Isn't the original CD spec for 74 minutes? I know that in recent years they have stretched it.....??

Yes, I believe you're right. I got confused (amazing how easily that happens) and pulled the 68 number from the standard capacity of 680 MB. 68 minutes, 680 megabytes, 10,936 square millimeters of surface area -- it's all the same thing, isn't it?

And get this -- a CD is almost exactly one cubic inch in volume.

118mm diameter x 1.5mm thick = 16404 mm^3, = 1.001 in^3.

So, a CD plays at roughly one and a quarter hours per cubic inch. Now that's information that's useful to know!

tanstaafl.