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I cannot make heads or tails of the ATA standards. More specifically, I cannot find the information from tutorials and example code in the standards themselves (ie, the draft versions from t13.org).

On a more general note, I'm trying to understand the various official documentation out there instead of relying on example/tutorial code. I want to learn how to "read documentation" which is odd but seems to be a good skill to have especially since it appears to require too much effort to get people to write easy-to-understand documentation.

Most of those documentations that you are referring to are Technical Documentations or documents. I had a lot of problems reading ATA documentations also. What helped me understand those documentations better was getting my hands dirty with the actual coding process. When you are merely reading a document, you don't know what to expect from it. Once you start writing a program and you get stuck, you know exactly what you are looking for in the document. That's when it starts to make sense.