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superjanyesterday at 7:31 PM1 replyview on HN

Well the 1.44 MB, was called that because it was 1440 KB, twice the capacity of the 720k floppy, and 4x the 360k floppy. It made perfect sense to me at that time.


Replies

okanattoday at 1:35 AM

It may "make sense" but that's actually a false equivalence. The raw disk space for a 3.5" high-density floppy disk for IBM PCs is 512 bytes per sector * 18 sectors per track * 80 tracks per side * 2 sides = 1,474,560 bytes. It is 1.47 MB or 1.40 MiB neither of which is 1440 KB or KiB. The 1440 number comes from Microsoft's FAT12 filesystem. That was the space that's left for files outside the allocation table.

Sectors per track or tracks per side is subject to change. Moreover a different filesystem may have non-linear growth of the MFT/superblock that'll have a different overhead.

https://en.wikipedia.org/wiki/List_of_floppy_disk_formats