Scroll Lock

Scroll lock (⇳) is an antiquated keyboard button (often with an associated status light) on some computer keyboards. The key is infrequently used, and therefore some keyboards lack Scroll Lock altogether.

The Scroll Lock key was meant to lock all scrolling techniques, and is a remnant from the original IBM PC keyboard, though it is not used by most modern-day software. In the original design, Scroll Lock was intended to modify the behavior of the arrow keys. When the Scroll Lock mode was on, the arrow keys would scroll the contents of a text window instead of moving the cursor. In this usage, Scroll Lock is a toggling lock key like Num Lock or Caps Lock, which have a state that persists after the key is released.

Today, this particular use of Scroll Lock is not used or is rare. Only very few modern programs still honor this behavior, such as Lotus Notes and Microsoft Excel. Most GUI environments neglect Scroll Lock, which means scrolling must be accomplished with a computer mouse, using means such as scrollbars or scroll wheels. Many common text editors (such as gedit, Notepad++, and Visual Studio) exhibit similar behaviour when arrow keys are used with control key depressed.

Pressing the Scroll Lock key in the Linux console while text is scrolling through the screen can freeze the application generating the output—during the duration of the freeze no further text accumulates in the buffer, but rather the output continues from where it left off after Scroll Lock is released. This allows the user to pause the display and read long messages that scroll through the screen too quickly to read, for example when the system is booting up (provided the keyboard driver has already been loaded).