then loads the operating system's boot sector from the active partition.
Partition table: The partition table in the MBR contains information about the disk's partition layout, such as the starting and ending sectors of each partition, the partition type, and the active partition. The active partition is the partition that contains the boot loader and the operating system.
Disk signature: MBR also stores a unique identifier called the disk signature that can be used to identify the disk.
✔ How MBR is used in the boot process
When a computer is turned on, the BIOS performs the power-on self-test (POST) and then reads the MBR from the first sector of the boot device. The boot loader program in the MBR is then executed, which reads the partition table to locate the active partition. The boot loader then loads the operating system's boot sector from the active partition and transfers control to the operating system.
✔ Limitations of MBR
MBR has some limitations, including:
Limited to four primary partitions: MBR can only have up to four primary partitions or three primary partitions and one extended partition.
Limited disk size: MBR can only address disks up to 2 terabytes in size. This is due to the use of 32-bit disk addresses in the partition table.
Vulnerable to malware: MBR is vulnerable to malware that can overwrite the boot loader or partition table, rendering the system unbootable.
MBR is a special type of boot sector that is located at the beginning of a hard disk or other storage device. It contains information about the disk's partition table and a small program called the boot loader that loads the operating system. The boot loader program in the MBR reads the partition table to locate the active partition and then loads the operating system's boot sector from the active partition. MBR has some limitations, including a limited number of partitions and disk size, and is vulnerable to malware attacks.
Thanks for reading, and happy coding!
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