Posted by: Chris Barylick
Date: Monday, April 6th, 2009, 09:03
Albeit generally reliable, putting your MacBook or MacBook Pro notebook to sleep can be a bit of a gamble. When you open the notebook back up, you want to make sure the computer will wake up again or your day just got that much worse.
Over on the Apple Core, David Morgenstern has offered the following tips in getting his MacBook Pro to wake from sleep under both Mac OS X 10.4 and Mac OS X 10.5.
Per Mac OS X 10.4:
1. Before I put the machine to sleep, I unplug anything connected, such as an Ethernet cable, hard drive or mouse.
2. Next I use the Sleep command under the Apple Menu to put the MacBook to sleep and I wait until the screen actually goes blank before closing the lid. I don’t just close the lid.
3. When I go to wake the MacBook, I open the machine and make sure that I don’t plug anything into the machine before I wake it.
Interestingly enough, Mac OS X’s Energy Saver panel allows for multiple types of sleep (“computer sleep,” which is what we commonly think of as sleep, where the system sleeps; “display sleep,” where the screen goes black; and “hard disk” sleep, where the drive spins down).
The column then mentions that the following types of sleep can be used:
Sleep, where the Mac saves the state in RAM, which means it can go to sleep and wake up quickly, but could bring trouble if the battery runs down or is removed.
Hibernate, where the state is written to the hard disk (the safest for your data), but takes the longest time to be put to sleep and to wake up.
Combination Sleep and Hibernate, which Apple calls Safe Sleep. It may take the longest time to sleep but it also can wake quickly. And if your MacBook supports it, you can swap in a fresh battery.
For users looking to specify the sleep type used, software developer Patrick Stein’s SmartSleep lets you choose between the modes.
For users experiencing problems getting their MacBook notebook to sleep, Apple’s “Why Your Mac Might Not Sleep or Stay in Sleep Mode” Knowledge Base article offers the following tips:
There are reasons why you may want your Mac to stay awake even though you are not using the keyboard or mouse, such as when you are:
Watching a DVD movie
Listening to your iTunes music library
Running an automated backup
Away from your computer while downloading large files
The article also mentions that using Bluetooth devices can disrupt a MacBook’s sleep function:
You can allow Bluetooth devices to wake a sleeping computer by enabling “Allow Bluetooth devices to wake this computer” in Bluetooth preferences. A bluetooth device paired correctly should not typically prevent a computer from sleeping. However, some Bluetooth mice can interfere with sleep.
Finally, applications themselves can affect sleep:
If an application uses a custom font to display text but the font resource is marked purgeable, then at some point the memory manager will purge the font from memory. When the application tries to draw text using that font again, it will be loaded from the hard drive, resetting the sleep timer.
Applications can be designed to keep the system awake and prevent idle sleep indefinitely. In developer lingo, an application may explicitly prevent system sleep by calling IORegisterForSystemPower(), and calling IOCancelPowerChange() when it receives a power management kIOMessageCanSystemSleep notification.