I am a programmer that knows what a MOSFET is.  I had to know in order to pass intro to digital logic.<p>They are 4-connection devices, but <i>usually</i> source is connected to body.  They come in n-type and p-type, and <i>usually</i> operate in enhancement mode, where the channel between source and drain opens when the signals to gate and body are different.  With those, you can either pass a weak digital 0 or a strong 1, or a weak 1 and a strong 0, so in order to produce a digital output that has strong 0 or strong 1 for every possible input and doesn&#x27;t &quot;leak&quot; power, you can combine the result of the 0 logic with the result of the 1 logic.  Hence the term <i>complimentary</i> MOS (CMOS).<p>So a CMOS NOT gate has 2 MOSFETs: one n-type, and one p-type.  A NAND gate has 4 MOSFETs, 2 of each type: the zero logic connected in series, and the one logic in parallel.<p>This knowledge--that I never really needed to write software for a living--was all building up to constructing a basic ALU using digital logic gate chips on breadboards with DIP input switches, LED outputs, and a manually-switched clock signal.  I&#x27;m glad that I know it, but I&#x27;m mostly willing to trust the folks at Intel and AMD to do 64-bit ADD, SUB, MUL, DIV, and MOD correctly on integers.<p>Should I ever really need to, I could <i>probably</i> pick apart a very high-resolution image of a CMOS chip.  I wouldn&#x27;t necessarily be able to design such a chip, but I could <i>eventually</i> tell you what it does.  And knowing what I know, I also have some idea that manipulating 32-bit floats on an 8-bit integer ALU is going to require <i>much</i> more complexity in the microcode or software.<p>That level of detail is not necessary for me to know that shaving with a laser is practically untenable in 2015.  It&#x27;s the sort of thing that I might expect in sci-fi as a hand-wavey sort of marker of a futuristic setting, but it will probably never happen.  It&#x27;s more likely that we&#x27;ll have an epigenetic treatment that simply instructs follicle cells to either stop growing hair entirely, or to make the hairs they grow be pigmentless and reduced in diameter.  Until then, steel blades will continue to work just fine.<p>Even there, I am still skeptical that five parallel blades are really better than one.  So to me, when you propose that I shave with a laser, I will roll my eyes at you just as hard as if you suggested that I pay 40% more per shave to add a <i>sixth</i> blade <i>and a magnet</i> to my razor.  Human hair is not evolving defenses against older shaving technology.  You can still scrape your face with knapped flint if you needed to.<p>If people are stupid about laser shaves, it may be because they have been well primed for this nonsense by the advertisements of Schick and Gillette and their flexy, bendy, swivelling, lubricating, blinking, bleeping, 20-bladed shaving heads.