keyboard indicator lights

[metman]

On most computer keyboards, there are 3 indicator lights near the upper right hand side of the keyboard.

Left to right are; num lock, caps lock, and ???

What is the one on the right?

I had and Internet glitch while this light was on (I must have touched some key inadvertently). So I closed all programs and rebooted. The light and the glitch were gone.

Which key(s) make that light come on?

 

[IRstuff]

Scroll Lock, on mine

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[genomon]

A brief history here:

http://www.straightdope.com/columns/read/2125/whats-the-scroll-lock-key-on-my-computer-for

 

[metman]

Thank you IRstuff & genomon.

 

[MikeHalloran]

Geeky explanation: No key directly controls any of the lamps on the keyboard. Keys and lamps are controlled by a microcontroller (or part of an LSI) that in turn communicates with the BIOS, that in turn communicates with the OS.

I think there are more than a couple of ways by which a transient program can gain control of the lamps and use them for its own purposes. ... but usually the Scroll Lock key causes, however indirectly, a keycode to be sent to the CPU on depression or release of the key, and the lamp to change state, in response to an errant touch by some portion of the anatomy of the person out front.




Mike Halloran
Pembroke Pines, FL, USA

 

[genomon]

If you really want to get into it, try this:

http://www.beyondlogic.org/keyboard/keybrd.htm