Why Z-CLV instead of CAV

I wonder why 8x DVD Writers are firmware programmed to write with Z-CLV instead of CAV or even a straight burn at 8X?

A lot of media has the highest error rates at the lower burn speeds and gets better as the speed increases.

Looking at this kprobe scan, if it burnt at 8x all the way through it would be far better looking than it is.

Comments?

Originally posted by pchilson
[B]I wonder why 8x DVD Writers are firmware programmed to write with Z-CLV instead of CAV or even a straight burn at 8X?

A lot of media has the highest error rates at the lower burn speeds and gets better as the speed increases.

Looking at this kprobe scan, if it burnt at 8x all the way through it would be far better looking than it is.

Comments? [/B]

CAV is a lot harder to do and requires some pretty smart software. That’s why CD writers were Z-CLV to start with. At the moment manufactures can sell more drives by boasting faster speeds then they can from better writes and CAV.

It will happen eventually, but not in the near future.

i agree i loath zclv i wonder if the drives that seem to have the better writing (pioneer, nec) write cav or clv?

Originally posted by cnlson
i agree i loath zclv i wonder if the drives that seem to have the better writing (pioneer, nec) write cav or clv?

Both are Z-CLV. To my knowledge no DVD writer, even Plextor, uses CAV for writing.

When Memorex brought out the true 8x, I thought great a true CAV drive but alas it wasn’t. It just meant +R and -R were both 8x write using Z-CLV… :sad:

i think i read somewhere that a drive manufacturer released a firmware update that would write at 8x cav. just couldn’t remember who.

Originally posted by C0deKing

To my knowledge no DVD writer, even Plextor, uses CAV for writing.
Plextor uses PCAV.

the new toshiba and the sony530 with the newest firm writes in cav mode.

Sony DRU-530A with 2.0a firmware burns 8x DVD+R as P-CAV and Toshiba SD-R5272 burns 8x DVD±R as P-CAV. I think most coming >=12x drives will use P-CAV or CAV (for 16x).

Edit: Too slow :o

at the same time the completely same mind!

Originally posted by konsolen

at the same time the completely same mind!
Great minds think alike. :wink:

So what is stopping them from implementing CLV at 8x for the entire burn?
As you can see in the scan over 50% of the burn is at 8x CLV.
Unless there is a technical reason to do the “steps” I see it as a bad idea.
I have noticed in the latest firmware versions for the 851 the time spent at 4x has increased, which not only increases the burn time but also the higher error generating time.
Surely, Liteon engineeers can see the same things we can…can’t they?
I don’t get it…

But whats better?

CLV vs CAV?
&

P-CAV vs CAV?

I’m not really asking about what’s better from a CAV – P-CAV – Z-CLV point of view.
I am simply stating that the write qualiy increases as the burn speed increases.
So the way I see it, the sooner the drive gets to 8x the better the burn quality overall will be.
The frosting is that the burn time will be decreased.

Again, if it’s due to technical reasons then I can understand it.
But, if it’s by choice then I can’t.

Well, I am asking.

Originally posted by pchilson
So what is stopping them from implementing CLV at 8x for the entire burn?

The rotation speed would be too high for the inner parts @8x.

???
But the burn quality is at it’s highest at the highest rotational speed…

Originally posted by pchilson
???
But the burn quality is at it’s highest at the highest rotational speed…

Remember, the inside edge of the disc travels more slowly under the laser than the outer edge at the same RPM. To get the higher speed toward the center of the disc would require too high a rotation speed. I’m not sure what the actual speed limits will turn out to be, but we may never see more than 4x at the beginning of the disc. Too high an RPM and even if the motor can handle it, you risk shattered media.

fine but the question then is why not cav (noob you can read the faq here ) or p-cav? the velocity stays the same throughout the burn. no worries about discs shredding themselves at that point.

cav burns are sooo much better in cdr than z-clv