FFS (Fast File System) or FFS2 (Enhanced Fast File System) https://man.openbsd.org/newfs.8#O https://man.openbsd.org/newfs.8#O https://en.wikipedia.org/wiki/U

FFS (Fast File System) or FFS2 (Enhanced Fast File System) https://man.openbsd.org/newfs.8#O https://man.openbsd.org/newfs.8#O https://en.wikipedia.org/wiki/Unix_File_System https://en.wikipedia.org/wiki/Unix_File_System