Scroll Lock

Source: Wikipedia, the free encyclopedia.

IBM Model M keyboard
.

Scroll Lock or ScrLk

computer keyboards. Depending on the operating system, it may be used for different purposes, and applications may assign functions to the key or change their behavior depending on its toggling state.[4][5]
The key is not frequently used, and therefore some reduced or specialized keyboards lack Scroll Lock altogether.

Pressing Ctrl+Scroll Lock performs the same function as pressing Ctrl+Pause/Break. This behavior is a remnant of the original

Pause/Break
key. Instead, they assigned the Pause function to Ctrl+Num Lock and the Break function to Ctrl+Scroll Lock.

Function

Window scrolling

The Scroll Lock key is meant to lock all scrolling techniques and is a vestige of the original

cursor.[4][5] 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 rare. Modern programs honoring this behavior include

IBM Lotus Notes, Forté Agent, Renoise, Cakewalk by BandLab, and LibreOffice Calc
.

Some text editors (such as

Microsoft Visual Studio) exhibit similar behavior when the arrow keys are used with Ctrl
pressed.

Most GUI environments neglect Scroll Lock, which means scrolling must be accomplished with a mouse, using means such as scrollbars or scroll wheels, or an "autoscroll" feature activated by the middle mouse button (which may be part of the scroll wheel). In some instances, Ctrl+⇧ Shift in conjunction with the arrow keys can enable scrolling.

Some web browsers including

caret browsing
mode which can be toggled by F7. While the window scrolling behavior with caret navigation disabled (the default) is similar to that suggested for Scroll Lock, enabling caret navigation will enable a cursor scrolling behavior as if Scroll Lock were disabled.

Console scrolling

Pressing the Scroll Lock key in the

booting up (provided the keyboard driver
has already been loaded). Unless configured otherwise or in raw mode, Ctrl+S (DC3 in ASCII) and Ctrl+Q (DC1 in ASCII) can be used instead of Scroll Lock in Unix-like systems to freeze and unfreeze the tty output respectively.

This behavior emulates the Hold Screen key or similar flow control mechanisms on computer terminal hardware.

The behavior should be distinguished from pressing the

Pause key during POST or under DOS
, which, by default, has the effect of temporarily halting the running process.

On the FreeBSD system console, the Scroll Lock key not only pauses output, but additionally enables scrolling: after pressing Scroll Lock, one can use Page Up and Page Down to scroll up or down. Pressing Scroll Lock again disables this mode and moves back to the bottom of the output. The Linux console implemented this behaviour by using ⇧ Shift+Page Up and ⇧ Shift+Page Down, not requiring Scroll Lock to be active; this behavior has been removed due to a vulnerability (CVE-2020-14390).[8] The NetBSD console can be scrolled either with ⇧ Shift+Page Up/ ⇧ Shift+Page Down or by pressing Scroll Lock then Page Up/Page Down .

Boot diagnostics

In

REAL/32, activating Scroll Lock during boot will always enter a special diagnostic mode, where the operating system and loaded device drivers will display detailed status and debugging information about themselves and their interaction with the operating system, sometimes up to several screenfulls per loaded driver.[9] Automatic scrolling is suspended for as long as Scroll Lock remains activated.[10]

TRACE=ON|OFF) and F7/F8 single-stepping modes for as long as Scroll Lock is active.[9]

Debugging

In the

Blue Screen of Death.[11][12]

In

6.0
, Ctrl+Pause/Break pauses the running program in the integrated development environment, as does its alias Ctrl+Scroll Lock.

Copy and paste

In conjunction with the alternative DOS keyboard and console drivers FreeKEYB and K3PLUS, Scroll Lock also serves as part of a

scrap macro. Since this is an integral part of these keyboard drivers, it is fully transparent to running software and therefore works with virtually any DOS program, including at the command prompt, temporary shelled programs, and task switchers.[13][14][15]

Other uses

PC Magazine asked an executive of keyboard manufacturer Key Tronic about the key's purpose in a 1983 interview, he replied "I don't know, but we put it on ours, too."[16]

The indicator light is sometimes used for other purposes such as a

Linux distributions or other applications,[19]
because doing so is less likely to cause problems than manipulating other keys/lights.

Keyboard, video, mouse switches (KVM) often use the Scroll Lock key on the keyboard connected to the KVM switch for selecting between computers. On KVM switches with On-screen display (OSD), a "double click" of the Scroll Lock key often brings up the OSD, allowing the user to select the desired computer from a list or access the configuration menu of the KVM. Some models, especially those without an OSD, switch to the input corresponding to the number key pressed after Scroll Lock, or in the case of some two-port switches, the up and down arrow keys. Simple models with only two or four inputs may immediately switch to the next input following a double press of the Scroll Lock key.

Scroll Lock on keyboards without a Scroll Lock key

Laptops and keyboards without a physical Scroll Lock key[20] may have a second function on another key that acts as if a Scroll Lock key is activated.

Some common methods are:

  • Fn+S or Fn+F6 on certain Dell laptops.[21]
  • Fn+C or Fn+K on certain Lenovo laptops.
  • Fn+C on certain HP laptops.
  • Fn+F11 on Windows.

Another way to press Scroll Lock is to use an on-screen keyboard. In Windows 8 and later versions, it can be found in the "Windows Ease of Access" program group. This will provide access to an emulation of a standard 101/102-key keyboard.[22]

See also

References

  1. ^ "Turn off Scroll Lock - Microsoft Support". support.microsoft.com.
  2. ^ Graphic is seen enclosed in rounded rectangle on scroll lock key in photograph in "What Is Scroll Lock Key? [How to Turn It Off] - Alvaro Trigo's Blog". 2022-04-16.
  3. ^ Graphic is seen enclosed in rounded rectangle on scroll lock key in photograph in Makvana, Mahesh (2022-08-13). "How to Turn Scroll Lock Off (or On) in Microsoft Excel". How-To Geek.
  4. ^ a b IBM: IBM PC User Manual. Page 5-20: "This key is interpreted by appropriate application programs as indicating that the use of the cursor-control keys should cause windowing over the text rather than cursor movement. Pressing the Scroll Lock key a second time reverses the action. The keyboard routine simply records the current shift state of the Scroll Lock key. It is the responsibility of the system or application program to perform the function."
  5. ^
    IBM Corporation
    . March 1983.
  6. ^ "Accessibility limitations in Project". www.Microsoft.com.
  7. ^ "Toolbar". www.image-line.com. Retrieved 2023-09-08.
  8. ^ "Linux 5.9 Dropping Soft Scrollback Support From FB + VGA Console Code". www.phoronix.com. Retrieved 2022-12-22.
  9. ^ a b c d Paul, Matthias R. (1997-10-02). "Caldera OpenDOS 7.01/7.02 Update Alpha 3 IBMBIO.COM README.TXT". Archived from the original on 2003-10-04. Retrieved 2009-03-29. [1]
  10. Concurrent Controls, Inc.
    (CCI). 1997-02-10. HELP.HLP.
  11. Microsoft Corporation
    . Retrieved 2011-09-25.
  12. ^ "Sean Daily, Tricks & Traps: Daily Answers". November 2000.
  13. ^ Frinke, Axel C.; Paul, Matthias R. (1995-05-10) [1991], K3PLUS v6 - Der ultimative Ersatz für den DOS-Standard-Tastaturtreiber KEYB GR (User Manual) (in German) (r49-v6.21 ed.) (NB. K3PLUS was an extended keyboard driver for DOS widely distributed in Germany at its time, with adaptations to a handful of other European languages available. It did support a sub-set of the FreeKEYB features already. K3PLUS.DOC is part of the K3P621P2.ZIP distribution package.)
  14. country codes
    .)
  15. ^ Paul, Matthias R.; Frinke, Axel C. (2006-01-16), FreeKEYB - Advanced international DOS keyboard and console driver (User Manual) (v7 preliminary ed.)
  16. PC Magazine
    : 347. Retrieved 2013-10-21.
  17. ^ 11.JPG (การใช้งาน Ubuntu | SAMUTSAKHON FOUNDATION)
  18. ^ "Keyboard Layout Options, Keyboard Preferences". Desktop User Guide - GNOME Library.
  19. ^ "Illuminated Keyboard Hack". Kipkay (via Instructables). 2008-05-30. Retrieved 2011-07-25. Using the Scroll Lock key for illuminating your keyboard
  20. ^ "Keyboard — General Discussion". Logitech. 2008-08-28. Retrieved 2008-11-26. This keyboard does not have a Scroll Lock key
  21. ^ "Dell Inspiron 17 specification" (PDF).
  22. ^ "Use the On-Screen Keyboard (OSK) to type".
IBM PC keyboard (Windows, ANSI US layout)
Esc F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 PrtScn/
SysRq 		Scroll
Lock 		Pause/
Break
TildeExclamation markAt signNumber signDollar signPercent signCaretAmpersandAsteriskParenthesisParenthesisUnderscorePlus signBackspaceBacktick1 (number)2 (number)3 (number)4 (number)5 (number)6 (number)7 (number)8 (number)9 (number)0Hyphen-minusEquals signBackspaceTab keyQWERTYUIOPCurly bracketCurly bracketVertical barTab keyQWERTYUIOPSquare bracketSquare bracketBackslashCaps lockASDFGHJKLColon (punctuation)Quotation markEnter keyCaps lockASDFGHJKLSemicolonApostropheEnter keyShift keyZXCVBNMBracketBracketQuestion markShift keyShift keyZXCVBNMComma (punctuation)Full stopSlash (punctuation)Shift keyControl keyWindows keyAlt keySpace barAlt keythumbMenu keyControl key
 Insert Home PgUp
Num
Lock
 ∕ ∗
−
Delete End PgDn 7 8 9
+
4 5 6
↑ 1 2 3 Enter
← ↓ →    0
   Ins 		 . 
Del
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