SysReq+++What+is+that?

If you look at the keys at the top right-hand of the keyboard, there are three usually labelled Prt Scr Sys Rq, Scroll Lock , Pause Break Now most people are aware what **Prt Scr** stands for as well as **Scroll Lock** and **Pause, Break.** But how many of you have the slightest indication as to what **Sys Req** stands for ? It is an abbreviation for System Request and that really tells you nothing does it? It is a hangover from old IBM computer consoles where at one time the user had to get approval from the main frame computer to proceed with an application etc. If you ask me why it is still printed on modern keyboards I do not have a clue, to my mind it is the result of lazy designers and manufacturers who cannot be bothered to remove the printing instructions from the manufacturing of this key. You will gather that it has no function whatsoever.
 * SysReq What is that? **