The article links to this wikipedia entry on one of the pages: http://en.wikipedia.org/wiki/KiB

Basically, the SI units kilo-, mega-, giga- all refer to powers of 1000. The word "gigabyte" suggests that it's composed of 1000 megabytes. But that's not how storage works, because storage is ACTUALLY based on powers of 1024. A gigabyte is ACTUALLY 1024 megabytes.

I wanted to be very clear about how much data the drive can write.

8 bits = 1 byte
1024 bytes = 1 kibibyte (1KiB)
1024 kibibytes = 1 mibibyte (1MiB)
1024 mibibytes = 1 gibibyte (1GiB)

This discrepancy is why a "250GB" hard drive (Which you would think is 250,000 megabytes) is actually 244,000 mibibytes, because the computer judges values in powers of 1024. So 250,000/1024 = 244,000.

It's confusing and stupid.