> Don't hard drives use MB (to inflated advertised capacity? You decide) as standard. They do, but that's not what diskettes did. Hard drives use KB = 1000 B,

> Don't hard drives use MB (to inflated advertised capacity? You decide) as standard. They do, but that's not what diskettes did. Hard drives use KB = 1000 B, MB = 1000 KB, etc. as units. This makes the number on the side of the packaging larger, so it's good for marketing. They used to use 512 B sectors internally. (Today, HDDs have moved to 4 * 1024 B sectors, or 4 KiB, I believe.[4]) ([1]) 3½" diskettes were 1474560 B (1440 KiB). If we use the programmer's "KiB", where 1 KiB = 1024 B, 1 MiB = 1024 KiB, we get 1.40 MiB. If we use the marketer's 1 KB = 1000 B, 1 MB = 1000 KB, we get 1.47 MB. The only way to get that 1.44 number is to mix the two: 1474560 B / (1024 B / KiB) / (1000 KB / MB). This is of course utter nonsense. But I guess it got to a point where it would be weird, I guess, to not label your packaging as "1.44 MB", and so it was, until the USB drive killed diskettes[2]. (This mix happened because the size was "1440 KB", and from there, someone moved a decimal point without understanding why that didn't make sense.) [1]: I'm going to use the binary SI unit prefixes (https://en.wikipedia.org/wiki/Binary_prefix https://en.wikipedia.org/wiki/Binary_prefix) for clarity, but back when diskettes where popular, 1024 B was notated as 1 "KB", and it was up to context to determine if the author meant 1024 B or 1000 B. The binary prefixes didn't exist until '98, let alone were they adopted, and diskettes would die a quick death soon after that. [2]: Or CDs, if you had a burner. Or Zip drivers or Jazz drives if you did that. [3]: The "1.44 MB" storage device was rigid. It wasn't floppy in the least. It was a diskette. The 5¼", that was floppy. [4]: https://en.wikipedia.org/wiki/Advanced_Format https://en.wikipedia.org/wiki/Advanced_Format