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I thought OS needed drivers to communicate with certain device.

But it doesn't need drivers for keyboard, mouse, computer display etc.

Why? How does it know what kind of keyboard or mouse i have?

What makes it work with any hardware of these types?

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Your question is predicated on a falsehood. Windows NT does need drivers for keyboard, mouse, display adapter, and so forth; and one can find them in use on pretty much any Windows NT installation. So asking why Windows doesn't need the likes of kbdclass, mouclass, i8042prt, and so forth, and how it manages to work without them, when it actually does require them and will not drive the devices without them, simply makes no sense as a question. – JdeBP Nov 7 '11 at 23:54
Windows uses unicorn magic! – surfasb Nov 8 '11 at 9:53
@JdeBP - I'd argue that it's an easy misunderstanding to make (the difference between a driver you have to install and a driver that's already there) so it's actually a very good question. (Obviously, that's why I answered it.) – Shinrai Nov 8 '11 at 15:09
A logical fallacy such as this (It's a loaded question where the implied predicate is outright false.) is the antithesis of a very good question. – JdeBP Nov 19 '11 at 15:11
up vote 7 down vote accepted

Windows (indeed, pretty much any operating system) includes some base level functionality drivers that can handle the vast majority of devices. Unless you have some device that was designed (very poorly) to have nonstandard functionality, the ones that come out of the box tend to do the job. This is all in the interest of ease of use and installation for the standard user, with these sorts of very predictable devices. It doesn't know what kind of keyboard or mouse you have - it doesn't need to.

For most users, this is most obvious with, say, a fancy mouse and keyboard - often you get basic functionality out of the box, but you don't get any of the extra functions until you install the manufacturer's drivers. It's also the reason, for example, that you still get video output (albiet low resolution) even before you install the video drivers - there's a base level driver that's good enough to function.

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+1. Also check out info about the BIOS to find out how Windows knows to load drivers for the basic IO devices: "The BIOS software is built into the PC, and is the first code run by a PC when powered on ('boot firmware'). When the PC starts up, the first job for the BIOS is to initialize and identify system devices such as the video display card, keyboard and mouse, hard disk drive, optical disc drive and other hardware". – Ƭᴇcʜιᴇ007 Nov 7 '11 at 21:56
Additionally, why it works with graphic cards: Every graphics card implements the VGA standard for video output which is very basic. Everyone can talk to VGA devices, you don't have to know any specifics about the device for this. – sinni800 Nov 7 '11 at 22:01
@sinni800 - More detail than I felt was warranted, but exactly - and true for other devices as well. They comply to standards! – Shinrai Nov 7 '11 at 23:09
This is exactly what standards are for! ;) – HaydnWVN Nov 8 '11 at 10:18
I love standards when they WORK – sinni800 Nov 8 '11 at 12:08

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