Inside the surprisingly few bytes above, some currently unnamed authors implemented a whole control of the printer/plotter's hardware, full serial IEC communication stack, and on top of those they still managed to squeeze a fairly complete font with 96 vector characters in! An example of software engineering craftsmanship at the level we don't see all too often.
For those curious, the size of the ROM data is 4139 bytes. Amazing that it contains a vector font in addition to the executable.
This is really cool stuff and I honestly would love to do things like this in the future. I am heading off to college this year and I guess I would like to know how one can start learning about hardware hacking in general. Does HN have any suggestions on classes, videos, etc?
Sorry if this isn't completely on topic, but I feel this has to be one of the best places to gain knowledge from.
The best way is to just do it. Seriously. Abstract learning only gets you so far in this context. Pick a project and do it. Along the way you'll need certain skills and knowledge. As you research them you'll find others you need as well. Lather. Rinse. Repeat.
This is the exact advice I would give, minus one key thing -- don't be scared of the hard stuff. So many people are held back by fear of things they don't understand. Learn to run toward it rather than away from it, and you'll do very, very well.
I'd recommend you read "Hacking the Xbox" by Andy Huang, it's a free ebook that explains a lot of the basics of hardware hacking and reverse-engineering, and then goes on to demonstrate what he did on the Xbox. Very insightful and fascinating read.
They have a great PDF that explains things from the ground up. You end up with a homemade "Arduino" that you can use as the basis for additional projects.
For those curious, the size of the ROM data is 4139 bytes. Amazing that it contains a vector font in addition to the executable.