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A primer on CLV vs. CAV
Authored by: Lectrick on Oct 27, '06 08:34:02AM
http://en.wikipedia.org/wiki/Constant_linear_velocity

CD's use CLV (Constant Linear Velocity) which basically means that the same amount of track per second (1.2 meters/s) passes under the read head no matter where the head is on the CD. So I'm not sure why iTunes rips faster towards the end of the CD.

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In /dev/null, no one can hear you scream

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A primer on CLV vs. CAV
Authored by: j-beda on Oct 27, '06 09:35:15AM

<I>CD's use CLV (Constant Linear Velocity)</><P>
Deeper digging in wikipedia shows that audio playback uses CLV, but it looks like high speed CD-ROM drives use "constant angular velocity" or some sort of "zoned" CLV, thus allowing for higher data rates for data on the outer tracks of the CD.



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A primer on CLV vs. CAV
Authored by: dethbunny on Oct 27, '06 02:17:57PM

The disc is recorded in CLV, but most any high-speed drive reads (and likely writes) in CAV. The limiting factor for a high-speed drive is vibration caused by disc balance issues. The more RPMs, the more the disc will wobble. The drive spins as fast as it can while still reading data accurately.

As the track is physically longer toward the outside of the disc, more data can be read per revolution. Since the drive is always spinning as fast as it possibly can and still read reliably, more track, and thus more data, goes by the read head toward the outside. Thus you get much better data rates toward the end of the disc than toward the beginning.



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