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Re: [LUG] New distro - and logging off

 

On Sun, 18 Nov 2012, Neil Winchurst wrote:

On 18/11/12 14:26, Gordon Henderson wrote:

What I'm suggesting is that you don't bother with all that mouse
faffing, typing, etc. and just push the power button to turn it off.
That's what it's for. If Linux is installed correctly, pushing the power
buton (just a brief push, as as you'd do to turn it on) will send a
signal to Linux and an automatic shutdown will happen.

I mean, really - who actually types halt, shutdown, etc. these days, or
bothers with the faff on going through the menus. If you want to turn
your computer off, then push the power button.

When I want to turn my laptops off, I push the power buton on them. I
never turn my desktop off, so it's not an issue, but if I wanted to, I'd
use the power button on the front.

Gordon

Well, that is something that I have never considered. I have always understood that you should not do that because, when logging off, the computer needs power while it closes down various programs before it is safe to power down. I am sure that I have been told never to just turn off the power. Am I wrong?

Likewise with the laptops used here. First log off via the menus, then close the lid. Am I wrong again?

There is a difference between telling the computer to turn itself off and pulling the plug.

The power button on a modern PC is not connected to the power supply. It is connected to some circuitry on the motherboard which is powered by the power supply even when the PSU is turned off.

This is the +5v "standby" supply and is active when the PC is plugged into the mains (and the pysical switch on the PSU, if fitted, is on) Most motherboards have an LED which will light up when the PC is off, but the PSU is plugged in.

Pushing the power button sends a signal to the operating system is telling the computer to turn off - which it will do a few seconds after you pushed the button once it's done all it's tidying up, disk syncing, etc.. That's been more or less a feature of modern PC hardware since Windows XP. Linux picked up on this very quickly and for the past 10 years or so, I've used the power button to turn a laptop off.

So on a modern (in the last 10 years at least) PC, pushing the power button has had the same effect as using the menus, typing, whatever to power the PC down.

Why not just try it?

If you're concerned, then open a shell and type sync (type it twice if you're overly paranoid), then push the power button.

Don't push and hold it, just push and let go. If you push and hold it for 5 seconds then it will remove power abruptly and not power down properly.

Of-course you might end up doing what my wife did a for a while - push the power button, then close the lid - the lid-close event seemed to override the shutdown sequence and put it in to suspend mode... So open the lid, press a key - it wakes up then promptly shuts down...

Gordon

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