Help with software jargon! What is official name of the latest version of iTunes software available for IPad touch 4generation and what is the latest version of operating system is available for iPad touch 4th gen.. I understand I need to load it! ...

There is Operating system software for iPad, iPod and Mac. Is it the same? What is the official name of it? Also, what are the titles of itunes or what are the latest vertion of iTunes software available for iPad, iPod and Mac? Are they the same? For example, iPad touch 4th generation comes blank, there is no software loaded when it is new, you need to load it using PC or Mac, but Mac comes with software already installed and I understand current models of iPad and iPod come with preloaded software! Am I wrong?

What are titles and/or vertions of operating systems and latest software that they need iPad touch 4th generation, iPod touch 4th generation, Mac Book Pro current? Do they need the same operating sytems and/or vertions of iTunes software? I understand previously loaded apps or data could be lost if to update! Please help, Now!