You may not notice them because you’re used to them, but your computer’s keyboard is host to a variety of weirdo keys. Here’s a sampling.

Escape. The Escape key, or Esc, is used to produce the Escape character. Once upon a time, the Escape character was used to begin something called an escape sequence, or a bunch of special characters typed to control a program, the computer, or some peripheral. Today, escape sequences used only when programming a terminal screen or writing something like a printer driver. Beyond that, the Escape key serves the function of the computer’s universal Cancel button.

Meta. The Meta key is the direct ancestor of the PC’s popular Alt key, which is called the Option key on the Macintosh. On a Sun computer, the Meta key is flagged by a diamond character, ♦. It might also be called the Compose key or, rarely, the Super key. It’s purpose is to allow for special key combinations used to control a program, such as Alt+F to activate the File menu. The Windows key can also be consider a type of Meta key. The Apple / Command / ⌘ key is also a type of Meta key.

Scroll Lock. This isn’t an unusual key, but it’s purpose is often lost. That’s because Scroll Lock isn’t really used by any programs other than a few spreadsheets. In that instance, pressing Scroll Lock causes the arrow keys to move the entire spreadsheet, not just the cell selector. Oddly enough, the key survives on modern keyboards despite it’s scant usage.

SysRq. The SysRq or System Request key is a throwback from the days of OS/2. When IBM designed the PS/2 computers back in 1987, they added the SysRq key as a way to control the operating system, OS/2. It kind of worked like the Windows key does today, but never really caught on. Today the key still exists, but isn’t used. Instead, it shares a subordinate position on the Print Screen key. Speaking of which:

PrtSc. The PrtSc key is the Print Screen key. On some older keyboards, the key even says Print Screen. What it does is the old fashioned screen dump, which originally was an operation that sent all the text on the screen to the printer. (Old computers generally sported some form of screen dump key combination.) Under DOS, PrtSc performed a screen dump. Today, PrtSc in Windows takes a snapshot of the full screen, which is saved in the Windows clipboard.

Fn. The Fn key, which I call the fun key, is found mostly on laptop keyboards. It’s the key you press to access various special keys you get on a full-sized keyboard but which are difficult to fit on a laptop. You can also use the Fn key to access special features, such as dimming the screen, connecting an external monitor, and other goodies.

Alt Gr. You’ve probably not seen this key, unless you have a European keyboard. The AltGr key, also known as Alt Graph, is used to type in special characters found in certain languages. It’s the locale key, which is why you won’t find it on American keyboards. (We’re all local.)

Rubout. I was fascinated by Rubout when I first saw it on a computer terminal about 30 years ago. Of course, Rubout is really another name for the Delete or Backspace key found on every keyboard today. I don’t know why Rubout fell out of favor and was replaced. I suppose it was rubbed out.