How to open C drive when Windows is hibernated?

Windows saves the information needed to wake up from hibernation usually in the "C" drive, in a file named hiberfil.sys. Its size is approximately the size of your RAM and is stored on the hard disk when the computer is asked to hibernate.

Because the system is hibernated and needs to be in the same state when revived, the partition is made read-only and should not be changed from another operating system, if it is a multi-boot system. So, when you open your Windows drive from a Linux-based operating system, such as Ubuntu, you may get an error message such as this:

The error message obtained when the hibernated Windows partition is asked to mount.

You can retrieve your data from this drive, without having to open Windows in steps:
1) Open a command-prompt, such as your gnome-terminal.
2) Type

sudo mount -r /dev/sda2 /media/your_username

In place of sda2, type the name of the device where your Windows is installed, like sda1 or sdb1 or something like that. To see which device on your Windows is installed on, type

sudo fdisk -l

and try to recognise the Windows partition by looking at the "blocks" column which shows the size of the Windows partition. And in place of your_username, type your user-name or type /media/ and press tab to see a list of options or the correct option itself! The "C drive" is now mounted and you can see your data!

Caution: Do not try to modify any thing in the Windows drive, even if it may seem to be abnormal as this may cause your data to be lost which may not have been saved while hibernating.

Difference between Shut down, Hibernate and Suspend options

The “Hibernate” option is a tool capable of saving our current session and then powering down, unlike the “Shut down” option, which closes all open applications and then powers the system off. Here, we compare the Shut down, Hibernate and Suspend options and then try to figure out which one to use for a particular session. 

Parameter	Shut down	Hibernate	Suspend
Powers down the system	Yes	Yes	No
Closes all open applications	Yes	No	No
Consumes power	No	No	Yes
Relative time to power down*	Highest	Moderate	Least
Time to wake up*	Highest	Moderate	Least
Thus, particularly useful when	Hardware is to repaired or replaced	The system is not in use for a long period of time, say, more than 2 hours	The system is not in use for a short period of time, say, upto 2 hours and the system has enough battery power to stay alive

*Actual time depends on the environment like the processor, RAM, Operating System under consideration, viruses, etc.

It should be that, the “Hibernate” option saves the current session to Hard disk, on one of the partitions on which the Operating System(Microsoft Windows or Canonical Ubuntu, etc) resides. So, when you hibernate, the Operating System locks the partition and makes is unopenable from the other operating systems, in a multi-boot computer, until the partition is either mounted as a read-only partition, or the OS that hibernated is resumed and shut down.

For example, if you have a computer that has Microsoft Windows 7 and Ubuntu 12.10 dual booted and you hibernate from Windows, you may not be able to open the “C” drive until you open Windows and use “Shut down”. This means if your Windows accidentally crashes, recovering data from the “C” drive would become a bit complicated, unless you apply some kind of work around like copying files after mounting the partition as read-only.

3 Power tips when using laptop and related portable devices

Laptops and other portable devices are meant to be used for convenience and portability. However, there are many times when we have a choice and have no idea about the advantage of one over the other and just use the one we have been using over the years. Here are some suggestions that can help your choice for the better:

1) Keep your laptop always, or whenever possible, plugged into AC power: Most modern day batteries are Lithium ion batteries, compared to Nickel Cadmium batteries of olden days. These are a bit costlier but last longer and do not develop the "Memory Effect" that the olden batteries suffered from. So, instead of charging and discharging always and consuming the chemicals that compose the battery, it is better to let the laptop be plugged in to the main supply whenever possible and save the battery a few more months or may be even years.

2) Hibernate, instead of shut down: The "Hibernate" option saves your current session to hard disk, meaning all open files and applications, and then powers down the laptop, thus, not only saving power but also booting up much more faster than the usual boot up if you had shut it down.

However, do this with caution especially if you have a dual boot system, because if you hibernate, you won't be able to open the partition which houses the operating system you have put to hibernate and it returns an error, saying you need to shut down the other operating system and then try to open this partition. Other than this, you need to shut down only when you need to work with the hardware of your system like changing your RAM or replacing your hard disk.

3) Never move your laptop when powered on: Moving your laptop when it is powered on may lead to physical damage of some critical components of the hard disk which has many moving parts like the platter and the actuator arm. The head of the disk arm is very close to the platter which rotates at a very high speed(of the order of 5400 to 7200 rotations per minute). If the arm accidently touches the surface of the platter at this speed, it may lead to loss of data or even losing the entire hard disk to permanent physical damage.