How does an optic-mechanical laser read and send binary bytes to a CPU? Thid greatly concerns physics, since a more refined version of my title will be rehearsed below:
How is the physical structure of the mechanical eye use a laser to read binary bits held on an optical track that is basically smaller than one nano meter in size?
how does the laser do this?
 A: The size of the tracks is comparable to a micrometer.
The distance of the laser from the axis of the rotation is regulated by the "tracking system" which has a "tracking motor" in the outer part of it, driving the "laser pickup". See e.g.

http://www.bcae1.com/cdplayer.htm
http://electronics.howstuffworks.com/cd6.htm

The motor is an ordinary DC (direct current) motor. With appropriate wheels and gears (wheels with different numbers of teeth may increase or reduce the velocity), you could easily get a micrometer precision even if you started with a rather large motor. But these motors are already small to start with. 
An interesting subtlety is that the CD player wants to keep the velocity, and not the angular velocity, constant so the spindle (the fast "drive motor" in the middle) actually adjusts its angular velocity depending on the distance of the laser from the axis. 
Of course that these mechanical parts aren't allowed to have generic defects in the shape (on the "wheels" etc.) that would be as large as a micrometer. The general portion of engineering that deals with positioning objects at the micrometer precision is known as precision (or fine) mechanics.
