writing outer tracks, thus approximating the performance of constant linear velocity drives. Products that use ZBR Commodore 1541 floppy disk (combined ZBR, ZCAV and GCR for 17–21 sectors á 256 bytes in 4 writing speed zones) Sirius 1/Victor 9000 floppy disk (combined ZBR, ZCLV and GCR for 11–19 sectors á 512 bytes in 9 rotation speed zones) Apple Macintosh 400K/800K floppy disk (combined ZBR, ZCAV and GCR) DVD-RAM Most hard drives since the 1990s See also Zoned constant linear velocity (ZCLV) Constant linear velocity (CLV) References Rotating disc computer storage media