Have you ever noticed that maybe you bought a computer that advertised that it said “250 gigabytes” of storage and when you got home and booted it up for the first time to find out that windows is reporting it less than that? No, you have not been ripped off. The idea happened some year in the distant past when the idea of kilobyte arrived. Kilo in the metric system means 1,000. Unfortunately, in the computer world kilobyte means 1,024. First lets get comfortable with understanding the system. Below is a chart to review for the moment.

As you can see above there is a difference between the decimal binary value and the decimal only equivalent.  Hard drive manufacturers use decimal only.  They believe in the true metric system.  Meanwhile there is a confusion between computer lingo and the real thing.  Let me show you an example of what I mean.  Below is a graphic out of windows xp pro.  (This is found by going to your my computer, and right clicking on the local disk drive icon, go to properties.)