What is the Windows hibernation file used for?

• A. memory.dmp
• B. hiberfil.sys
• C. swapfile
• D. pagefile.sys

Answer: (B)

The concept being tested is how Windows preserves a full system state when you power off by using a dedicated on-disk image of RAM. The file used for this is hiberfil.sys. When you put your computer into hibernation, Windows saves the entire contents of memory to this file so the exact state of all running programs and open documents can be restored when you resume. This allows a complete power-off without losing work, unlike sleep which keeps RAM active in a low-power state.

This is different from a crash-dump file like memory.dmp, which is created to analyze a system crash after it occurs. It’s also distinct from a swap or page file (swapfile or pagefile.sys), which are used for virtual memory paging to disk during normal operation, not to store a full RAM image for hibernation. hiberfil.sys is the specific file Windows uses for hibernation, typically on the system drive, and its size is tied to the amount of RAM.