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mount -o loop ./tinycore /mnt/datamount: you must specify the filesystem type
tc@box:/mnt/hda3/1/TinyCore$ sudo mount -o loop ./tinycore /mnt/datamount: mounting /dev/loop21 on /mnt/data failed: Invalid argument
tc@box:/mnt/hda3/1/TinyCore$ sudo mount ./tinycore /mnt/datamount: mounting /dev/loop21 on /mnt/data failed: Invalid argument