I'm in 100% agreement with Thaddy here, but I think one point is worth amplifying. Things that "look like files" in the /proc and /sys trees are actually generated on demand by the kernel, the special filesystems are just a convenient abstraction that allows kernel (and individual process) state to be queried.
Back when Linux distreaux were somewhat less polished, it was possible to find oneself in an odd state where the kernel was running but /proc wasn't mounted. Because this was such an important interface to the kernel, when this happened utilities such as ps and top couldn't return any useful information.
MarkMLl