In modern computers, the boot experience tends to be fast and features minimal interruptions.
On older computers, though, branded screens with lots of details were shown.
This is part of the BIOS, only a tiny part.
TheBIOSis the first piece of software run when a computer boots up.
It stood forBasic Input/Output Systemand was invented by IBM in the mid-70s.
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What Does the BIOS Do?
The BIOSs primary responsibility is to locate and execute the boot loader for an operating system.
Before it does that, however, it has other tasks.
In its early forms, this was pretty much all the BIOS did.
In later versions, this was updated to allow the user to choose which gear to boot from.
Later, in the 90s, the BIOS was updated to add a configuration utility.
Newer BIOS versions also support booting from other storage devices such as CD/DVD drives and USB storage devices.
How Is the BIOS Implemented?
This design meant that the BIOS was completely read-only, and configuration prefs needed to be stored elsewhere.
This typically required a removal tool and was not very commonly done.
This was partly due to the difficulty, but the cost and general lack of necessity were also factors.
Tools are sometimes made available by motherboard manufacturers to update the BIOS from within the operating system.
A bad update could leave the BIOS in an unusable state, essentially bricking the computer.
Two solutions were developed to reduce this risk.
A boot lock isnt changed in a BIOS update and verifies the rest of the BIOS is functional.
The other solution was the dual BIOS.
In this case, two copies of the BIOS are included.
The first one can be overwritten.
If the new BIOS fails to load, it switches to the known good secondary BIOS.
The first BIOS virus was called BIOS Meningitis.
It infected hard drives and attempted to avoid antivirus detection but was relatively harmless.
Both of these viruses were released in the 90s and succeeded thanks to a lack of security controls.
Even if it is downloaded from the motherboard manufacturers website.
A virus on your gear may be able to infect it as you download it.
For this reason, its essential to verify the signature of a BIOS update before applying it.
Even that doesnt protect you from a deliberately or accidentally faulty BIOS update from the manufacturer.
Thankfully this risk is relatively easily dealt with by dual BIOS systems.
Conclusion
The BIOS is the Basic Input/Output System.
It was invented and popularised in the 70s and 80s by IBM and its PC line of computers.
It checks the hardware for basic functionality and loads the operating system.
