How to differ ZCLV/PCAV from CLV/CAV?


I know how to differ CLV from CAV: different rotation control value, WRC in write descriptors. But I do not know how to differ ZCLV from CLV and pCAV from CAV ? What cdb should I use ?




I wonder how to change the speeds for ZCLV, CAV and pCLV. For example, for some zone, ZCLV support the speed to be 5540 and the previous zone speed is 2770. I think when it read or write to the current zone, the speed will be reset by itself. Is that correct ? And after that, can we keep the speed of 2770 by setting the speed to be 2770 ?




Set the Get Performance CDB[10] to the Write Speed
(Type field = 03h) format. Byte zero/bits 3 & 4 of the Write Speed Descriptor contains the default rotation control value for the disc in the drive i.e . CAV, CLV or ZCLV. You need to interpret the return based on disc type and max speed capability.

For CAV and PCAV (Partial Constant Angular Velocity) for CD-R/RWs, it may be safe to assume that CD-R/Ws with write speeds faster than 8x would be PCAV and use CAV up to 8x and CLV from that point up to their max speed whatever that may be
i.e. 12x,16x, 24x, etc.

MMC/MtFuji says the default rotation control for DVD plus & minus is CLV and ZCLV for DVD-RAM. So if you ID the disc with
Get Config/Profile you can tell if the return refers to ZCLV or CLV. This does not mean the default rotation control will be used for a write operation. DVD plus & minus can use ZCLV & PCAV as well. So I wouldn’t recommend automatically setting DVD+/- to CLV with
Set Streaming.

Often it’s best to let the drive determine the best rotation control for the disc.


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