Actually, that is incorrect. The Old Testament was not written in no 600 BC. The Old Testament is a "compilation" of writings from Adam through to right up to the time of the Greeks...
And Adam wrote ...?
The first five book series of the Bible were a compilation of historic writings on stone, by the forefathers: starting with Adam, Seth, Noah..., up to the writings of Moses(the Law/Torah), and the chosen high priests and scribes put these together...
And your evidence for the existence of those stone writings is ...?
Later, after papyrus was invented in Babylon...
And your evidence that papyrus was invented or even used in Babylon is ...?
The original Scriptures are not fallible, they are tried and true...
And where is it that the original scriptures can be found ...?
Your evidence that they were infallible is...?
Aslan is not a Tame Lion