Can somebody tell me differences between novelty 35 USC 102 AIA and Old act besides first to file and first to invent?
The changes to section 102 boil down to changing what can be used against an application. Allowing anything filed before you to be used against you is what creates "first to file". We do not literally have a strict first to file in that if you filed last but the first filer "stold" the invention from you, there is a way to try to prove it and win even though you were second to file. Also, if you published your invention in enough detail you can beat someone who filed before you as long as they are claiming almost exactly what you disclosed in your prior publication and as long as you have filed within a year of the publication.
There is an international expansion of what can be used against an application. Before, a publication or a patent counted regardless of the place of the publication but "known or used" was only in this country. Now known or used anywhere can be used against a US application.
Last, US applications that are eventually published or issued can be used against you as of the date of filing. Now foreign applications that have US counterparts or are later filed as PCT applications can also be used as prior art as of their filing date. This increases the amount of so-called "secret" prior art.