The fundamental difference between Intel's latest Pentium chip and Maytag's lowliest washing-machine controller is the pattern of interconnections. The essential elements of logic are the same. Both products incorporate AND gates, OR gates, and flip-flops. It is the interconnections (and the number of elements) that make the difference.
Whenever you start a new product design, spend some time thinking about the interconnections. By focusing your attention on the interconnections, rather than the elements of logic themselves, you can anticipate difficult bus, connector, and cable problems before the design gets under way. Having seen more than one major project canned late in its development after a losing a long fight with an uncooperative bus architecture, I am convinced that investing time in the interconnection problem early in the cycle pays large dividends later.
Unfortunately, professors in college do not always teach digital design with interconnections in mind. For example, many freshly trained engineers intimately understand the physics of FET operation, the quasistatic distribution of charge underneath a gate, and the complex processes you use to form and etch silicon components. When you ask these same engineers how much current flows in a transmission line, your question is often met with a blank stare.
Earth to college: "It's nice to know about silicon-device physics, but a working knowledge of transmission lines, mutual inductance, and the flow of returning signal current will help your students better understand ringing, crosstalk, and ground bounce."
Lest you underestimate the importance of the flow of current, I would like to point out that charged particles at rest serve absolutely no useful purpose. You can store charged particles in a Leyden jar, or you can watch them attract pith balls, but you can't really do anything with charged particles until you put them in motion. What matters in real-world applications is the movement of charged particles (current), not merely their static existence.
Consider the top two killer applications for electricity: telecommunications and electric power. Both involve the transmission of electrical energy. At all scales of operation—from the global-telecommunication and power infrastructure to the wiring inside an IC—the same principle holds true: Interconnections matter.
Just look within the skins of a PC. Do you see logic gates? Do you see software? No, you see packages, connectors, component leads, pc boards, wiring, and power supplies. You see what is mostly there: the infrastructure of communication and power.
Inside the ICs, what do you see? Do you see underneath the gate of an individual FET? Do you see where logical operations are actually taking place? No, you see mainly sources and drains, polyimide and metal, the mechanics of interconnecting one FET to the next: the infrastructure of communication and power.
Most digital hardware is devoted to interconnections. The interconnections, by hooking together the logical operatives, define the functions of a digital machine. The interconnections then communicate those functions to the outside world. When you look at a digital machine, if you are not looking at the interconnections, you are missing one of the most important parts of the structure.
Next time you push "start" on your washing machine, take a moment to appreciate all the mechanical, packaging, and signal-integrity specialists that make digital products possible.