DUAL BOOTING KNOWING LEGACY BIOS & UEFI FIRMWARE

KNOWING MBR & GPT PARTITION

D.BHARANI

AM.EN.U4CSE12013

General informations

Before dual booting there are certain things to be noted, to run system effectively

What is Legacy BIOS

What is UEFI

What is MBR partition

What is GPT partition

LEGACY BIOS

In IBM PC compatible computers, the Basic Input/Output System (BIOS), also known as System BIOS, ROM BIOS or PC BIOS, is a de facto standard defining a firmware interface.

The fundamental purposes of the BIOS are to initialize and test the system hardware components, and to load a bootloader or an operating system from a mass memory device.

The BIOS additionally provides abstraction layer for the hardware, i.e. a consistent way for application programs and operating systems to interact with the keyboard, display, and other input/output devices.

Variations in the system hardware are hidden by the BIOS from programs that use BIOS services instead of directly accessing the hardware.

UEFI

The Unified Extensible Firmware Interface (UEFI)  is a specification that defines a software interface between an operating system and platform firmware.

UEFI is meant to replace the Basic Input/Output System (BIOS) firmware interface, originally present in all IBM PC-compatible personal computers

UEFI can support remote diagnostics and repair of computers, even without another operating system.

Intel developed the original EFI (Extensible Firmware Interface) specification. Some of the EFI's practices and data formats mirror those from Microsoft Windows. 

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The original motivation for EFI came during early development of the first Intel–HP Itanium systems in the mid-1990s. BIOS limitations (such as 16-bit processor mode, 1 MB addressable space and PC AT hardware) were unacceptable for the larger server platforms Itanium was targeting.

The effort to address these concerns began in 1998 and was initially called Intel Boot Initiative; it was later renamed to EFI.

The current UEFI specification, version 2.4, was approved in July 2013.

Advantages

The interface defined by the EFI specification includes data tables that contain platform information, and boot and runtime services that are available to the OS loader and OS. UEFI firmware provides several technical advantages over a traditional BIOS system.

Ability to boot from large disks (over 2 TB) with a GUID Partition Table (GPT)

CPU-independent architecture

CPU-independent drivers

flexible pre-OS environment, including network capability

modular design

UEFI vs Legacy BIOS

UEFI enables better use of bigger hard drives.

Though UEFI supports the traditional master boot record (MBR) method of hard drive partitioning, it doesn't stop there,It's also capable of working with the GUID Partition Table (GPT), which is free of the limitations the MBR places on the number and size of partitions.

UEFI may be faster than the BIOS.

Various tweaks and optimizations in the UEFI may help your system boot more quickly it could before.

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However, UEFI is still not widespread.

Though major hardware companies have switched over almost exclusively to UEFI use, you still won't find the new firmware in use on all motherboards—or in quite the same way across the spectrum.

Many older and less expensive motherboards also still use the BIOS system.

MBR A master boot record (MBR) is a special type of boot sector at

the very beginning of partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond. The concept of MBRs was publicly introduced in 1983 with PC DOS 2.0.

The MBR holds the information on how the logical partitions, containing file systems, are organized on that medium

 This MBR code is usually referred to as a boot loader.

MBR partition entries and the MBR boot code used in commercial operating systems, however, are limited to 32 bits.

Therefore, the maximum disk size supported on disks using 512-byte sectors (whether real or emulated) by the MBR partitioning scheme (without using non-standard methods) is limited to 2 TB

GPT

GUID Partition Table (GPT) is a standard for the layout of the partition table on a physical hard disk, using globally unique identifiers (GUID).

Although it forms a part of the Unified Extensible Firmware Interface (UEFI) standard (Unified EFI Forum proposed replacement for the PC BIOS), it is also used on some BIOS systems because of the limitations of master boot record(MBR) partition tables, which use 32 bits for storing logical block addresses (LBA) and size information.

GPT allocates 64 bits for logical block addresses, therefore allowing a maximum disk size of 264 sectors

MBR vs GPT

Compared with MBR disk, A GPT disk can support larger than 2 TB volumes where MBR cannot.

A GPT disk can be basic or dynamic, just like an MBR disk can be basic or dynamic.

GPT disks also support up to 128 partitions rather than the 4 primary partitions limited to MBR.

Also, GPT keeps a backup of the partition table at the end of the disk.

Furthermore, GPT disk provides greater reliability due to replication and cyclical redundancy check (CRC) protection of the partition table. 

Method to find BIOS mode:(UEFI or LEGACY BIOS)

Just fire up MSINFO32 in cmd prompt

Steps to find GPT or MBR partition

In the system:

1. Open Disk Management: Start > Control Panel > Administrative Tools > Computer Management > Disk Management.

2.  Right click on the Disk # box

NOTE: The smaller box on the left, with the Disk #, not the larger volume boxes

3. Select Properties

4. Click the Volumes tab

5. Next to Partition Style, it will list the format as "Master Boot Record (MBR)" or “GUID Partition Table (GPT)”

REMEMBER!

It is not possible to convert MBR to GPT partition without formatting the disk

To convert MBR to GPT one should take a backup of all files to external hard disk , then format your disk.

Now make a new GPT partition

Installing Ubuntu alongside of Windows – through bootable USB

Minimum Requirements for Ubuntu

386 MiB of system memory (RAM)

4 GB of disk space

! Remember this before installing Ubuntu into the system

Bootable softwares

Most common bootable softwares

UNetbootin

WinSetupFromUSB

LinuxLive USB Creator

Use any of these,to make USB bootable

Also select Distribution(say Ubuntu) and select version(say 12.04 or any desired version)

UNetbootin Interface

AFTER INSTALLATION COMPLETE,IT WILL ASK YOU FOR REBOOT.

REBOOT to get into BOOT menu

BOOT device

Some common buttons to get boot menu(shown below)

Esc or F12 or F9 or F8

Either any one of these buttons will bring boot menu and this solely depends on system manufacturer

Click USB DEVICE(here KingstonDT Ultimate for legacy mode installation or UEFI: KingstonDT Ultimate for UEFI mode installation)

You'll be greeted by the "Preparing to install Ubuntu" screen, exactly as below

Select "Install third-party software" as done in the screenshot above.

Or if you have the extra time you can also select "download updates while installing" as well. Then click continue

Those of you that have current Windows installations or are going to dual-boot with another existing OS will be presented with a screen similar to below:

You can choose "something else" and create your own partition scheme and sizing

Having selected the "something else" option you will be presented with the following window:

Partitions are also shown after the drive letters. So if I had 2 partitions on first disk, they would be identified as:• Sda1 – 1st drive, 1st partition• Sda2 – 1st drive, 2nd partition

Disk drives

If you have more than one disk, they will show up as /dev/sda, /dev/sdb etc.

Firstly, identify your Windows installation. In this case, it's sda1 (which is my first hard disk, first partition). What you see depends on how you created the extra space.

Here Windows is resized and partitioned from within Windows, and left the free space ready to install Linux

 We now need create a minimum of two partitions:

Click "Add" and the following box will appear:

You can have a maximum of 4 primary partitions, or 3 primary partitions and 1 logical (which allows for another 64 partitions)

The size above is 10.00GB. e.g 1,000 = 1GB 10,000 = 10GB (Remember to leave enough free remaining space to create your SWAP partition!)

Root Partition

Location for new partition: e.g. do you want it at the start or end of the free space.

Select beginning.

Use as: Ext4 is the recommended file system for Ubuntu, much the same as NTFS is Windows.

SWAP is for SWAP space.

Mount point: This is where you want the partition to mount. E.g. we need a root partition, which in Linux is denoted by a "/".

Click OK once you have finished setting the partition information

SWAP AREA SETTING

You will now return to your partition screen, showing the root partition you just created.

Using the same methods as before, create a SWAP partition.

Set the size of your SWAP partition to at least the size of your available RAM.

For best performance it is recommended you have your SWAP partition at the beginning or end of your drive

Once you have done that, you should be looking at something like below.

/dev/sda1 is your Windows partition /dev/sda2 is your new root partition (Windows equiv. of C) /dev/sda3 is your SWAP space.

 click install now and proceed to the next step.

WHERE ARE YOU ?

It will automatically find where you are

Just double check it is correct, and then select continue.

KEYBOARD LAYOUT

Ensure the correct option is selected,

Selection will be automatically made for you

WHO ARE YOU ?

The computers name and username will automatically populate when you type your full name.

Fill in the details and then click continue.

FINAL INSTALLATION

The installation information screens will now appear as Ubuntu continues the installation

INSTALLATION COMPLETE

Once installation has finished, you will be presented with the following box:

Select "restart now" and when requested, remove your installation CD, then press enter to reboot.

GRUB MENU After RESTART you will see a GRUB menu like this

Click Ubuntu to load Ubuntu OS as shown

LOGIN SCREEN

NEW HOMESCREEN

SUCCESSFULLY DUAL BOOTED

THANK YOU