Some good points raised here. With modern systems having such huge RAM buffers for disk access it's certainly much less of a problem.
There's also probably less awareness now about the logical-to-physical translation of disk sectors than in the past. Twenty years ago setting up a typical PC hard disk meant a low-level format in which interleaving (and other factors) had to be decided upon at the outset.
With a slower system and very much more restricted buffer space, changing the interleave the wrong direction could make a huge difference to the access time on a large file.
