Question: What is the max file size that SAS software can successfully read.
(without considering hardware limit)

Thanks in advance.

Answer: 
To quote a recently running TV commercial, the answer is "infinity plus 1".

SAS does not have any limitation on the size of a file during read operations, although it's possible you might run into a limit on the number of observations written to a new SAS data set. On a 64-bit system, that would be 2\*\*63-1, about 9.2 quintillion observations. You are more likely to run out of disk space.
Reading from a text file, you are limited by the OS typically. Windows allows 1 million characters wide, for example, although SAS can theoretically handle a lrecl of over that.

In general, if you're asking about observations, you will be disk space limited before you are limited by anything else. I've seen a file created that were denominated in PB (petabytes, or 1 thousand terabytes) when on a compressed volume.