RehabMan
Moderator
- Joined
- May 2, 2012
- Messages
- 181,058
- Motherboard
- Intel DH67BL
- CPU
- i7-2600K
- Graphics
- HD 3000
- Mac
- Mobile Phone
Thanks RehabMan for your support, what i have is a hybrid HDD from Seagate with 8GB SSD don't know if will be ok to delete the sleep image on this hdd.
Thanks
It does not depend on HDD type/hardware. sleepimage and hibernate style sleep is not a requirement. The only use is to safely bring the computer back from sleep in the case of total power loss.
scenario 1 (power loss):
1. laptop goes to sleep on battery power (or power is lost eventually at AC circuit), because of sleepimage availability/setting, OS X saves the contents of RAM/state to HDD as a sort of 'plan B' for wake
2. laptop is sleeping long enough to eventually lose all power, thus the contents of RAM are lost
3. when laptop is turned back on RAM/state is restored from the image on the HDD
scenario 2 (no power loss):
1. laptop goes to sleep on battery power (or power is lost eventually at AC curcuit), because of sleepimage availability/setting, OS X saves the contents of RAM/state to HDD as a sort of 'plan B' for wake
2. laptop wakes before losing power, so it instantly wakes up with the contents of RAM intact
scenario 3 (power loss, no sleepimage/non hybrid sleep):
1. laptop goes to sleep on battery power (or power is lost eventually at AC curcuit), because of sleepimage availability/setting, OS X does not save RAM anywhere
2. laptop is sleeping long enough to eventually lose all power, thus the contents of RAM are lost
3. when laptop wakes, it is a cold boot. OS sees last session it as a (somewhat) hard/unexpected shutdown
Windows calls this hybrid sleep (a rare case where Windows has a better name for something). Basically, the OS prepares for hibernation even in the case of standby sleep.
This does cause a lot of writes (up to the amount of RAM in the machine) on each sleep cycle, so that's why it is not great for SSD as it reduces the lifetime of the SSD. But as you can see it is really a failsafe mechanism to account for total power loss, which if you keep your laptop plugged in during sleep (eg. overnight), then it is rarely an issue.
Plus my idea was to turn it off, then turn it back on, which will re-create the sleepimage. As a test anyway. Certain machines (OS X hacks) have problem resuming from sleep image for some reason. I don't use it (all SSD), so I haven't looked into it.