Replacing The Battery; Saving To Disk - Texas Instruments Extensa 660 Series Maintenance Manual

3.7.4 Replacing the battery

If you have a spare, charged battery, you can do one of the following.
Insert a secondary battery into the modular bay.
If you already have a battery in the modular bay, you can replace the primary
battery without turning off the computer.
If you cannot insert the spare battery into the modular bay, suspend operations
to disk by pressing Fn+F2 and replace the battery. When you turn on the
computer, the computer returns to the saved state.

3.7.5 Saving to Disk

When the battery power becomes critically low (less than 5% charge remaining), the
computer saves the current state of the computer to disk and turns off. When you turn
the computer on again, the computer restores the state that was saved to disk.
3-10 Operating Instructions