Welcome to the MacNN Forums.

pb_soon · Oct 13, 2003, 08:38 AM

I'm currently a Windows notebook user (but very very soon switching to PB15") and one function that I do like is the "hibernate" mode. Does OS X and Powerbooks have such a function. I'm not sure what the "sleep" mode precisely means in OS X, but in Windows, this is different to hibernate. Hibernate actually powers down the machine, whereas sleep will still chew up battery life (very slowly of course). If Jaguar doesn't have hibernate, does anyone know if Panther will have such a functionality?

bonk · Oct 13, 2003, 09:07 AM

I didn't think hybernate fully powered down the machine ... I could be wrong though.

Sleep is what you want to do. It turns off just about everything, but keeps power to the ram so you don't lose what was open. It only consumes about 1% an hour roughly.

michael_on_mac · Oct 13, 2003, 09:46 AM

Originally posted by bonk:
I didn't think hybernate fully powered down the machine ... I could be wrong though.

yepp.

Sleep is what you want to do. It turns off just about everything, but keeps power to the ram so you don't lose what was open. It only consumes about 1% an hour roughly.

Hibernation saves the RAM state to disk, thus consuming no power at all (unless you have some wake-on-x features running).

It's actually quite a difference. BTW, hibernation can be pretty fast if you have only little RAM allocated (and use WXP instead of W2k).

I wish Apple had this - however I know no un*xoid OS that has this feature.

Best,
Michael.

pptiger · Oct 13, 2003, 09:48 AM

yeah, I'd love to have this feature. The startup process is too long.

LfGrdMike · Oct 13, 2003, 09:59 AM

Wait isn't sleep the same thing as hybernation. Apple just named it different.

Drakino · Oct 13, 2003, 10:50 AM

Being a recent Windows switcher, I can understand your concern about sleep. Sleep mode on the Windows side is unreliable, and takes a while to come out of. Almost to the point where hibernation is better, even if it does take slightly longer. I never use sleep on a Windows PC.

But with my Powerbook, I have put it it sleep frequently,and have never had a problem with it waking up. It always takes less then 2 seconds, and now due to this, I rarley power it off completly. Even when a low battery sleep mode starts, you can let it sleep for at least 12 hours before needing to plug it in again.

pptiger · Oct 13, 2003, 10:56 AM

Originally posted by LfGrdMike:
Wait isn't sleep the same thing as hybernation. Apple just named it different.

I think they are different. While your machine is sleeping, it still consumes power (should be just a little). In the case of hybernation, first the system will write all the information stored in RAM onto harddisk, then completely shut down the computer. Next time when you restart, it will restore all the information from the harddisk.

nagromme · Oct 13, 2003, 11:31 AM

Apple was at one point working on this--"Save and Sleep" it was called, I think?

It's not a current feature, nor in Panther AFIAK, but maybe someday.

As people say, though, Sleep works great on Macs, and a PowerBook can sleep for days in my experience without running the battery down. Sleep powers only the RAM, to my knowledge. Well... and the pulsing Sleep light!

PowerBooks Sleep just by closing the lid--not button to push, no command to click. They wake instantly when you open the lid. That's so nice that I don't think I'd want even a small additional delay from hibernate.

But I DO agree Apple should offer hibernate as an option. I hope they do--no matter what they call it.

dialo · Oct 13, 2003, 12:06 PM

My experience is that hybernate takes a second to come out of while an apple comes out of sleep immediately. I have no problem with sleep on mac.

Luca Rescigno · Oct 13, 2003, 02:46 PM

The only use I could see for a hibernation mode would be for swapping batteries. My dad's 550 MHz PowerBook stays sleeping for a while (more than a minute) even if the battery is removed because it has a PRAM battery. However, I think Apple has removed the PRAM battery from recent PowerBooks (true? if so, why?), and no iBooks have PRAM batteries.

In my experience, hibernation is just as slow as shutting down and restarting, except that you don't need to relaunch all your applications.

nagromme · 03:04 PM

I don't think PRAM is the issue--Parameter RAM is stored, even when power is cut, on ALL Macs. Otherwise your clock would be lost when the power goes out.

The issue is a secondary battery that can power the computer (not just PRAM) while asleep--for just a few minutes. Long enough to swap batteries without shutting down.

iBooks lack that secondary battery (cost/space?). So do 12" PowerBooks. But all other PowerBooks DO still have that! You CAN swap batteries without shutting down.

Luca Rescigno · Oct 13, 2003, 04:06 PM

Originally posted by nagromme:
iBooks lack that secondary battery (cost/space?).

Probably product differentiation. The only advantage is if it really does a nasty lock-up, you can easily reset it by just pulling the battery. That happened on my dad's PowerBook once, and I had to find the PMU reset button on the back after pulling the battery didn't work.

Anyway, thanks for clearing that up.

pb_soon · Oct 14, 2003, 06:59 AM

Thanks all for your replies. Both sleep and hibernation in WinXP is not that reliable anyhow ... I've come across a few issues with wireless connection when waking from sleep or rebooting from hibernation.

From the replies, the Mac sleep feature appears to be pretty good and reliable.

Just one further question, if you leave the PB in sleep mode for a very long period of time (e.g. you forgot you had it in sleep mode), and the battery reaches a critically low level, will the OS do some sort of shutdown automatically? Or will it just go until the battery is totally flat and hence halt the OS?

nagromme · Oct 14, 2003, 11:29 AM

If a PowerBook in sleep runs down the main battery (battery light flashes in warning) and secondary battery too, it has no power to wake and start saving things to HD. It's just like pulling the power plug on a desktop--which OS X can recover from just fine, but it's not good practice. (Obviously, save your documents before abandoning your 'Book for days!)

The general estimate I keep hearing is a loss of 1% per hour while asleep. So around 100 hours of sleep time, or about 4 days. That has to vary a lot I'd say, so my recommendation: cut that number in half and take no chances. If you don't plan to use your PowerBook for two whole days (what's gotten into you!?) then just shut it down. Li batteries last longer if you don't drain them needlessly anyway.

You probably won't forget it's asleep for long: a light on the latch button pulses to remind you it's sleeping.

pbinNov · Oct 14, 2003, 11:54 AM

The one featue I like about my dell inspiron is that I can run an MP3 player and close the lid while the music plays on--- without an external keyboard or anything. Can a pb do this- play music in clamshell mode, without going to sleep?

aapljack · Oct 14, 2003, 12:07 PM

pbinNov: That sounds more like a job for an ipod instead of a closed Powerbook. Plus, wouldn't the speakers be muffled if the 'book was closed?

-b