standard cassettes), 180 versus 60 for longer-running modes. JVC did market 45-minute and 60-minute SP Mode tapes with the Extra High Grade formulation (135 minutes and 180 minutes in EP/SLP Mode) for a time. Similarly, Video8 spawned a 120-minute version of the cassette (240 minutes in long play). The later Hi8 and S-VHS-C systems both have a quality similar to the LaserDisc system. Although Video8 acquired a digital variant in 1999, Digital8, D-VHS was never adapted to a compact format, as the consumer camcorder industry moved on to small-format MiniDV tapes, then hard-drive- and DVD-based machines, and then solid-state storage. Slackening Problem Early VHS-C cassettes did not have a mechanism to ratchet or lock the supply reel when not in use, making them susceptible to spilling tape inside the shell. Consequently, manufacturers placed a label on their camcorders and adapters to warn the user to check that the tape is not slackened before inserting a cassette. The user could dissipate the slack by manually turning the take-up gear. Later cassettes corrected this problem by adding teeth to the supply reel to lock it in place when no upward pressure is applied. The spindle of the camcorder or VCR supplies pressure to float the reel's turntable and teeth above the shell, allowing it to rotate freely when in use. If a tape with slack was loaded into a VHS-C adapter, the tape could sit on the wrong side of a tape guide when the adapter loaded. The result would be a tape and cassette combination that would not play in a video deck, and would damage the tape to some extent when being unloaded. Write Protect Imperfection VHS-C cassettes have a switch to inhibit recording of a cassette. Not all adapters propagate the state of this switch to the VCR itself, so accidental erasure of a write-protected cassette is possible if the adapter's write protect lug or switch allows it. VHS-C head drum To reduce the size of cameras, the VHS-C mechanism uses a two-thirds size head drum (41.3 mm diameter instead of the original VHS drum size of 62 mm). The wrap angle is 270 degrees instead of VHS's 180 degrees. The drum rotates at a proportionately higher speed, and four rotary video heads are used to trace out exactly the same helical recording path as a standard sized VHS drum. By adding more heads, the same small VHS-C drum