Why would data duplication make a difference for PS3 games when location doesn't affect how fast a blu-ray disc is read?
You're kind of looking at it from the wrong angle. The speed at which the disk
spins is what isn't 'affected'. The rate at which data is read off the disk is a function of where on the disk it is physically located. Data near the outside 'edge' of the disk is whirling past the laser at a much faster rate and is therefore read more quickly than data near the inside ring (even though the disk itself is moving at the same 1x speed). The point in the article from the OP is that some devs just 'dump' the DVD data, only taking up the few gigs that a DVD would hold, and - this is key - data written to all optical formats is written from the
inside out. Meaning if you just take the data structure you were using on the 360 version and put it on a blu-ray disk, you're going to be using (for example) the innermost,
slowest 3-4gb of space on the BD-ROM. Some devs are getting around this by 'padding' the disk with dummy files for a couple dozen gigs, then repeating all of the frequently accessed data (or if they are lazy enough, all the data) on the very last 3-4gb of space, all the way on the outside edge of the disk where it spins (and is read) the fastest.
I hope that helped rather than muddled your understanding.
