Number::Compare compiles a simple comparison to an anonymous subroutine,
which you can call with a value to be tested again.

Now this would be very pointless, if Number::Compare didn't understand
magnitudes.

The target value may use magnitudes of kilobytes ('k', 'ki'), megabytes
('m', 'mi'), or gigabytes ('g', 'gi'). Those suffixed with an 'i' use the
appropriate 2**n version in accordance with the IEC standard:
http://physics.nist.gov/cuu/Units/binary.html