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I don't know.. many blank disks (..or discs) include both a data capacity and a time capacity.. (700M, 80mins).

I've burnt music (..yes, illegally) on such disks, not mp3 files.. actual audio disks.. so if there was at one time 2 different types of disks, they're hybridized now.

JackScott wrote:<$0.02>
While I'm not confident either way, what bewing says does make sense in that I can remember back in the day when your old audio CD players couldn't play CD-Rs. My portable CD player doesn't read CD-RWs. Just anecdotal evidence, but it would make sense.

Although, it could have something to do with the reflective chemicals used?
</$0.02>

The problem is not such much the reflective chemicals being used so much as incorrect wavelengths being used by the CD's laser.

The "MultiRead Specification", by the Optical Storage Technology Association, answers a lot of this. It says there are four types of CD media: CD-DA, CD-ROM, CD-R, and CD-RW. CD-DA and CD-ROM both use the same laser wavelength to be read. CD-R and CD-RW, aside from using different reflective chemicals, also use different laser wavelengths. The same goes for DVD-RAM, DVD+-RW, and DVD+-R. DVDs also have DVD-Audio and DVD-ROM media types. The MultiRead specification addresses CD and DVD media types, and ensures that MultiRead compatible drives can access all types of media. Of course, this doesn't allow a CD drive to read a DVD, but it does make sure that DVD drives can read all four types of CD media. All drives today should be MultiRead compatible.

The MultiRead Specification is largely meant for computing devices. There is also the MultiPlay Specification, which presents the same kind of information as the MultiRead Specification, but is meant to ensure that DVDs (and CDs) recorded by a computer can be played in a stand-alone DVD (or CD) player.

What JackScott is referring to above would be the MultiPlay Specification.

bewing wrote:I've been a (tiny) computer store owner for 12 years, and my info comes directly from my recordable media distributor (Horizon USA). So I'm willing to directly challenge wikipedia on this one. There are both "audio" and "data" blank CDs, they are different, and the difference is helical vs circular tracks.

But isn't this what sales people is supposed to say? You wouldn't expect them to say that Audio CD's are the same but a lot more expensive.

For the claimed difference a ordinary CD-player would not be able to play a data CD since it would need to have higher rotation speed in order to be able to make up for the cylinder-to-cylinder seek time. There would also need to be extra data indicating where the cylinder begins which is not needed if the groove is spiral. To me it seems that changing the format would break the compatibility.

bewing wrote:I've been a (tiny) computer store owner for 12 years, and my info comes directly from my recordable media distributor (Horizon USA). So I'm willing to directly challenge wikipedia on this one. There are both "audio" and "data" blank CDs, they are different, and the difference is helical vs circular tracks.

could this explain why really old CD players(the first ones?) didn't work with CD-Rs

earlz wrote:could this explain why really old CD players(the first ones?) didn't work with CD-Rs

Read the whole thread before replying :).


JAL

jal wrote:

earlz wrote:could this explain why really old CD players(the first ones?) didn't work with CD-Rs

Read the whole thread before replying .


JAL

my bad.. lol..

btw, as of this moment I am one post behind you rofl

Omg! No one mentioned different algorithms and avoiding starvation?