How do you wow second-year students into saying "bare-metal programming is cool!"?

You may not win if you just use words. Instead, give them interesting but challenging exercises to do.

One of the most fun exercises I ever did was to produce a Quine in assembly language. But, instead of producing a textual version of itself, as most Quines do, it produces a running copy in memory and then executes (branches to) that copy. The copy seems to act as if the program is moving through memory. As such, the program is called an Animal. This was once a standard exercise at Dartmouth, and I learned it from faculty and students there.

A more elaborate version will erase the old copy as it creates the new.

The book XINU (XINU Is Not Unix) by Douglas Comer has some interesting things. One of which is a microkernel for an OS.

Unfortunately, this is also one of the skills needed by machine level hackers.

To run such a program you need to assure that the OS won't get in your way, however, so you might need to do this on a simulator.

You can also do interesting things with race conditions and such that are harder to teach in higher level languages.

Forth is very interesting language which can run on bare metal, and also be as high level as you want (I've see a compiler/interpreter of subset of Pascal implemented in 11 pages) and will stretch brain of your students. I know it did mine :-)

And is trivial to code some definitions in Assembly if you want.

Code is incredibly compact, ideal (and still used) for embedded systems.

I would argue the best way to do this is have some demonstrations prepared: things they can build with the tools you're teaching that "look" flashy and exciting. Show some cool programs written in C, demonstrate some sort of Arduino-based program that looks interesting (a relatively simple one I've seen waters plants), something in assembly that looks interesting, and so forth.

Make them say, "I want to build that!" before you give them the tools to build it or things like it.

I may be late to game, but you should target four "wow"s:

• "wow, how small .exe file is!"
• "wow, how fast this program is compared to Python!"
• "wow, and THAT is how it's done!"
• "wow, I'm a hacker now!"

For first one, you should compare compiled sizes of some Go, C++, C and assembler programs which all do a same thing. (Mandelbrot fractal generator in Asm is 61 bytes! Check https://github.com/leto/asmutils/blob/master/src/bonus/mandelbrot.asm, it is runnable)

For second you should show implementation of some number crunching algorithm (beware GPU computing -- try to find example, which can't be sped up with GPUs or optimized by SIMD)

For third one, I like to explain the MBR (even though it is no longer popular). You can put a small command line in 512 bytes of MBR, and load it as floppy in QEMU or from USB on real hardware. It often looks like miracle that you can run code without OS. (http://www.osdever.net/tutorials/view/hello-world-boot-loader)

For fourth one, show how to disassemble code in a disassembler, edit some string, save and run it with new string. Patching binaries no longer will look like mystery.