On 9/9/2014 8:51 AM, Tom Fine wrote:
>
> According to Philips own design engineers (who designed the physical
> disc), there ended up being a 5" diameter mandate and that's how the
> time length got decided. It's that simple.

5" was also an attractive size because the player for a 5" disc would 
fit into the standard cutout in a car's dashboard. At the time many cars 
had radio/cassette players, and the Compact Disc was intended as a 
replacement for the Compact Cassette, to use the formal names for each 
format.

Peace,
Paul