Actual, useful info in a Slashdot poll
A poll on useless keys on a keyboard shows the usual /. biases, so the Windows key got nominated. Someone actually put up some useful keystrokes using this key:
Win+m minimizes all windows
Win+e opens Explorer
Win+r opens Start|Run… dialog
Win+f opens the Find application
Win+Pause opens Systems Properties
Also, a keystroke dating back to Lotus 1-2-3 days that still works in Excel: scroll-lock being on causes the arrow keys to scroll the spreadsheet, rather than moving the cell.
And this tidbit I found out on my own, but here’s a better explanation of what’s going on:
I actually find Num Lock to be very useful on x86 machines, but not for the originally intended purpose. Num Lock actually causes is a high priority interrupt (second highest, I think), and the system should respond by toggling the LED. Num Lock is then an easy way to tell if the processor has interrupts disabled. If they’re disabled for any significant amount of time, that means the OS has crashed. It’s a really fast way to tell if the system has crashed or only the user interface.
Under Linux, the Alt-SysRQ, if enabled, do these:
b – Reboot hard.
e – send TERM to all processes, but not to init
i – send KILL to all processes, also not to init
k – send KILL to all processes on only the current console
l – send KILL to _all_ processes (init included!)
m – dump memory info to screen
p – dump registers to the screen
s – sync kernel buffers to disk
t – dumps process info to screen
u – remounts root partition read-only
which should get you out of kernel crashes. This is more useful for kernel developers, though.