With the arrival of the new MacBook Pro, the integrated SD card readers also arrived, with the possibility that they give us to boot our brand new MacBook Pro from the memory card, something interesting since we can take a rescue Leopard anywhere.
Yes, una installation of Leopard goes to 6 GB minimum, perhaps a little less by removing languages and PowerPC code, but it is recommended as well indicated is to use an 8 GB card to avoid space problems, and also now the SD are priceless.
Source | Appleism