Can you please provide a source for your claims about Apple <i>religiously avoiding</i> bit fiddling?<p>Because Snow Leopard is <i>all about</i> using some really crafty and serious bit fiddling + Resource Forks to improve performance and decrease size.<p>If you haven't read John Siracusa's <i>excellent</i> report on Snow Leopard, have a look at this page of his review: <a href="http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars/3#" rel="nofollow">http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.a...</a><p>While a lot of what he says is about compression, but pay special attention to what John says about <i>the entire contents of files</i> being stored in extended attributes in order to boost performance and lower file size... and Mail archives being stored in Resource Forks... and much, much more.<p>And I never mention bundles anywhere - they're a higher level construct independent of the FS.