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New "Safe Sleep" mode on Mac laptops

updated 01:45 pm EST, Wed November 16, 2005

PowerBook \'Safe Sleep\'

Apple's on older iBooks and PowerBooks, allowing owners of older Mac laptops to take advantage of the feature (at their own risk). Regular sleep mode works by cutting power to components except for the machine's RAM. Because RAM uses so little electricity and has no moving parts, a machine can operate in sleep for a very long time. But if a battery runs out or is removed, the system's suspended state will be lost. The "Safe Sleep" technology works by recording the machine's RAM contents to the hard disk, which is not affected when power is lost. When the power source is returned, the content is transfered back to the RAM, and the user can resume where they left off.

by MacNN Staff

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TheoCryst
Mac Elite

Joined: Nov 2005

-1

11/16, 02:14pm | report spam | close Reply |
sounds familiar...

Yeah, this isn't all that thrilling. Windows has been doing this for years now: its called Hibernate. All the RAM contents are thrown onto the hard drive and power is completely shut down. This sounds to me like a type of smart-hibernate. Starts out in sleep mode, but hibernates if the battery gets low. A nice idea, one I'd love to see on my Windows laptop. But still not all that innovative.

chabig
Addicted to MacNN

Joined: Jun 1999

0

11/16, 02:17pm | report spam | close Reply |
Now instant wake...

Apparently, it takes about 40 seconds to wake up from safe-sleep as opposed to the nearly instant wake from regular sleep.

JoeSlater
Fresh-Faced Recruit

Joined: Nov 2005

0

11/16, 02:19pm | report spam | close Reply |
Doesn't work on TiBooks

This doesn't work on TiBooks. See the reponses at http://www.andrewescobar.com/archive/2005/11/11/how-to-safe-sleep-your-mac/

I found the same to be true on my (disappointedly).

ATPTourFan
Fresh-Faced Recruit

Joined: Apr 2003

0

11/16, 02:21pm | report spam | close Reply |
Back in the day...

Apple had this feature available (for about 5 minutes) in Mac OS 9, but they quickly disabled it because they couldn't get it to work just right.

Anyone remember the "Save RAM contents to Disk" checkbox in the Energy Saver control panel's advanced tab?

It was dimmed out for a while then completely removed in later versions of Mac OS 9.x

nbtsf
Fresh-Faced Recruit

Joined: Oct 2004

0

11/16, 02:31pm | report spam | close Reply |
Pismo had it...

at least in OS 9.x So it seems like they brought it back.

TailsToo
Mac Elite

Joined: Jun 2004

0

11/16, 02:53pm | report spam | close Reply |
Hmm...

Not really sure why I would want to hack my system to make it do this...

JoeSlater
Fresh-Faced Recruit

Joined: Nov 2005

0

11/16, 03:07pm | report spam | close Reply |
Why to do this...

Here's the WHY: Put your powerbook to sleep. Something jars your battery lose, it goes dead, you forget to put another one back in (orjust don'tdo it quickly enough because your kid fell down the stairs (happened to me). When it's completely out of power, it switches to using the safe mode, and will restore from disk instead of being the equivalent of unpluggin your desktop while on.

If this works on desktops (I've heard some), you can move your desktop without rebooting. This can be very useful.

irow82
Fresh-Faced Recruit

Joined: Jun 2004

0

11/16, 04:05pm | report spam | close Reply |
iBook G4

Works well on an early 2004 ibook.

Interlard
Fresh-Faced Recruit

Joined: Oct 2005

0

11/16, 04:17pm | report spam | close Reply |
No reason to hack it in

I don't think it's worth hacking your old PB to make this work.

Who doens't save their documents before sleeping their laptop? It's just a convenience for it not to forget what you were doing if it looses power.

A journaled filing system can't be corrupted so it's not a big deal.

OtisWild
Junior Member

Joined: Feb 2005

0

11/16, 04:43pm | report spam | close Reply |
Multi-stage sleep...

... So did they do this right by keeping the normal sleep (quick sleep/quick wake but throbs the power lamp and drains slowly for RAM) which then goes into hibernate after the battery goes to, like, 5%? With the option to hibernate, like when you press the power button on a Powerbook and the shutdown/reboot/sleep dialog pops up?

Or do you have to choose what level of sleep you want ahead of time, like in Windows?

Drakino
Grizzled Veteran

Joined: Apr 2001

0

11/16, 04:46pm | report spam | close Reply |
Useful for 12 inch PBs

I can see this being real useful for 12 inch Powerbook users, or iBook users if they ever want to swap batteries. Since only the 15 and 17 inch Powerbooks allow battery swapping currently when in sleep mode, this at least gives Apples entire lineup the possibility of swapping now without losing work.

Desktops might find this handy if attached to a UPS. Enable it, and set the system to go to sleep when the UPS goes to battery power. That way even if the UPS dies, the system will still come right back from where it was.

I think Apple's decision to not seperate this into multiple things like Windows does shows their typical refined though process. Sure, Windows does hibernate. Sure, it does sleep, but you have to pick between them.

testudo
Fresh-Faced Recruit

Joined: Aug 2001

0

11/16, 04:47pm | report spam | close Reply |
Re: why

Here's the WHY: Put your powerbook to sleep. Something jars your battery lose, it goes dead, you forget to put another one back in (orjust don'tdo it quickly enough because your kid fell down the stairs (happened to me). When it's completely out of power, it switches to using the safe mode, and will restore from disk instead of being the equivalent of unpluggin your desktop while on.

Well, here's the problems with your examples. First, if you set it up to safe sleep after a period of time (like you do on windows, so it sleeps for 4 hours, then hibernates), then if the battery pops out in the first four hours, you're still screwed. If you're not 'sleeping' but the computer is on when the battery gets jarred, you lose power and all your work anyway. Of course, I'm basing this on my iBook, which, when won't let you swap a battery asleep or anything like that (maybe powerbooks can handle being asleep for a short time without battery, but doubt it would help if your computer was on and working).

the switching to safe sleep while sleeping only would work if your computer actually can track your battery well. My iBook sucks at this (I need a new battery, though). It goes from 100 to 75% then just goes to sleep without warning.

And it would be nicer if Apple could just enable this for all their computers, esp. if you have a desktop tied to a UPS, be nice not to lose your work if the power went out for more than a couple of seconds while you're off finding candles.

wings_rfs
Fresh-Faced Recruit

Joined: Dec 2002

0

11/16, 05:13pm | report spam | close Reply |
What they probably do...

is save RAM to disk as soon as sleep mode is entered, and NOT after waiting until the battery is critically low. Then if the battery dies abruptly or gets removed the RAM data is ready & waiting on disk.

apple4ever
Fresh-Faced Recruit

Joined: Jan 2001

0

11/16, 07:16pm | report spam | close Reply |
Really cool

This is a really cool feature. Its real useful if your battery is low and the computer goes to sleep, and then the battery runs out even while asleep. Now instead of going through the bootup sequence, it just reloads the state that the Mac was in. I can't be the only one who has a bunch of email messages and web pages and other apps and docs open. Even if its saved, I still have to go back and open everything up and get everything back to how it was. That's a pain. Now I don't have to worry about it.

Oh, and for those who don't understand how it works(hint: read the article) This is the process:

1. Close lid or choose sleep from the menu. 2. The Mac automatically saves the entire contents of RAM to the HD. 3. It goes to sleep now like any other Mac. 4. If the battery power is lost, everything in RAM is lost. 5. When a power source is reconnected, and the Mac is started, it copies the state from the HD back into RAM. 6. The Mac than "wakes up" like any other Mac.

doughboyj
Fresh-Faced Recruit

Joined: Mar 2002

0

11/16, 08:25pm | report spam | close Reply |
works on a Ti

I have a Ti Powerbook (550mhz) not sure when it came out but you can switch the batteries in it during sleep mode, i just swap the batteries immediately during sleep and no problems happen.

resuna
Fresh-Faced Recruit

Joined: Jan 2005

0

01/14, 06:13pm | report spam | close Reply |
Better than Hibernate.

According to apple's page:

"Prior to your system entering sleep, Safe Sleep automatically saves the contents of main memory�such as desktop settings, open applications, and other work in progress�to the hard drive."

What this sounds like is that it's not going from active, to sleeping, to hibernating. Instead it's making a disk snapshot when it sleeps, as a backup, and it only uses it if it fails to wake from sleep.

In many ways this is better than having a separate hibernate state, because even if the battery gets removed while you're in "sleep" mode... even if only seconds after going to sleep with a fully charged battery... it will recover.

It would be nice to have a mechanism to take this snapshot and then completely power off if you're not going to use your laptop for a few days, so that when it comes up again it'll return from Safe Sleep fully charged. I guess you could just sleep it and remove the battery, but that seems a bit of a kludge.

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New "Safe Sleep" mode on Mac laptops

updated 01:45 pm EST, Wed November 16, 2005

PowerBook \'Safe Sleep\'

sounds familiar...

Now instant wake...

Doesn't work on TiBooks

Back in the day...

Pismo had it...

Hmm...

Why to do this...

iBook G4

No reason to hack it in

Multi-stage sleep...

Useful for 12 inch PBs

Re: why

What they probably do...

Really cool

works on a Ti

Better than Hibernate.

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New "Safe Sleep" mode on Mac laptops

updated 01:45 pm EST, Wed November 16, 2005

PowerBook \'Safe Sleep\'

Related Articles

Recent Articles

sounds familiar...

Now instant wake...

Doesn't work on TiBooks

Back in the day...

Pismo had it...

Hmm...

Why to do this...

iBook G4

No reason to hack it in

Multi-stage sleep...

Useful for 12 inch PBs

Re: why

What they probably do...

Really cool

works on a Ti

Better than Hibernate.

Login Here

Register for our weekly email newsletter:

Connect tools:

Subscribe

to our RSS

Follow us

on Twitter

10 Most Read

10 Most Discussed

MacNN Marketplace