On 23/03/15 14:16, Matti Nykyri wrote:
On Mar 23, 2015, at 14:13, Nikos Chantziaras <rea...@gmail.com> wrote:
On 23/03/15 11:46, Peter Humphrey wrote:
The consensus seems to be that there's no point in trying to prevent a user
from rebooting the machine, and I'm happy to go along with that.
The remaining question is: why is the user not allowed to halt it?
Because there's no keyboard shortcut for halt. Only for reboot :-)
Well you can set init to run halt on ctrl-alt-up arrow -keypress.
This is mostly about standard expectations though. No one expects to
halt the machine with the vulcan pinch. You press the power button for
that, which does a safe shutdown in the majority of setups (unless you
have all power management features disabled.)
Nowadays, only the reset button is a source of evil, as it's not handled
by ACPI (or other power management mechanisms). It really is hardwired
into resetting the the mainboard/cpu.
So:
Rebooting with ctrl+alt+del: safe
Halting by pressing the machine's power button: safe
Pressing the machine's reset button: Ouch!
Of course, back in the bad old days, the power button would simply cut
power. There was no ACPI or anything equivalent. But still, even then,
there was no keyboard shortcut for "halt" anyway, so people weren't
expecting to be able to safely halt a machine without root access. The
ability to reboot safely, on the other hand, was always expected.
