Modern computing devices employ power-saving modes when not in use. Hibernation is a mode in which an operating system (OS) saves memory data from volatile system-memory to an OS boot partition of a hard drive in the form of a hibernation file, after which the computing device is shut down. When turned back on, the basic input output system (BIOS) of the computing device posts and then loads an OS boot loader. The OS boot loader copies the memory data within the hibernation file back into the volatile system-memory. The OS boot loader then resumes operation of the operating system where the operating system was paused instead of booting the operating system as normal. This allows for currently running applications to retain their data even if the data was not saved before hibernation.
Suspend is a mode in which the operating system shuts down power to most of the devices within the computing device but not to the volatile system-memory such that the memory data is preserved. To resume full use, the operating system powers on the devices and resumes operation using the memory data that was preserved. Suspend uses significantly more power than hibernation but is much faster.
While these modes serve their respective purposes they have undesired limitations. Hibernation mode can be slow to begin and can lose data. Hibernation mode can be slow to begin because it is limited by the speed at which the hard drive can save the memory data to the hibernation file. A computer's data is often stored on a spinning-media hard-disk drive, which is spinning while the hibernation mode is beginning; this presents a data-safety issue. Any substantial movement of the computing device is potentially hazardous while the drive is still spinning. A user who selects to hibernate his laptop, closes the lid, and goes on his way may damage the hard drive and the data it contains. Furthermore, during the time that the hard drive is spinning, both it and the computing device are using power. This is undesirable if the hibernation occurred due to a critical battery alarm because the computing device may run out of power before the hibernation is complete. Even if the device's battery does not fail, using additional power contradicts the point of a power-saving mode.
Suspend mode also has undesired limitations. While significantly faster than hibernation, it uses more power because the volatile system-memory remains powered. Furthermore, if the computing device's power source is lost while suspended, the memory data may not be recovered and any information not saved to the hard disk will likely be lost. This can easily occur, such as when the user unplugs the computing device or when a power source fails.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.