No, but you might well wnat to a couple of <time_units> in the future. And then find there's no way that you can. This reminds me of the well-known comment 'The problem with linux is that you have to learn how to recompile the kernel'. My reply to that is 'No, you _can_ recompile the kernel if you want to, but you don''t _have_ to. The supplied one works fine'. So to go back to your comment, even if the processor is a big board of TTL, you don't _have_ to understnad it, or look at the schematic, or anything if you don't want to. You can treat it as a black box and write programs for it. A board of TTL can have the same wort of user- or programmer- level description as a custom chip. But if you want to get inside, you can. Anyway, we have no idea waht the OP's kid wants to do :-) Indeed it is. And my experience (possibly biased by the fact that I was a hardware hacker before I even saw a computer) is that most beginner-level books _are_ over-simplified. -tony