Q:

Calculate hard drive track count

Suppose I have these information of a hard drive : 
Capacity : x Gbytes
Number of cylinder : y 
Number of platters : z (z * 2 surfaces) 
Number of heads : w per platter

How can I calculate the number of tracks of this hard drive? My goal is to calculate the bytes can be stored in one track, assuming each track has the same capacity. 

A:

You probably want to retitle your thread, to indicate you want track count, not track capacity. I spent 15 minutes writing the wrong answer below, before realizing your question is far simpler than I had surmised.
cylinders by definition, are tracks in three dimensions, across all platters. that means that tracks per surface equals cylinders. that means that:
Total Tracks per disk = Cylinders * Surfaces (usually denoted by heads, as most platters have two heads)

---------------------------------My Original Answer--------------------------------------------------------------------------
Well, first off, this is not typically a calculation you would want to make, because it varies by drive type, and is influenced by partition and filesystem concepts like sector size and blocks, such that the number would not directly relate to any practical decision. 
That said, the first thing you need to determine is whether your disk operates using CAV, CLV, or ZBR/Z-CAV layouts. These layouts determine how your drive spins when reading a track, dependent on where the track/cylinder is on the disk in relation to its center and edge. 
CAV and CLV use fixed numbers of bits per track, either by using only a portion of the tracks actual circumference, or by populating bits on the track more densly in the middle and more sparsely at the edge. either approach however wastes a large amount of space. ZBR allows tracks at the edge of holding more bits than tracks at the center, and while it does not use the whole track completely, it does allow the data to be more densely packed across the disk.
a CAV/CLV drive would allow you to calculate track size in bits independent of filesystem constants like sector size (though the manufacturer probably won't provide you all the information required), but with ZBR, the value varies depending on the tracks position in relation to the center of the disk.

