troubleshooting/tutorials/security

11/16/2005, 1:45pm, EST

Wednesday, November 16th

New "Safe Sleep" mode on Mac laptops

Apple's latest PowerBooks added a new feature called "Safe Sleep"--similar to the "hibernate" feature on Windows laptops--that enables users to return to the system's previous state, even if the battery runs out or is removed. An online guide explains how to implement software feature 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.


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sounds familiar...
0
11/16, 2:14pm, EST
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.
Mac Elite
Joined Nov 2005
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Now instant wake...
0
11/16, 2:17pm, EST
Apparently, it takes about 40 seconds to wake up from safe-sleep as opposed to the nearly instant wake from regular sleep.
Professional Poster
Joined Jun 1999
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Doesn't work on TiBooks
0
11/16, 2:19pm, EST
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).
Fresh-Faced Recruit
Joined Nov 2005
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Back in the day...
0
11/16, 2:21pm, EST
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
Fresh-Faced Recruit
Joined Apr 2003
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Pismo had it...
0
11/16, 2:31pm, EST
at least in OS 9.x So it seems like they brought it back.
Fresh-Faced Recruit
Joined Oct 2004
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Hmm...
0
11/16, 2:53pm, EST
Not really sure why I would want to hack my system to make it do this...
Mac Elite
Joined Jun 2004
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Why to do this...
0
11/16, 3:07pm, EST
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.
Fresh-Faced Recruit
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iBook G4
0
11/16, 4:05pm, EST
Works well on an early 2004 ibook.
Fresh-Faced Recruit
Joined Jun 2004
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No reason to hack it in
0
11/16, 4:17pm, EST
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.
Fresh-Faced Recruit
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Multi-stage sleep...
0
11/16, 4:43pm, EST
... 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?
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Joined Feb 2005
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