A Hardware Threepack

Johnath writes: "This just happens to be a great time to be a hardware junkie. For those interested in learning more about the metal under their PC's hood, Tom's Hardware has a great intro to PCB manufacturing, Ars Technica has recently written an architectural study of the P4, and ExtremeTech has a decent look at the South Bridge." The circuit board article is really good - explains it better than the textbooks I've seen.

Comments

Solder mask vs. conformal coating

[Animats]

They're two different things. A solder mask is a (usually green) layer that covers the parts of the board that don't need solder. This allows closer spacing between traces, because the solder mask protects them from solder bridges. Solder masks are for wave-soldered boards with through-hole components; surface mount boards use a different technique.

A conformal coating is a thick, usually clear, protective layer that goes on after the components are inserted and soldered. It protects the board against water and other environmental hazards. Boards in computers usually don't get a conformal coating, but automotive, marine, and aerospace electronics usually do.
You can get conformal coatings in spray cans and do it yourself, which can be useful if you're building electronics that has to survive wet environments.