Why are all the dual layer DVD recorders 8.5GB?

[Traxan]

I'm looking to upgrade from a single layer DVD burner, but in the stores today, I saw almost all of the drives and all of the blank media was 8.5GB, which is not the full 9.4 GB of storage in a true dual layer disc. Is there any particular reason for this?

 

[bunnyfubbles]

8.5GB IS the capacity. You're confusing double sided with double layered

edit for link to some reading material http://en.wikipedia.org/wiki/DVD

 

[Traxan]

Single layer DVD is 4.7GB. Dual layer, 4.7x2 = 9.4. So I don't follow how you got 8.5 as dual layer.

 

[jdoggg12]

its not the same capacity b/c there are technical difficulties to make the layers the same size - essentially you come out with 2 layers of smaller capacity to make the single sided disc carry more info.

If you think about it, if 4.7 is the max they can get out of a single layer, you'd have to wonder how they could add a 2nd layer w/o affecting the capacity of the original capacity

 

[bunnyfubbles]

reading is your friend

 

[13Gigatons]

Originally posted by: Traxan
Single layer DVD is 4.7GB. Dual layer, 4.7x2 = 9.4. So I don't follow how you got 8.5 as dual layer.

Old dvd-ram had some dual sided discs that were 9.4 but standard dvd burners have always been 8.5GB.

 

[StopSign]

Originally posted by: Traxan
I'm looking to upgrade from a single layer DVD burner, but in the stores today, I saw almost all of the drives and all of the blank media was 8.5GB, which is not the full 9.4 GB of storage in a true dual layer disc. Is there any particular reason for this?

A single layer DVD burner? Wow that must be archaic because I've never seen one.

 

[Praetor]

Originally posted by: StopSign

Originally posted by: Traxan
I'm looking to upgrade from a single layer DVD burner, but in the stores today, I saw almost all of the drives and all of the blank media was 8.5GB, which is not the full 9.4 GB of storage in a true dual layer disc. Is there any particular reason for this?

A single layer DVD burner? Wow that must be archaic because I've never seen one.

Yeah, they came out shortly after the mass dinosaur extinction. Well before your time.