Starting "Position" of a CD Rom Disk

[Brad]

Hi,

I have been told that a data cd (also audio cd) is
first "read" from the middle track. Another person told me
that it is first "read" from the inside track. I always thought
it was first read from the outside (near the edge) track.

Can someone, who really knows, tell me where the
first "reading" (when you insert a CD) takes place?

Thanks in advance, Brad

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[carl0s]

Hi,

I have been told that a data cd (also audio cd) is
first "read" from the middle track. Another person told me
that it is first "read" from the inside track. I always thought
it was first read from the outside (near the edge) track.

It is the inside. For this reason the performance of reading or writing gets
better as you nearer the end of the CD.

 

[Allodoxaphobia]

It is the inside. For this reason the performance of reading or writing gets
better as you nearer the end of the CD.

For another reason, the CD can tell the device what size it is.
That-a-way, a CD drive can read 3" CD's, or even those dinky
business-card-sized CD's.

Jonesy

 

[Sam Goldwasser]

It is the inside. For this reason the performance of reading or writing gets
better as you nearer the end of the CD.

Not necessarily.

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[carl0s]

Not necessarily.

Am I correct in thinking that up until around about 32-speed drives, they
would vary the spinning speed to maintain a precise transfer rate?

 

[James Sweet]

Am I correct in thinking that up until around about 32-speed drives, they
would vary the spinning speed to maintain a precise transfer rate?

Yes, the early drives and audio CD players were Constant Linear Velocity
(CLV) where the RPM varies to keep the data rate constant while faster
drives are Constant Angular Velocity (CAV) where the RPM is steady but
the data rate increases as you near the outer edge of the disc.