The Scroll Lock key!
The Scroll Lock key can usually be found directly above the group of keys that contains Insert Home and Page Up keys, nestled in-between the Print Screen/SysRq and Pause/Break keys (which we’ll get to another time).
Now, certainly a key with its own LED light must have some kind of grand function, right? Wrong. The Scroll Lock key is a hold-over from back in the day, where the user would need to modify the behavior of the arrow keys so they could just scroll the contents of a text window instead of moving the cursor. Not very interesting, eh?
Some programs, like MS Excel and Lotus Notes, still make use of the Scroll Lock, but outside of that, and perhaps a few other program-specific functions, it’s rarely used anymore. Some keyboards, like those manufactured by Apple, don’t even have a Scroll Lock key on them.
Now you know!