BIOS and UEFI are the basic input and output systems of a computer. These small systems are the ones in charge of starting the base firmware of your computer, included in a chip of the base plate, and to put in operation the hardware so that, after the first seconds of ignition, it can begin to load the operating system. However, although roughly the purpose of both elements is the same, they are very different systems. In this article we explained in a comprehensive manner.
What is the BIOS and what are its main features
Traditionally, since 1975, the motherboards had a chip with the BIOS (Basic Input / Output System), this being the first program that runs when you start the computer. Over the years, this system has become increasingly complete allowing you to store all kinds of configurations, from the order of the boot disks (previously established by the cables themselves) to the configuration of the behavior of the Hardware, power options and even overclocking (which had to be configured before by the board jumper jumpers).
During POST (Power On Self Test) of the computer, in addition to checking that it has all the necessary peripherals to start and that both the memory and the hardware are in perfect condition, the hard disk or device that has the operating system has been loaded.
The BIOS was starting to get short. A new, more complete and secure system for motherboards was needed. Thus UEFI is born.
As the years went by, BIOS systems began to be somewhat short on all the security measures of modern operating systems. You must bear in mind that the first BIOS was intended for DOS , so trying to load a modern system like Windows 7 or Windows 8.1, many of the security measures needed to be safe on the network could not be enabled.
In addition, BIOS systems have other limitations in terms of hardware, such as that they can only boot from hard disks of 2.1 TB or more (an amount unthinkable in 1980 but common today) and, in addition, this system Basic load in 16-bit mode as it had to maintain full compatibility with older processors.
To access the BIOS settings simply press a specific key during the startup of the computer that will depend on the make and model of motherboard, but is usually, DEL, F2 or F12.
This is how the UEFI, the successor to the classic BIOS, was born.
UEFI in the current motherboard systems
In 2010 the new UEFI systems began to be used as standard . The main difference of this new system with the classic BIOS is that the code that is executed does it directly in 32 or 64 bits , leaving behind the code of 16 bits that was executed directly in the previous BIOS systems.
UEFI systems are ready to work hand in hand with today’s new hardware and to withstand several years in the future. This type of systems can boot from hard disks up to 9.4 ZettaBytes (more than 10 billion Terabytes), size 3 times higher than it is believed to be able to occupy the Internet today. In addition, this new system is compatible with the GPT partition tables, necessary to work with large hard disks.
These systems also have new security measures that protect both users and all data stored on the hard disk. One of these security measures is what is known as Secure Boot , a configuration that only allows to start and install digitally signed operating systems to avoid infecting malware or malicious software can run on the system before our OS.
UEFI systems are much closer to being an operating system than a simple firmware
The UEFI is not simply a substitute for the BIOS; it could come to be considered even as a small operating system, since it can be controlled from the mouse and in some concrete models it is possible to even run other applications above it, For example, hardware diagnostic tools.
How can I change my old BIOS for a new UEFI?
If you still have a system with a classic BIOS you must know that there is no way to update UEFI except to buy a new motherboard, since changing from one system to another is not like changing an operating system. Although you can download the latest version of the firmware for your board, this will remain BIOS and, although it can correct errors and improve the performance of the computer, you will not be able to enjoy the new features of this new UEFI system.
Any motherboard you buy today will already have this new system, and the hardware that will be connected to it will be ready to boot into these systems, so, in general, assembly and startup remain the same.
Normally both BIOS and UEFI are usually private, closed source, although there are already some free projects that allow you to install an OpenSource system on some particular models of motherboards, such as the LibreBoot project.