ZCAV
Zoned constant angular velocity — spin the disc at a fixed rate but pack more sectors into the roomier outer zones.
Pure CAV holds the spin constant (simple, but it wastes the outer tracks' space); CLV varies the spin for a constant data rate (audio CDs, but slow to reseek). ZCAV splits the disc into concentric zones, keeping the spin fixed within a zone but adding sectors per track further out — the optical cousin of hard-disk zone bit recording. Fast CD and DVD drives used ZCAV or partial CAV (P-CAV) to raise average throughput.