There is a long list of computing terms that have repeatedly confused novice computer users. Practically, the confusion surrounding the BIOS and the CMOS is one of the very tops in this list. I often hear people referring to the BIOS and CMOS interchangeably as if they are the same. If you are one of those people, I am going to try to help you understand the difference between BIOS and CMOS. Understanding the BIOS and the CMOS is a significant step to understanding how your computer works and staying ahead of your peers. Similarly, it will distinguish you from the regular Joe who barely knows a thing about computers. So let's dive right into it.
BIOS is the short form for the Basic Input/ Output System. It is a Read-Only Memory (ROM) chip located on a computer's motherboard. Essentially, the BIOS is responsible for allowing you to set up and configure your computer’s most basic settings. By that, I mean that the BIOS primarily contains computer instructions on how your computer should handle its basic hardware utilities.
Additionally, it contains Power-On Self-Test (POST), which is a diagnostic test. This test is meant to ensure that your computer has all the necessary parts that are functioning correctly, to ensure a successful booting up process. If POST detects an error, your computer will immediately produce beeping sounds while displaying information on where the malfunctioning might have occurred.
Given that the BIOS chip is a ROM memory, the next probable question would be; can we upgrade it or update it like other ROM memories? Well, the answer is Yes. The BIOS chip can be upgraded. However, unlike other forms of ROM, the BIOS chip can only be upgraded physically by interchanging the old one with a more advanced BIOS chip on the motherboard.
Again, it is possible to execute an update to the BIOS provided it is a flash BIOS. Updating the BIOS is, however, a delicate, complicated, and risky process that you probably wouldn't want to try without assistance from a technician. Nowadays, third-party software exists in the market that allows you to make updates to the BIOS. The main reason you'd want to update your BIOS is to add more features to your motherboard or to fix a persistent problem with the BIOS.
There are several different BIOS on the market today. If you are interested in knowing what type of BIOS is on your computer, you will need to access the BIOS setup. The BIOS or CMOS setup looks like this on my Dell machine running Windows 10 Pro.
In Windows 10, there are so many options available for you on the settings page. These settings have reduced the need for regular computer users to access the BIOS or CMOS setup. Even with these advancements in modern operating systems, there is still an occasional need to access the BIOS setup.
Unfortunately, the BIOS is essentially a pre-boot environment, so you can't access directly once the BIOS has handed over control to the operating system. This means that you cannot access the BIOS setup directly within Windows.
There are also many options used to Enter the BIOS setup. These options are dependent on your computer manufacturer, age of your computer, among others. On older machines which often take time to boot up, it is common practice to just press the F1 or F2 keys immediately after you power on your computer to access the BIOS setup.
However, this process is a little too slow for modern computers. Modern computers are so quick; they are able to load the OS incredibly fast. This implies that you might not be able to command it, in time, to listen to you pressing F1, F2, or any Key Press at startup. For those of you in this category, here is a more straightforward way designed by Windows 10 to help you access the BIOS setup of your computer.
Relatively newer machines have other more straightforward methods of accessing the BIOS setup. For instance, on a modern computer running Windows 10, you can access the BIOS setup right from your operating system. Here is how you go about it:
Windows will give you access to the UEFI settings. You can use this window to alter the basic settings in the BIOS setup.
UEFI is short for Unified Extensible Firmware Interface. It primarily facilitates the interaction between a computer's OS and its firmware. In the recent past, Intel Corporation announced plans to do away with BIOS and completely replace it with UEFI. This is per their agreement with other Industry players like AMD and Microsoft. The UEFI will be a standard software that cuts across the industry and is managed by an independent forum. Both BIOS and UEFI start immediately you boot up your personal computer. They are responsible for handling all computer processes before your OS takes over. UEFI offers more advanced options compared to BIOS. For you to switch from BIOS to UEFI, your only option is to purchase modern hardware that is compatible with UEFI. However, many UEFI offers some level of BIOS emulation that allows you to run older OSs that expect BIOS. This feature is called backward compatibility.
Generally, UEFI offers a wide range of improvements from the traditional BIOS. The firmware is capable of booting from large memory drives – 2 TB and even more. This is possible because, unlike BIOS that uses MBR (Master Boot Record) partitioning scheme, UEFI uses the GPT (GUID Partitioning Table) partitioning scheme.
UEFI also has more address spaces than BIOS. This simply translates to a relatively faster booting process. In some versions, it also offers more visually appealing settings screens than the BIOS, which ordinarily appears in plain text mode.
However, the UEFI is not merely a BIOS replacement with a sleeker appearance. It is technically an entire OS that oversees the overall functioning of the PC’s firmware during the booting process. It can be loaded from a hard drive or flash memory attached to the motherboard. Different computers display different features and interfaces of the UEFI, depending on the PC's manufacturer.
CMOS should not be used interchangeably with BIOS. It is sometimes referred to as Non- Volatile RAM (NVRAM) or Real-Time Clock (RTC). CMOS stands for Complementary Metal-Oxide Semiconductor. CMOS is a semiconductor chip attached to the motherboard, and it is battery powered. It is used to store vital information about the computer, such as hardware settings, date, and time settings, among others.
There is a special CMOS battery that powers its operation. Although the lifetime of the CMOS battery is dependent on many environmental and usage factors, it's standard lifetime is approximately ten years. Is your computer unable to remember the correct date and time after it is shut down? This is a common indicator that the CMOS battery is starting to fail. Other signs of CMOS battery failures may be shown on your screen during the booting process. If you see an error message such as CMOS Battery Failure, CMOS Checksum Error, CMOS Read Error, or System Battery Voltage low, chances are your CMOS battery has a problem.
In essence, the BIOS needs the CMOS to save all the changes you make to the computer system. While working on the BIOS or CMOS setup, be very careful. Any incorrect settings may prevent your PC from booting again. Once changes are made, you can either discard, restore default settings or save the changes and exit.
There are so many different procedures to use today to access the BIOS or CMOS setup. Although some of these methods have been mentioned, this article does not exhaust all the possibilities. The BIOS or CMOS setup is pre-boot systems that control the computer immediately before control is handed to the OS. It is important to note that BIOS and CMOS cannot be used interchangeably since they are not similar. However, it is acceptable to use the terms BIOS setup and CMOS setup interchangeably.