What does this key do?

Posted by: Rea Maor In: Misc - Saturday, May 26th, 2007

PC users – you use a keyboard every day, but if you took a trivia test about the usage and history of the keys, I’d bet you wouldn’t score 100%! Here, for instance, is a tour of some of the more obscure keys on the 104-key US-English keyboard.

Scroll Lock – This one gets everybody’s attention, because it seems to have been so important at one time that it still gets its own LED. Scroll lock is a hold-over from the ancient computer days, when terminals just printed text. If you viewed a text file that was too big to get all on the screen at once, it would scroll by too fast to read. So you toggle “Scroll Lock” on and read a screen full, unlock the scroll and let a new screen full of text come up, and so on. Today’s terminals print so fast that using scroll lock to catch the text is impossible. This key really is useless today!

Pause/Break – This was either to pause the scrolling of text on the screen in DOS, or to halt execution of a program. This hails all the way back to Commodore computers, which could be programmed in BASIC and then if you ran the program and it did something naughty, you could hit the ‘break’ key to break the program flow.

PrintScreen/ SysRq – The “print screen” was originally to take a screen shot image of the screen, and is still used for this purpose on some PC programs. But the SysRq is obscure! It stands for “system request” and was originally added by IBM, with the purpose of allowing low-level access to the system in VM/370s and MVS. But even this intended purpose was never implemented! Later PC systems have ignored it.

Number Lock – You probably know that the number pad serves a dual purpose, either as a calculator-like entry for numeric data (data-entry workers use this area, because it mimics a ten-key setup), or with the lock off the keys can double as arrow and Home/End/PageUp/PageDown. But what you probably didn’t know is that on some systems it can also be used to control the mouse! This is usually enabled on Unix systems – to see if you have it, hold down “Ctrl-Shift-NumLock” – if it’s available, you’ll hear a low pitch beep, signifying that it’s on. Hitting it again will produce a high pitch beep. While it’s on, use the number pad as an 8-way arrow and see if the mouse pointer moves. “Clicking” in this mode can be accomplished by pressing the number 5 after hitting “/” for left-click, “*” for middle-click, and “-” for right-click!

The “Windows” Key – You probably know that just pressing this by itself pops up the “Start” menu. But most Windows users don’t know what else it can do, for instance in Windows XP:

  • Win+Break (Display the System Properties dialog box)
  • Win+D (Display the desktop)
  • Win+M (Minimize all of the windows)
  • Win+Shift+M (Restore the minimized windows)
  • Win+E (Open My Computer)
  • Win+F (Search for a file or a folder)
  • Win+Ctrl+F (Search for computers)
  • Win+F1 (Display Windows Help)
  • Win+L (Lock the keyboard – will need password to unlock!)
  • Win+R (Open the Run dialog box)
  • Win+U (Open Utility Manager)

Back in the Windows 95/98 days, hitting “Ctrl-Esc” followed by “Alt-minus-C” made the Start menu disappear! Now, Ctrl-Esc just makes the Start menu pop up. Perhaps the most comprehensive list of Windows keyboard shortcuts you can find for today’s systems is here.

Oh, and I don’t have to tell anybody what Alt-F4 does, right?

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