[ltp] the purpose or advantage of suspend and hibernation

Theodore Ts'o linux-thinkpad@linux-thinkpad.org
Wed, 19 Nov 2003 09:36:14 -0500

On Wed, Nov 19, 2003 at 01:42:44PM +0000, Ross Burton wrote:
> On Wed, 2003-11-19 at 13:35, Dennis D. Jensen wrote:
> > Why not just shutdown and boot again when needed? It
> > doesn't take _that_ long, unless of course you run a
> > fashionable GUI Desktop (I don't).
> Suspending and unsuspending takes about 4 seconds, shutting down and
> rebooting takes a lot more than that.  With suspend I can shut the case
> of my laptop when the train pulls into a station, and throw it in my
> bag.  When I get back on the train/in the office/whatever, I just open
> the case and by the time I've got my hands on the keyboard, everything
> is exactly as it was.

Absolutely.  That being said, though, I haven't seen the point of
suspend to disk, versus suspend-to-memory.  It doesn't take *that*
much power to keep the memory refresh circuits going, especially when
you have to compare it with the amount of juice to write a heck of a
lot of data to disk.  Suspend to disk also takes a lot longer than a

Fortunately, while hibernation (suspend-to-disk) doesn't seem to work
for me with my T40, suspend-to-memory works fine, as long as I'm using
APM and not ACPI.  It's annoying that I can't get the exact discharge
rate of the batteries like I could with ACPI, but suspend-to-memory is
infinitely more important.

						- Ted