Eighty gigabytes

A few days ago, I bought an 80GB hard disk in a USB enclosure. When I plugged it in, I found it was preformatted to two 30GB partitions.

Hmmm. 30+30... carry the two... minus the number you first thought of... you do the maths.

Hard disk manufacturers are notorious for inflating the size of their disks (e.g. an 80GB disk using 1GB = 10⁹ bytes is "really" only 74GB using the traditional 1GB = 2³⁰ bytes) but a discrepancy of 25% is ridiculous.