This article details hibernation support on a PGP Whole Disk Encrypted operating system.
Hibernation is a power option feature of an operating system that can save the state of the system to preserve battery life. This feature is mostly used with laptops that use battery power and can help restore the state of the system, including applications that were being used at the time of hibernation. Hibernation can be configured to occur automatically at specified time period or manually.
PGP Whole Disk Encryption behaves differently with hibernation depending on the operating system being used.
PGP Whole Disk Encryption is fully supported with hibernation in Windows. If a PGP Whole Disk Encrypted Windows system enters hibernation, upon restoring power to the system, the PGP BootGuard will prompt you for your passphrase. After entering your passphrase the disk is decrypted and returns to the previous state.
Mac OS X
PGP Whole Disk Encryption is not supported with hibernation mode in the Mac OS X. In Mac OS X, an image file is created upon hibernation of the system. Once power is restored, the state of the system is restored, including any open programs or other processes that were running. The location of this file is in /var/vm/sleepimage and is the size of RAM memory on the system.
This mode may be referred to as Safe Sleep, Deep Sleep, or Hibernation. This is not the normal Sleep mode in which the power can remain on, but the system is essentially idle. This mode does not keep an image of the processes, but rather the information is stored in the RAM memory.
The Mac OS X operating system does not support foreign file systems for hibernation. Mac OS X Hibernation mode is not supported with "boot != root". This "boot != root" is essentially the system used by Mac to boot a foreign file system. For PGP Whole Disk Encryption to boot a system, a special file system is used which is considered foreign. As PGP Whole Disk Encryption is considered a foreign file system, hibernation mode is not supported by the Mac OS X.
As a safeguard to prevent system issues and data loss, PGP Desktop disables the hibernation mode on Mac OS X. Although Sleep will still work, deep sleep does not build a sleep image.