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What's A 'Scroll Lock' And Why Is It On My Keyboard?

Jeff Bauer writes "Today's article in The Straight Dope explains all the weird keys that come with standard PC keyboards. Now if someone could just explain what the 'Alt Graph' key does on my Sun keyboard, enlightement would be at hand ..."

23 of 866 comments (clear)

  1. Scroll lock is useful in Linux terminals by gotr00t · · Score: 5, Informative
    When using a TTY terminal in Linux, the scroll lock is an extremely useful key so that you can pause the output in order to read it. In most BIOS's, you can also press it to pause the info that it is giving you as well.

    Many people think that scroll lock is now useless, except in Microsoft Excel, but it does have a much more useful purpose, at least in Linux and perhaps BSD.

    1. Re:Scroll lock is useful in Linux terminals by drinkypoo · · Score: 3, Informative
      I have news for you, and its name is ^S and ^Q! Sing it loudly from the mountaintops!

      P.S. this works places other than Unix also.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  2. Alt Graph on Sun-boxen ... by Hektor_Troy · · Score: 5, Informative

    The Danish keymap is the same on all PC's (and Sun Boxen as well), and we need Alt Graph to access the following characters:
    \@${[]}|~?

    Not sure about the US keymap, but I sure as hell wouldn't want to go without Alt Graph.

    --
    We do not live in the 21st century. We live in the 20 second century.
    1. Re:Alt Graph on Sun-boxen ... by NaturePhotog · · Score: 4, Informative

      On keyboards in general, most keys generates two characters. This is fine for English, not using any letters besides A-Z or any accents as far as ASCII is concerned.

      However, for many European languages, there are additional characters, like a+ring (U+0035) in Swedish, and accented characters, like e+acute (U+00E9) in French. Since back in the days of XTs, there were only 83/84 keys to go around, they made some keys produce a third and sometimes fourth character. These were accessed by pressing Ctrl and Alt for the third char and Ctrl, Alt and Shift for the fourth char and then the key.

      At some point, it was (rightfully) decided this was unnecessarily clunky. Keyboard BIOSes/drivers were changed to support the Mac-style input of accent + character to generate that character accented. That still left the 'standard' for older keyboards to be backward compatible with, and other chars that didn't fit that pattern.

      So when the 101/102 key keyboards came out, for European languages that changed the right Alt key to Alt Gr, or alternate graphic. (For some languages it had a different abbreviation, like Alt Car). This allowed typing Alt Gr plus one of the 3- or 4-character keys to access the 3rd (and with Shift, the 4th) character. Still a pain, but less so than a 3 or 4 finger salute to get a single character.

  3. Use for the tilde key by uvsc_wolverine · · Score: 3, Informative

    The tilde still has some limited use in C++ (don't know about other C-based programming languages since I don't know any of the others...yet). It's how you indicate to the compiler that this is the destructor function for programmer-defined class. That way the instructions in the destructor are automatically executed when an object of the class goes out of scope (usually used for returning dynamically allocated memory). Example: MyClass(); //CONstructor ~MyClass(); //DEstructor

    --
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  4. Alt Graph.... by jdreed1024 · · Score: 3, Informative
    Alt Graph is a modifier key, like Shift, Control, Meta, etc. It existed on the PC platform too. If you look at non-US keyboard maps in the old IBM DOS manuals (like version 3.30), you'll see the that one of the "Alt" keys was labelled "AltGr" (guess what the "Gr" is an abbreviation for). You had to use the AltGr key to get things like accents and stuff if you used a non-US code page in DOS.

    ISTR that AltGraph+Help did something on older Sun machines, but I can't recall what.

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  5. Re:Wrong! by Trogre · · Score: 4, Informative

    For example, una says the Macintosh extended keyboards have a scroll lock key. It does not.

    Yes it does. It shares the same keycap as F14.

    --
    "Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
  6. Re:real application! by shird · · Score: 5, Informative

    'clip' is not a program which comes default installed with WinXP. Try it and see.

    You must have it installed from somewhere else, or as part of the admin pack or whatever. Its obvioulsy just a program which puts the stdin input into the clipboard, pretty useful, but not included by default.

    --
    I.O.U One Sig.
  7. Re:real application! by WatertonMan · · Score: 4, Informative

    In OSX it is ls | pbcopy

  8. Re:real application! by rwuest · · Score: 5, Informative

    get xclip http://people.debian.org/~kims/xclip/, install, then

    $ ls | xclip -i

    does what you'd expect.

  9. Xon/Xoff history lesson: blame microsoft by goombah99 · · Score: 5, Informative
    Since everyone hear has totally missed the boat I'll chime in. The concept of a Scoll lock is indeed alive and well today. Try the following on your Unix computer: run some command that spews text to the screen in a terminal window (e.g. fs_usage or du /) now while its scrolling type control-S. it scroll locks. Now type control-Q to resume the text output.

    this dates back to the teletype and is enshrined in the ascii alphabet as Xon and Xoff. Originally it was intended not as a scroll lock but as a way for a teletype or printer to not overflow its fixed hardware buffer. The communication baud rate could easily out pace the tele type printers print speed. when the hardware buffer was nearly full it would send an X-off (contol-s) to the sender to pause its communications. When the buffer was printed the teletype would send a X-on back to the sender to resume spewing.

    There was no need for scoll locking functionality on a teletype printer since you could just hold up the paper and look at it back as many lines as you wanted.

    but when dumb video terminals came along the terminals could print as fast as the data came in the X-on and X-off functions had little use as a communications protocol, but Now they were useful to humans as a scroll lock. they had at most 40 lines of text and once you scrolled off the top of the screen, you lost that line forever. There were no "windows" or "scroll bars". So you had your fingers poised over the contrl-s key to halt the text from flowing off the screen.

    finally along came the PC and Microsoft messed with all the unix converions in their VMS/CPM ripoff called dos: so you could not be sure that control-S would actually work. In part this was because DOS was not really multitasking. programs could take over the OS and capture all the interupts and put hooks directly into the keyboard handler. Since there were no Menus and the "alt" key had not come into its standard defintion yet, the control keys were premium realestate for programs to hook functions into.

    thus there was a need for another semaphore. So things like scroll lock and sysRequest, and print screen got added. So yes virgina you can blame MS for these keys as valuable male breasts or an appendix.

    --
    Some drink at the fountain of knowledge. Others just gargle.
  10. Re:real application! by SEE · · Score: 5, Informative

    Correct. clip isn't built in.

    Clip is one of the utilities from http://www.cmdtools.com/ .

  11. Yes: Screen by marnanel · · Score: 4, Informative

    Well, the clipboard is a property of the environment, rather than the OS. But there's certainly at least one environment that allows this: GNU screen.

    Screen has a concept of a buffer file that can be used to store or load the clipboard. The name of this file is defined in your screenrc, so it can vary from system to system, but it's often called /tmp/screen-xchg or (better for multi-user systems) ~/.screen_exchange. The keystroke ^A< reads this file and ^A> writes it; ^A> will also flash up a message telling you what the name of the file is (for example, Copybuffer written to "/tmp/screen-xchg" ).

    So what you do is:

    $ some-command > ~/.screen_exchange
    ^A< (copybuf)
    screen responds "Slurped 2323 characters into buffer"
    ^A] (paste)

    And there you have it.

    --
    GROGGS: alive and well and living in
  12. Fan of Michael Moorcock I presume? by quinkin · · Score: 3, Informative
    Una Persson??

    Well call me Catherine Cornelius and break out the psychotropic lesbian porn fiction...

    Well it is true to the spirit of Moorcock. Just look at the cover art.

    Ok, so it is a touch off-topic, but I was stunned to see a literary(sic) reference in a /. link

    Q.

    --
    Insert Signature Here
  13. Re:Mad Props by rudedog · · Score: 4, Informative

    If I recall correctly, back in the days of openlook, the props key was used to bring up the properties menu for a window. That's as much as I can remember.

  14. Re:real application! by rolocroz · · Score: 3, Informative

    And, as you might expect, pbpaste lets you access what's currently on the clipboard.

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    I meta-mod all positive moderation Unfair, because it's abuse of the system.

  15. Re:Wrong! by silvaran · · Score: 4, Informative

    It was used to lock the cursor in place, and the up and down arrow keys scrolled the entire screen, leaving the cursor locked.

    I'm not entirely certain what article you thought you read, but according to Una:

    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.

    According to you, it sounds like Una got it right at the start.

    RTFA

  16. Just a thought but... by pr0ntab · · Score: 3, Informative

    I imagine open files are tied to the "true" paths:
    multi(0)disk(0)rdisk(0)partition(1)/window s/system 32/ntoskrnl.exe
    etc, etc, etc...

    The C: drive thingies are just useful for the Win32API, so opening new files off that drive won't work, and explorer will probably fail in mysterious ways later on, if the C: is mentioned anywhere in the registry where it might be used to dynamically load some view or file operation.

    As you might expect, drives letters are just places where to start a mapping to a mounted filesystem (which is internally identified with a GUID, like everything else, the drive letter has no significance). Windows only needs C: to boot and load programs, but if you aren't opening files, you don't need it.

    --
    Fuck Beta. Fuck Dice
  17. Re:SysReq by bccomm · · Score: 3, Informative

    Not to mention the SysRq key still in use on Linux for debugging---if you enable CONFIG_MAGIC_SYSRQ (Linux 2.4) or CONFIG_SYSRQ (Linux 2.6).

    I really doubt that ``it's days are numbered.''

  18. Re:Windows Key by redhog · · Score: 4, Informative

    All the mysterious keys are there for you to remap using xmodmap! And having a spare one left over is allways good if a key fails (as a result of piping tea through yourr keyboard). And of course, the windows-key is in the correct place of a meta key, so you could be a better emacs-user in just minutes! And when talking about SysReq, it really is a request to the system, if you gave Magique SysReq compiled in in your Linux-kernel - then press Alt-SysReq-key where key is b to reboot, s to sync disks and r to remount all disks read-only. And this works even if some user-space program fucks up your screen and keyboard...

    --
    --The knowledge that you are an idiot, is what distinguishes you from one.
  19. Missing some info by Jack+Schitt · · Score: 4, Informative

    The Scroll Lock was also used by a DOS TSR known as ANSI. When loaded, it allowed scrolling of the entire screen history when the Scroll Lock was on. When you dir a huge folder, you could hit scroll lock and use the arrow keys to navigate the entire list of files. More useful than dir /p...

    The Print Screen/SysRq key was used in Dos to send the current screen of text directly to lpt1: (your printer), hence the name "Print Screen". In Windows (all the way back to Windows 3.x), Print Screen executes a screen capture (without the mouse cursor) and puts it on the clipboard. Alt+PrintScreen copies just the current window.

    In addition to what was said in the article about Pause/Break, pressing it _during_ a dir or other scrolling text operation will halt the screen. (This includes during booting before the OS loads.) Press any key to continue.

    As for the `/~ key? Still haven't found a useful function for it other than typing a ` or a ~.

    And the |? That one serves just about the same purpose to me as the "Context Menu" button on many newer keyboards, which is to say, none.

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  20. What's Alt Gr for? by jonbryce · · Score: 4, Informative

    For people who don't speak english, Alt Gr is pretty useful, as it lets you type accented characters. In EU countries, it is also used to let you type the Euro symbol - Alt-Gr+4 on UK and Irish Keyboards, Alt-Gr+E on most others.

  21. Re:real application! by olderchurch · · Score: 3, Informative

    Try irfanview an excellent image viewer, with automatic resize and slideshow!

    --
    Disclaimer: This opinion was created without the use of any facts