What skills do self-taught programmers commonly lack?

> ask someone who's been out of school for a long time the difference between a thread and a process

Quite the contrary: if you're in the industry, the difference between a thread a process should be very hot in your page cache. Understanding why ``system("cd ..");'' won't work is pretty vital.

As for sorting algorithm, you should at least know the big-Oh for a good sorting algorithm. In many specialties of programming, understanding what "amortized" means (e.g., in the context of quicksort's performance) is also important.

Somebody out of school may naively think that quicksort is always good as it's O(log N) or (if they never took an OS class-- and OS classes are, unfortunately, optional in some universities) not fully understand why their code is burning up 100% of a single core in a 8-core machine and leaving the other 7 idle.

On the other hand, I can agree that asking questions which are only answered from memory (i.e., either you know the trick or you don't) that will only be in a recent graduates page cache (e.g., remembering all the rules of a red black tree, or a dynamic programming solution to a classic problem) but can -- and should -- be looked up, doesn't make sense (if I see you implementing a balanced tree in a project without at least cracking CLRS open and looking at existing implementations, I'll have a chat with you...)

As a mostly self taught programmer, I disagree. I think this is an extremely relevant question. There are fields of CS that are generally not encountered when learning programming, in spite of being relevant and often useful. Formal verification and proofs, the lambda calculus, language theory, and other "hard CS" subjects which have real world applications (well, in some fields, anyways) are also relatively rare to run across when self-teaching.

That said, the list in the article is not an especially good one. It might as well have said "The Basics", as far as I'm reading it.

It's really funny, how the LISP bigots say "Lisp", and the numerical experts say "numerics". If you ask those guys what's wrong with CS today, they would say "No Lisp" and "No numerics" respectively.

Even good programmers have huge holes in their knowledge.

This is a good question and actually one that drives most self taught people. This sustained sense of "ooh, I haven't seen that before" helps the self taught learn far more than many formally educated programmers I've met.

I'm self-taught and after a few years in industry, decided to go back to school so I could really accelerate my learning.

I know more than most of my fellow students, due to the few extra years of experience and personal effort, but I definitely had blind spots. It isn't even entire categories of things, but rather little pockets here and there in individual classes.

I have learned a lot, but deciding to get a math BS alongside it has helped the most. I've taken this experience in school as one to soak up as much hard information as possible, so if my personal efforts are any indication, I can see why the combo ends up with a better skills list than either alone.

I've come to really value the stuff that is taught in universities (at a decent enough school anyway). I suspect the longest lived impact of all of this is an ability to read and consume a higher level of information (journals, etc) on a broader variety of topics. It beats blogs, more often than not.