I had this discussion recently about the size of MP3 players...
I bought a 4 GB, but my computer displays it as 3.73 GB
3.73 GB * 1024 = 3819.52 MB
3819.52 MB * 1024 = 3911188.48 KB
3911188.48 KB * 1024 = 4005057003.52 B
Now, when I look into my physics book, I see that G stands for 10^9.
So 4005057003,52 = 4 * 10^9 B, which is correct.
It's just a marketing trick to give you the impression you buy more than what you'll get in the end and the worst thing is: it's all correct, so you can't complain
Anyway, TheMusicPirate's case:
4190.5 MB * 1024 = 4291072 KB
4291072 KB * 1024 = 4394057728 B
which equals 4.4 * 10^9 B or 4.4 GB if your vendor applies the same marketing trick.
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