DCCs are similar to compact cassettes, except that there are no "bulges" where the tape-access holes are located. DCC cassettes are flat and there are no access holes for the hubs on the top side (they are not required because auto-reverse is a standard feature on all DCC decks), so this side can be used for a larger label than can be used on an analog compact cassette. A spring-loaded metal shutter similar to the shutters on 3.5 inch floppy disks and MiniDiscs covers the tape access holes and locks the hubs while the cassette is not in use. Cassettes provide several extra holes and indentations so that DCC recorders can tell a DCC apart from an analog compact cassette, and so they can tell what the length of a DCC tape is. Also, there is a sliding write-protect tab on the DCC to enable and disable recording. Unlike the break-away notches on analog compact cassettes and VHS tapes, this tab makes it easier to make a tape recordable again, and unlike on analog compact cassettes, the marker protects the entire tape rather than just one side.