The first thing to understand is that BIOS and CMOS are obviously not the same, but they go hand in hand and you cannot understand one without the other. So, to know their differences, we must first understand their meaning and the function they perform.
BIOS vs CMOS, connections and differences
Having said that, BIOS is a logical part of the PC, that is, a program responsible for properly starting the PC. Its acronyms start at Basic input-output system or basic input and output system and is nothing more than firmware, a very compact and basic software that is installed in a ROM memory.
This memory comes in the form of a chip that is powered by a power source external to the power supply itself of the PC, such as a battery, which on the other hand is the most common system in the computer. ‘industry.
What is wanted is that this chip does not lose the configuration of the software that it included, like the boot options of the hard drives, the configuration of the RAM memory, the options selected at the start of the system, or all. which allows to enable or disable in the BIOS itself. Another key point that is often overlooked is that thanks to this battery, the system time and date are saved, so if we don’t have auto-sync options for these two settings in Windows, the ones that will appear this are those of the BIOS itself.
Therefore, this battery is a fundamental part of the work that we will do in the BIOS, where, depending on the model and the capacity they acquire, they tend to last an average of 10 years without having to be replaced.
CMOS is the physical part of the equation
This chip we talked about is nothing more than the CMOS of the system, where it is formed and created as a semiconductor chip with metal oxide whose sole purpose is to house the BIOS, its configuration, the updates and possible failures, which have them.
Therefore, BIOS vs CMOS are part of a whole which is the motherboard and the system. The first is the logical part, the second the physical part and obviously they cannot live without each other. There are several other curiosities, because CMOS takes its name from the manufacturing technology of the chip itself, that is, it is misnamed.
CMOS is an integrated circuit manufacturing technology, where there are processors, for example, so it’s as if instead of saying CPU, we say CMOS. The correct name of the chips that host the BIOS is EEPROM which is logically created by CMOS.
Therefore, EEPROM is a type of electrically erasable programmable read and write chip that allows data to be overwritten if the system allows it. On motherboards, this is very useful if there is BIOS corruption and we need to overwrite it. Previously this w as not possible from the motherboard itself and an EEPROM programmer was required to properly flash the chip.
CMOS vs EEPROM, why so much confusion?
Therefore, the so famous “clear CMOS” should actually be called “clear EEPROM” completely correct and precise, much more successful without a doubt. By understanding the differences, we can already discern what is right and what is wrong. Another example of this is precisely talking about CMOS settings, when in reality we mean by UEFI settings.
It should also not be pronounced as a BIOS setting, mainly because motherboards for 10 years have no BIOS, but UEFI as such. Out of curiosity, although EEPROM chips with CMOS are growing in size, the reality is that the UEFI or BIOS, if applicable, would only stay in the first MB, because what is being tried is that it weighs as little as possible, but add as many instructions as possible.
Among other things, the EEPROM stores the compatible hardware that must be recognized, normally it has in its possession the microcodes of the manufacturer of the processors for this platform, in addition to recognizing for example SSDs, graphics cards and other devices with which it can exchange or SKU or ID directly.
Normally, in these cases, all these devices are of the type Plug in and use, so EEPROM and BIOS / UEFI have nothing to configure, just check in the case of CPU, RAM and GPU that they are compatible with the SKUs they have saved in their microcodes. Otherwise the motherboard will not turn on and we will have a nice black screen.
This often happens with several series of processors for the same socket. The UEFI update is decisive if what we want is for the CPU to be recognized by it. In graphics cards this is much more unusual, but there are also cases of problems due to the inability to read the SKUs or IDs of the models and you even have to enable CSM to be able to access Windows.
In short, we are talking about a whole where some are the physical part and others the logical part, but it goes without saying that they are not even by far the same and yet many continue to be confused precisely by the same fact. that there are people who say BIOS instead of UEFI or even CMOS instead of EEPROM. So, from now on, we can correctly name each of them without making a mistake.
