In a particularly nerdy Facebook status update I mentioned that I had flashed my BIOS. One of my friends asked what the BIOS is.

My question is: How do you explain what the BIOS is and does to a layperson? (Hint: "The BIOS is the basic input/output system" is not going to be accepted as the answer.)

(Of course, the real question is "does she like me?", but I'm not sure there's a site for this :-p )

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    She really wants to know what body part the BIOS is. She must like you.
    – simplr
    Commented Mar 27, 2010 at 20:05

6 Answers 6


Usually when I try to explain a technical concept to a non-techie, I revert to Simple English Wikipedia.

"BIOS, in computing, stands for Basic Input/Output System. The BIOS is a computer program embedded on a chip on a computer's motherboard that recognizes and controls various devices that make up the computer. The purpose of the BIOS is to make sure all the things plugged into the computer can work properly"

  • 4
    -1 My grandma wouldn’t understand your definition. She does not understand such things as „embedded”, „chip” and „motherboard”.
    – kinokijuf
    Commented Feb 29, 2012 at 14:34
  • 1
    @kinokijuf: define:embedded, define:chip, define:motherboard Commented Feb 29, 2012 at 22:39
  • @TomWijsman Rephrase your question.
    – kinokijuf
    Commented Mar 1, 2012 at 12:32
  • BTW, I upvoted the starter motor analogy.
    – kinokijuf
    Commented Mar 1, 2012 at 12:32
  • 1
    @kinokijuf: Rephrase what question? The starter motor analogy is highly inaccurate; everyone knows that the BIOS starts the computer, however what is being asked here is explaining what the BIOS is which takes a stup further than saying starter motor... Commented Mar 1, 2012 at 13:14

Okay, the best way to explain it to her is to buy a new upgrade part for your computer, then invite her over to help you install it. Then you'll be able to show her all of the parts inside a PC, show her how to access the BIOS, explain what it does, and maybe order some Chinese food. If you do this right, she'll spend a couple of hours with you, and you should be able to upgrade to a second date without too much effort.

Of course, if she says she's not interested in helping you, you'll at least be able to console yourself with your new PC upgrade.

It's a win-win situation. :-)

  • 2
    a creative answer! +1 :)
    – studiohack
    Commented Mar 27, 2010 at 21:46

For short definitions, I usually use the first sentence or two on Whatis:

BIOS (basic input/output system) is the program a personal computer's microprocessor uses to get the computer system started after you turn it on.


Here's the explanation - I would just say what it does in simple terms - Substitute your operating system of choice for Windows here:

The BIOS has control of the computer when it is first turned on before Windows is loaded. It's job is to initialize the motherboard (i.e. DRAM), perform a few system checks, and then load Windows off of something. It also tells Windows some things about the computer its running on, and is also involved when the system goes to sleep or is powered off.

Sorry, @Kevin Y, but I disagree with you. "...recognizes and controls various devices that make up the computer," to me anyway, describes more of what the operating system is supposed to do - the BIOS, for example, won't really control PCI addon hardware other than possibly the ability to make it invisible to the operating system.

Don't think it's really necessary to explain it's historical relationship to DOS or anything to a layperson.


BIOS is the program that allows the computer to perform its most basic operations, thus permitting the computer to load other programs, and most importantly the operating system, from it's connected devices, such as the hard disk, a USB key, the CDROM...etc


This is what I say.... If your car is the computer then you are the BIOS. You unlock the door adjust the mirrors push in the clutch put your foot on the break turn the ignition key and the car starts. Now its running.

  • Once you start to drive, are you still the BIOS?
    – fixer1234
    Commented Aug 13, 2015 at 20:44
  • That's a very confusing analogy. What happens after the car starts? Commented Aug 13, 2015 at 22:31
  • I use this analogy for people that don't understand anything about computers. Its hard to explain something using more terms they dont understand. If anyone can build on this analogy or has a better one please share. After all i found this page because i couldnt think of a better way to explain Bios to my 86yr old great aunt.
    – saben
    Commented Aug 15, 2015 at 18:52
  • i guess i could have said its what makes your computer go. ug ug
    – saben
    Commented Aug 15, 2015 at 18:56

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