Id like for a good text on concurrent programming, I really dont know where to start. Would you be so kind to recommend me one, possibly at the systems level.
Communicating Sequential Processes by Hoare. It's a classic text which outlines a theory for parallel computation.
If you want a book that talks about concurrent programming on the systems level then there are several operating systems books that cover a bit of concurrent programming. The one which I think has the best chapters on this subject is "Operating Systems Concepts" by Silberschatz and Galvin. Stay away from Tannenbaum's book, I didn't like the chapters on concurrent programming at all.
"Principles of Parallel Programming" by Lin and Snyder seems to be a nice book although I haven't read the whole thing. It uses C and should suit your preference for systems programming.
There is also "Unix SYSTEMS Programming" by Robbins and Robbins. It's pretty comprehensive but I haven't read much at all in it so I can't say whether it's good or not.
If you will be using Java then the classic book which contains both theory and practice is Doug Lea's Concurrent Programing in Java: Design Principles and Patterns