We have heard of the BIOS but we do not know what it refers to and what server in a computer "> In this guide we will show you in practice what the BIOS is and what it is used for, how to access it and what can be done inside it ; in addition to the BIOS we will also show you its latest evolution, called UEFI, which improves the interface and some functions, while maintaining all the functions we were used to on old BIOSes (PCs up to 7-8 years ago). READ ALSO: How to reduce the duration time of the BIOS and the boot of the PC
What is the BIOS
BIOS stands for Basic Input-Output System and is the first code that is loaded from a computer when it is turned on (i.e. the instant we press the power button). This programming code is not stored in the hard disk or in the SSD, but resides on a dedicated chip of the motherboard.
The BIOS is very important for the computer to work properly: first start the Power-on self-test ( POST ), i.e. the pre-boot sequence where the computer hardware devices are recognized (practically it is the black screen that appears on the start, where there are writings that appear fast) and then load the bootloader, which takes care of searching and starting the operating system.
In order to access the BIOS, you must restart the computer and use the exact procedure (of the keys to be pressed quickly on the keyboard) to enter or open the BIOS on all computers ; some of the keys most used for accessing the BIOS are CANC or F2. The access sequence must be performed immediately after the computer has started, already in the POST phase, so as to prevent the bootloader from starting and accessing the BIOS management screen.
Characteristic of the old BIOS is the absence of a pointing system: to be able to move between the menus we will have to use the directional keys on the keyboard, since the mouse will not be recognized by this system. This makes the BIOS slightly uncomfortable to use for those who are not accustomed to using the keyboard to move around the menus.
Two of the main functions of the BIOS is to change the boot order of the computer and boot the computer from USB
What is UEFI
UEFI is the direct evolution of BIOS, to which is added a mouse manageable interface (thanks to the drivers preloaded directly in the system) and much simpler menus to manage even for less expert users. UEFI also integrates new security systems (such as Secure Boot, necessary on some computers equipped with Windows 8.1 and Windows 10), a quick start system (which speeds up the transition to the bootloader during startup) and new menus to perform the 'overclocking of computer components, so as to be able to effectively increase PC performance. The sequences for accessing UEFI are the same as for BIOS, so it will be sufficient to use the right keys in the POST phase to be able to use it (usually the CANC and F2 keys, to be pressed repeatedly at startup).
Currently all systems integrate UEFI as a boot system, so don't be surprised when we run the sequence to access the BIOS and find ourselves with a profoundly different menu.
In another article, the guide to change from BIOS to UEFI on Windows 10 PC .
What can we do in the BIOS / UEFI
But what can we actually do within the BIOS? The fact that it is a hidden menu (not accessible without a particular key sequence) makes it immediately clear that BIOS and UEFI are components of the system that it is better not to touch : as long as everything works correctly, there is really no need to access the BIOS or UEFI to change hardware and motherboard related settings.
If instead we notice some unexplained computer slowdowns or we want to change the boot device (as in the case of the guide in which we have seen how to transfer Windows to another PC or disk, without reinstalling and losing data ), these menus are the only way to do it. Based on what we need to do, there is a dedicated menu within BIOS:
- Boot : in this menu we can change the boot devices, so as to start Windows from a USB stick or try a GNU / Linux distribution, without touching the primary operating system.
- Security : here we can find all the security-related settings, with the possibility of adding a system boot password or a password to access the BIOS, excellent for protecting computers from accidental changes (for example on company computers). In this menu we can also find the item Secure Boot, useful for increasing the security of recent Windows systems.
- Advanced : in this menu we can find the advanced settings of the motherboard, with which we will be able to improve the performance of the CPU, RAM and the integrated video card (if present).
If we use UEFI, the first screen at login could be very different: it is often a simplified version of the items normally visible on the BIOS, with information on the speed of the fans, on the electrical consumption and on the temperature of the fundamental components of the PC. In this screen we can quickly adjust some settings such as boot devices, the type of automatic overclocking to be applied to the system and other minor information.
If we need all the UEFI items, it is usually sufficient to click on the Advanced Mode menu to unlock the menus, quite similar to those seen on the BIOS.
We remind you that in UEFI we can use the mouse to navigate the menus and select items.
Conclusions
The BIOS or UEFI are very important components inside the computer, which should be "touched" only if strictly necessary: we can compare them to the bones of the human body, since just like the bones until they break they do not feel their presence!
If we notice a problem with the BIOS and we don't know how to solve it, we invite you to read our guide on how to reset the BIOS by clearing the CMOS memory and removing the buffer battery .
READ ALSO: What happens when you turn on your computer and why it can fail
