As a human, I have eyes, ears, nose, mouth, a few others senses,
  each with millions of ports. *Every nerve ending is a port. *So
  I wondered, how many does my computer really have? * Well, one
  of the first things that came up on a Google search was about as
  [1]#retro *as it gets; A few years ago, a guy sold a board that
  does the instant 1 second boot-into-basic and showed PEEK and
  POKE commands... which was about the easiest way to access..
  well, anything anywhere on your computer at any time. Anyway,
  even though the info seems old fashioned and out of date,
  computers haven't changed much since the 1980s. Shocking to
  believe. *But.. they haven't. *Better? *Yeah. *Faster? *yeah.
  *More? *Yeah. *Fundamentally the same conceptually? *Yeah. *This
  holds true for just about any device that does "computer-like
  things". It follows the same/similar model to this. *If you
  understand THIS, you, you understand pretty much all general
  purpose computer hardware anywhere in the world.
  http://www.electricalfun.com/WorkbenchFun/Multilabs_BASIC_programming.htm

References

  Visible links
  1. https://plus.google.com/s/%23retro