I could swear this was the cluster size for FAT32 on a 2G drive, but apparently not[1], this is the cluster size for FAT16 on 2G. FAT is just utterly dumb in ho

I could swear this was the cluster size for FAT32 on a 2G drive, but apparently not[1], this is the cluster size for FAT16 on 2G. FAT is just utterly dumb in how it does space allocation: it doesn’t even have a bitmap, it’s just a gigantic dense array of linked list nodes (the eponymous file allocation table). Perfectly fine for a 360K floppy on a 32K machine, predictably painful for a 2G hard drive on a 32M machine. Add in narrow allocation unit (“cluster”) numbers, and you end up with huge allocation units. As far as I can see, ext2/3 instead use a free bitmap and a tree-style “indirect block” setup that is recognizably similar to (though greatly extended from) V1 UNIX (1971) [2], predating even the original FAT8 (1977). Ext4 can do extent [that is, (start, end) pair] allocation instead, and XFS, ZFS, Btrfs, etc. are built around it. Thus they can and actually do manage disk space in smaller bits. [1] https://support.microsoft.com/topic/default-cluster-size-for-ntfs-fat-and-exfat-9772e6f1-e31a-00d7-e18f-73169155af95 https://support.microsoft.com/topic/default-cluster-size-for... [2] http://squoze.net/UNIX/v1man/man5/fs http://squoze.net/UNIX/v1man/man5/fs or https://www.bell-labs.com/usr/dmr/www/pdfs/man51.pdf https://www.bell-labs.com/usr/dmr/www/pdfs/man51.pdf