Alain;
From
http://www.straightdope.com/mailbag/mscrolllock.html
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.
)