Speed Issues From CD-ROM

[Guy McLoughlin]

Hi Ruslan,

At 11:11 AM 07/10/2004, Ruslan Zasukhin wrote:

>> There is a huge read speed difference between the inner and outer parts of
>> a CD-ROM disc.
>
>Interesting TIP, Guy!
>
>We need add this somehow to docs/tips
>
>What is difference? 2? 3? 10 times?

It depends on the CD-ROM drive. Some drives rotate the disc at a constant
speed, and some spin the disc faster when reading the inner tracks.

The inner most track has a radius of about 2 cm, and the outer most track
has a radius of about 5.5 cm, which means that the length of tracks are:

Length of a circle = 2 * Pi * radius

Inner most track length = approx 12.5 cm
Outer most track length = 34.5 cm

Which gives us a ratio of about 2.75

So our speed difference is a maxium of 2.75 times faster.

Definitely noticeable when reading data from disc.


- Guy


--------------------------
Guy McLoughlin
New Media Developer
Toronto Ontario Canada
E: theguy at sympatico.ca
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