In Windows operating system environment such as Windows XP and Windows Vista system, there is always a file named hiberfil.sys created and existed in the system root drive on boot disk. The hiberfil.sys is large and big in size, always as big as your system physical memory (RAM) size. For example, if the computer have 2 GB of DRAM memory, the hiberfil.sys file size will also be around 1.99 GB in size, taking up precious hard disk space, and in worse case increase fragmentation on the drive.
hiberfil.sys is a file that Windows system creates whenever the computer goes into hibernation mode. When system hibernates, the system state of the computer is preserved by storing a copy of all data in the memory in hiberfil.sys file located on your local disk, so that when the computer restarts, the information can be read into memory to restore the state as of exact state when computer starts to hibernate. That also explains why the size of hiberfil.sys file is always same size with computer's memory size.
(more…)