Filesystem should always be created on a block device.
Filesystem is created using ‘mkfs’ command. mkfs –t fstype
Specific filesystem utilities may be called directly as mkfs.ext2, mkfs.ext3, mkfs.msdos
Example:-
Creating file system on a floppy diskette
# mkfs –t msdos /dev/fd0
Creating file system on a hard disk partition
# mkfs.ext3 /dev/hda1