640kb more like! Don’t get me started on upper and lower ram DOS nonsense…

Back in the days of DOS/MS-DOS, all filenames were in uppercase and restricted to 8 letter filename and 3 letter extension.

Because Windows was always just built on top of DOS and the FAT filesystem, until NT/Win2000, the actual file naming convention renamed the same.

Windows just held extra metadata to pretend it could have longer filenames.