Recent content by Roffe

FIX is one of the most common protocols, yes. Learn it if you can and want to work with that kind of stuff.

As a general recommendation I'd like to mention Schaum's Outlines for books with lots and lots of solved and unsolved problems. They are available for most of the popular math areas. For a good text book on applied linear algebra (and matrix analysis) may I recommend the book by Carl Meyer.