Formatting

   Preparing a storage medium (usually magnetic media such as a
disk or tape) for storing data.  Low-level or physical formatting
writes all necessary housekeeping data to enable the storage device
to read the media and may also initialize the storage units on the
media to a known state.  High-level or logical formatting writes data
used by the operating system, such as allocation information and
directories onto media which has already been physically formatted.
Formatting programs often perform both a low-level and a high-level
format.