UEFI means Unified Extensible
Firmware Interface. It is the successor to EFI, which stands
for Extensible Firmware Interface. During 1995, Intel realized
that the IBM BIOS (Basic Input/output System) style
firmware interface had many inconvinient limitations. These limitations didn’t
really affect the average users, but they made it very arduous to produce
high-performance servers, namely. As a result, Intel started developing
the EFI in 1998. In 2005, Intel ceased development of the EFI
and contributed it to the Unified EFI Forum . Intel still continues
to license the EFI specification , but the UEFI
specification is owned by the Forum. The advantages of UEFI
over BIOS is very high, a few notable ones are:
A
powerful pre-boot environment capable of running many applications -
- CPU-independent
architecture ( ARM Arch32, Arm Arch64, Itanium, x86, x64)
- legacy
booting and BIOS interface
compatibility
- Dependable
ability to boot from disks larger than 2TiB (not Terabyte)
If you want to organize and keep track of
partitions on a disk, whether you are using HDD or an SSD, you need what’s
known as a partition table, such as GPT (GUID Partition Table)
and MBR (Master Boot Record). A legacy BIOS
system is only able to boot from MBR partition tables (there are
some exceptions) and the MBR specification can merely address up to
2TiB of disk space, which results in a BIOS system being able to
boot from disks of 2TiB or lesser.
Other disadvantages of MBR
formatted disks include a limited bootable partitions and boot manager. MBR
only uses a one sector of the disk for its data, called the boot sector which is the root cause of these problems.
Again, disappointed with the BIOS
and MBR booting , Intel developed GPT
specifications to remedy the shortcomings of the available options.
The GPT specification allowed the disks of significantly hugeee size
(up to Zettabytes in size) just for partition addressing, 64B instead of the
16B used by MBR. Due to GPT addressing sectors as
opposed to individual bits or bytes GPT can partition disks of varying
sizes depending on the sector size.
One has to make Petabyte and Exabyte disks
before one can think of reaching the GPT partition addressing
limitation. Boot code and partition table are also separate in GPT.
The signing of the executable files is
called Secure Boot . If the signature matches a signature that has been
previously registered with the UEFI firmware, then the
motherboard will allow it to boot.
Well there you have it the basic Difference among UEFI, BIOS, GPT, MBR .You can dig up more in wikipedia .Be sure to comment and share ;) .
