The reason is as madmax stated. Notice that 2048 is 20.48. It all has to do with computer one's and zero's. they could have just as easily used 1024(10.24) or 4096(40.96) but chose 2048 (20.48). As Susan Kitchen says, "It's like wondering why there are 12 inches in a foot...Once you live in the real world it makes sense. Or at least you get used to it." :)