Questions like: what determines printer resolution?

[JimmyD]

Hi

I'd like to build a 3D printer using existing electronics, preferably open source software and hardware. I see a lot of printers out there use RepRap controller/driver boards. I have a few questions I was hoping someone could help me with to see if they would work for me:

* What is the biggest determinant of a printer's resolution? Assuming I want to use stepper motors instead of servos, is it the number of positions the motors have? I would imagine the size of the nozzle and the software would also have an impact.

* Is it common for a printer without closed-loop error correction to have errors compound over the span of a print? Is there anything that can be done about it?

* Speaking of software, if a printer's hardware theoretically had the capability to print nearly infinitely small resolution, how small of an increment of movement can G-code specify to it?

* Can anyone recommend any good controller boards I could use to make a printer that could print down to 50 microns? How about down to 10?

* I have found only 1 example out there of someone who used a Raspberry Pi as the "brain" in their printer. Does anyone know of any others? I'd like to

Thanks very much for any help. I'm really looking forward to understanding how to make an awesome printer!