On 2009-12-26, Winston wrote:

[ ... ]

I learnt that half the time, error indicators are devices used
to steer the user *away* from the issue at hand.

:-)

Rumor has it, there are computers and cars which you *turn off*
by first pressing a "Start" button. (I am not making this up.)

Not just rumor -- though it is not a physical button. It is a
click-on area on the GUI on the screen. Windows started this, and other
systems (including some linux ones) have picked up the same practice.
You click on "START" while it is running, and it gives several choices,
including "shut down" and "reboot". The Mac OS-X doesn't use a "START"
button, but it does offer those choices from the "sleep" button (a new
moon on the Sun keyboard, I don't have a genuine Mac keyboard), along
with "log current user out" so another user can log in.

Quite a few unix systems, as well as the Mac Mini, use the
physical power button to initiate a graceful shutdown -- or if it is
hung and ignoreing that, holding the button for something like five to
fifteen seconds *force* a shutdown. The same is present on my Sun Blade
2000, and several other recent ones. But the first system on which I
saw this was the Tektronix 6130 -- a National Semiconductor 32016 CPU
with BSD unix. I wish the others had added this shortly after then, but
they did not.

On the Sun, the "sleep" key (again, new moon symbol) shuts the
system down while preserving the entire state, so when you power it back
up (with the front panel power button) it brings it up with you still
logged in, and all of your programs still active, including windows on
other systems. But it does bring it up with the screen locked, so you
have to use your password to get in, just in case it happens to get
power back when someone else is nearby and you aren't. :-)

The Sun does have a separate "exit" click-on to log you out, and
shut down the GUI.

Enjoy,
DoN.

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