CLV, CAV, Z-CLV, best for most reliable burn?

vbimport

#1

CD recording was based solely on CLV technology until 16x recording speed, at which speed the rotational speed at the inner track reaches 8,640RPM.

Laser and the chemical dye was capable of accepting higher linear velocity, but increasing the spindle speed much above ~9,000 RPM would make vibration management and tracking difficult. The next generation was based on Z-CLV technology which starts at 16x recording speed and increase speed in steps. In each step, recording speed is kept constant and a graph of the recording speed would look like a stairway. This seems to be the most common recording stragegy in modern recorders.

There are some recorders using CAV (constant angular velocity) writing method which is based on constant spindle speed and varying writing speed as the laser moves across the radius.

Which writing method produces the highest quality burns if any consistent difference between the methods?

I can name pros and cons for each method, but I do not know how they actually interect with writing quality.

Pros:
CLV: The laser sees the disc moving at the same linear speed (m/s) throughout the whole recording session therefore the interection between the dye and the laser is consistent.

Z-CLV: Permits higher speed than 16x

CAV: Spindle speed is kept constant while the write speed constantly changes. Constant spindle speed can keep the vibration amplitude and frequency constant.

Cons:
CLV: varying RPM will cause the disc to vibrate at different amplitude and frequency as RPM approaches and drifts away from the natural resonance of the disc which could theoretically effect write quality

Z-CLV: Because the laser must change power each time the write speed is in changed and the data flow stopped while the speed is being changed, consistent burn may not be guanrateed and there maybe a seem at transition process which may become an issue when you burn a pre-master disc.

CAV: The interection between organic dye and laser can’t be predicted exactly as the linear velocity and laser power must be changed continuously.

So as you can see, each have good and bad with the Z-CLV being the worst of all. I’m not sure what method produces the best burn, but I always record anything important at 12x or 16x.

Any input?


#2

The two Z-CLV 16x recorders are Pioneer DVR-A08 and Hitachi-LG GSA-4160B. Hitachi-LG’s GSA-4163B uses P-CAV 16x which starts at 7.3x and reaches 16x at about 3.5GB point (out of total 4.3GB disk area.) GSA-4163B 16x P-CAV write quality seems to be much better than GSA-4160B 16x Z-CLV. They are all relatively good at 16x writing. Hm… but you were talking about CD, not DVD. :slight_smile:


#3

I think you should be more worried about the quality of the media and how well the drive likes it as opposed to the benefits of (Z-)CLV or (P-)CAV.

Also if you are terribly worried about losing your data due to not-so-good burns, then you should be burning multiple copies on different media types. Even if you have the best media, burner and write strategy, this does not excuse you from using proper backup procedures.


#4

It’s also a good idea to store the same data on a remote server in case of physcal disaster like fire and drought. Very unlikely, but that’s the sole reason for backups after all. I once experienced drought, serious enough to make most of my personal backups less than failed CD-R disks.