Which floppy disk?<p>My Apple II floppy drives had 256 byte sectors, groups of which were called a kilobyte.<p>Wikipedia quote: <i>An MFM-based, &quot;high-density&quot; format, displayed as &quot;HD&quot; on the disks themselves and typically advertised as &quot;1.44 MB&quot; was introduced in 1987; the most common formatted capacity was 1,474,560 bytes.</i><p>(Why is it 1.44 MB? That&#x27;s a bit of silliness: it&#x27;s the result of dividing 1,474,560 by 1024, and then just moving the decimal point by three places instead of dividing by 1024 once again. The beginning of idiocy.)<p>All the storage examples you&#x27;re giving are due to dishonest mass storage manufacturers who confused things sometime in the 1990&#x27;s simply by lying.<p>All other storage uses 1024. A gigabyte of RAM is 512 megabytes times two.<p>RAM is not the &quot;exception&quot;; RAM is fundamental. A computer can operate without mass storage, but not without some RAM.<p>A good reason to use powers of two sizes whenever bytes are involved is that <i>the byte itself is a power of two unit already</i>: it has historically settled on 8 bits.<p>A kilobit of data already does not correspond to a power of ten byte value.<p>If you want metric byte storage sizes, then first redefine a byte as 10 bits.  Then a bit can be a centibyte, a byte can be a decabyte. Ten megabits will be exactly a megabyte, and so forth.