IBM THINKPAD S05L-1270-01 - Manual (Page 149)

Hibernation Mode: In hibernation mode, the
following occurs:
The system status, RAM, VRAM, and setup data are
stored on the hard disk.
The system is powered off.
Note
The computer cannot enter hibernation mode when
the computer is powered with ac power and a
communication PC Card is used.
Events that initiate hibernation mode:
Hibernation mode is requested by the Fn key
(Fn
+ F12).
Timer conditions are satisfied in suspend mode.
A critically low battery condition occurs.
The PS2 HIBernation command is set in the
ThinkPad Features program.
The computer exits hibernation mode and resume
operation when the power-on switch is operated. When
power is turned on, the hibernation history in the boot
record on the hard disk is recognized and system status is
restored from the hard disk to resume operation.
ThinkPad 560, 560E (2640) 137