A Staff Report from the Straight Dope Science Advisory Board
= What's the "Scroll Lock" key on my computer for? = October 7, 2003 Dear Straight Dope: Why does my computer keyboard have this "Scroll Lock" key that seems to serve no purpose whatsoever? In 15 years I don't remember ever pushing that button. I'm almost scared to touch it - Insanegrey, Lawrence, KS Although your mother told you that there are many things to avoid touching (like downed electric lines, scorpions, and the "naughty place"), don't be afraid to touch the Scroll Lock key. Nothing bad will happen - in fact, probably nothing at all will happen. Once upon a time, however, something did. The Scroll Lock key has appeared on the keyboards of IBM personal computers since the original 83-key PC/XT and the 84-key AT layouts, and remains on the 101-key and greater "enhanced" keyboards currently in use. The Scroll Lock key wasn't on the original Macintosh keyboards but appears on the Mac's "enhanced" keyboard. The main intent of the Scroll Lock key was to allow scrolling of screen text up, down and presumably sideways using the arrow keys in the days before large displays and graphical scroll bars. You can see where this might have been handy in the DOS era, when screen output typically was limited to 80 characters wide by 25 rows deep. For some types of programs, spreadsheets being the obvious example, it's still handy now. In Microsoft Excel, Scroll Lock allows you to scroll a spreadsheet with the arrow keys without moving the active cell pointer from the currently highlighted cell. In Quattro Pro, another spreadsheet program, Scroll Lock works in a similar manner, although in contrast to Excel it's not possible to scroll the active cell pointer completely off the screen. Other programs use Scroll Lock for special functions. It's said (although I haven't personally verified this) that the Linux operating system as well as some early mainframe and minicomputer terminals employed Scroll Lock to stop text from scrolling on your screen in command-line sessions - pausing the scrolling, in effect. The ancient DOS adventure game "Rogue" (one of my all-time favorites) used Scroll Lock to scroll your character's movement through the ASCII dungeons on the display. I'm told some computers in the late 1980s used the Scroll Lock key to halt the scrolling of the boot-up messages that appeared when you started the computer. This last use may be apocryphal, as I could find no examples of computers that displayed this behavior. The point is, Scroll Lock sometimes does something besides make that little light light up.