I have the light on my keyboard, I have the key that toggles it, but I never use it so I programmed it to open up my web browser. Does anybody use it, or even know what it does?
It exists so that people can reprogram it without feeling like they’ve lost a functional key.
So what does the “Scroll Lock” button actually do? (I’m serious: I have no idea, and I can’t find anything about it in any of my computer books.)
For that matter, what does the button that says “PrtSc” and “SysRq” do? And does the “pause” button actually pause anything? How can you tell? It could be pausing something, or it might just be not doing anything at all.
I know what “PrtSc” means. It’s “Print Screen.” I know this from experience. I was in a computer class once (on some really old IBMs with only two colors) and was playing around with the Caps Lock, Num Lock and Scoll Lock lights, and I accidentally hit Print Screen. Without realizing what was going on and wondering why the Scroll Lock light wouldn’t light up, I hit it repeatedly. About 50 copies of my screen were printed and the teacher was furious. I was never caught.
Yes, the pause button used to work. It was nice to have a single dedicated button that would pause any program or game.
Then, of course, Microsoft made it not work any more.
IIRC, I used to use the scroll lock key when I used to play with DOS - if you’d bring up a large directory it would scroll too quickly to actually read; the scroll lock key would stop and start it. [sub]I think that’s what I used, but it’s been years since I did DOS stuff, and I haven’t really done computer stuff since, so…Maybe it was the pause and break key?[/sub]
As for the print screen key…
Well, never mind. It’s not working here at home (prolly cos my keyboards partially broken), but at work I can use the print screen key to ‘take a picture’ of whatever’s on my screen, then paste that document into Paint or Word or Photoshop or whatever. Quite useful with what I do.
I think Scroll Lock was equivalent to the /P swithc in a DOS listing. My computer teacher in grad school had written a routine that made it actually work.
PAUSE still pauses DOOM and DOOM II. 
At least Printe Screen remains damn handy–I use it all the time. Under windows, though, it just snaps a screenshot of whatever’s on the screen and holds it in the clipboard, so long as whatever program you’re using isn’t writing directly to video memory (e.g. realplayer, dvd playback, most games, and so on).
Windows key + Print Screen gets you to the System Control Panel in Windows 95/98.
I use Print Screen all the time for making screen shots of error messages and other fun stuff, but that’s about it.
Corr
SysRq FAQ I think the SysRq key may be vestigial on the PC (basically a throwback to the 3270 that was never removed). Maybe some mainframer will come in and answer this but I think it bounces your LU or termID on the mainframe.
Hitting the Scroll Lock key twice plus the computer number is the default for changing machines on a KVM switch, but that’s just a key reprogram.
Pause still works in some games as does Print Screen.
Scroll Lock can be application-specific. In Microsoft Excel, for example, it just anchors the cursor in the current cell and allows you to navigate around the spreadsheet. For this purpose it’s pretty much useless to me since if I am moving around in a spreadsheet I want the cursor to be there with me, too. In Word it doesn’t seem to do anything at all.
That was indeed the break key. The name of the scroll lock key makes it sound like it would do that, but it doesn’t.
In applications that support the key, it changes the behaviour of the arrow and pgup/pgdn keys so that they scroll the window without moving the cursor.
Nononono, the break key didn’t pause stuff, it stopped them. Like a Ctrl-C or Esc key.
Or at least that’s what it did the last time I used it…
Yep, I used it within the past week. Scroll lock still has its original purpose in the Linux console, which is to freeze the output of the screen for as long as the lock is toggled. It helps when you have a lot of text scrolling by at a speed too fast to read, such as when the system is booting. I remember using the Pause key for the same purpose back (way back) when I did GWBASIC programming in DOS. Incidentally, there’s a debugging option in the Linux kernel that lets you use the alt-SysRq combination to view registers, sync disks, and that sort of thing. So these keys can be mapped to do whatever a programmer wants, but for the most part they’re an anachronism.
I recently had to trash my setup of Agent when it started behaving oddly. It took me an inordinate amount of time to discover that the Scroll Lock had become engaged somehow, and would not disengage. Yes, it did something scrolly locky, not that I could figure out how it worked (I can’t really even describe what it did) but it apparently does something that might be useful to someone. But for gods sake DON’T TRY hitting scroll lock in Agent, I couldn’t find any way to disengage it without reinstallation.
Some quick notes:[ul][]Scroll Lock is the default key for some Belkin KVM switches. Other manufacturers, and even other Belkin KVM switches, sometimes use other keys[]The Pause key will pause any BIOS driven I/O, including the power-on self test (POST) procedure before the OS boots (useful if you need to catch the BIOS initialization messages that flash by too quickly on a modern machine)[]the Windows console will also honour the Pause key (but you have to hit a different key to re-start the output)[]Prnt Scrn is used by Windows to capture to the clipboard. Prnt Scrn by itself captures the entire screen as a bitmap to the clipboard; Alt+Prnt Scrn captures just the window that currently has focus.[/ul]It worries me that I know that.
The DOS version of Sega’s Joe Montana Football allowed the use of the Scroll Lock to pause the timer in the playbook screens so that the person playing wouldn’t be charged a delay of game when trying to decide which play to call.