For laptop users, the ability to hibernate a Windows session can be a pretty useful tool. In a nutshell, hibernation allows Vista to copy the contents of your computer's memory to hard disk and then power down without completely turning itself off, thus saving precious battery resources and allowing you to pick up where you left off at some other time (like after you get off a plane). Pretty cool, but it comes at a cost.
If hibernation is enabled on a PC, Windows will create and reserve a file called hiberfil.sys approximately equal in size to the amount of RAM you have on your system, even if you never intend to use hibernation. If you have a PC with 4 gigs of memory, then this feature might be silently laying claim to a pretty substantial piece of your disk real estate. In "always-on" scenarios, where you are running a Windows machine that you never intend to hibernate, you'd probably think it would be nice to just turn this feature off and reclaim that huge chunk of wasted disk space that you'd previously been freely donating to the OS.
In XP this was an easy thing to do, just open the Power Options in the control panel and uncheck the box to allow hibernation. In Vista this is not the case, there are no Power Options settings that will let you directly control whether hibernation is enabled or not. All is not lost however, but you do have to get up close and personal with your administrative command prompt in order to enable/disable this feature.
To disable hibernation in Vista you need to take the following steps:
- Click the Windows button and type cmd in the Start Search box.
- In the search results list, right-click Command Prompt and click Run as Administrator.
- If you have UAC turned on, you will need to give it permission to Continue.
- At the command prompt, type powercfg.exe -h off, then press ENTER.
- Close the command window.
To re-enable hibernation simply repeat the same steps and use the substitute comand powercfg.exe -h on for step 4.
Or if you are really a Vista shortcut geek, you can simply type the appropriate powercfg.exe command in the Start Search box and hit Ctrl+Shift+Enter to execute it (Ctrl+Shift+Enter is a keyboard shortcut to run a command with admin privileges). A command prompt will flash and disappear, but since the powercfg app doesn't give you any feedback when you run it anyway, you won't really be missing anything.
So go grab yourself that extra disk capacity, it could come in mighty handy on machines that might be starving for some available disk space.