Somewhere i heard the term 'Scratchbox2'. Why this is used? what is the exact meaning of this? What is the advantages over Scratchbox 1?
Scratchbox is cross-compilation suite.
It looks like Scratchbox 2 (sbox2) is new version of Scratchbox 1, maintained by Nokia for Maemo development. You can use it for general cross-compilation too. It is a fork of Scratchbox.
Main advantage of Scratchbox 2 is a more elegant approach on some corner cases. It also performs better, as it uses native tools whenever possible, and otherwise emulation. For Scratchbox 2 you don't have to modify any host tools. Scratchbox 1 may require some changes and recompilations.