If the system was improperly halted, you may see the message:
There may be a system dump memory image in the swap device. Do you want to save it? (y/n)This memory image contains technical data about the state of the system when operation was interrupted. Information about preserving and analyzing this data is discussed in ``Recovering from a system panic''. If you respond n, you are then asked if you want to delete the image; enter y to save the image and continue.