Apple systems have always used different key combinations to perform different tasks, just like all computer makers. However, finding those key combinations has always been an arduous task – they don’t come right out and tell you in the manual how to do some of these.
A reader asks: "Can someone comment on the legality of using my brother's old Snow Leopard DVD to install OS X? My brother has Lion, so why can't he choose to give it to me? It doesn't violate Apple's 1 license per 1 computer policy."