Device Driver - before I start

[Richard Kaestner]

Is there a helping hand to give me some advice where / how to start?

I want:
- a "pseudo device", which collects every now and then data from an external
  box via serial line (/dev/cuaa1)
  Box-Status and some more information shoud be readable,
  whichever Commands have to be sent to the Box could be done via ioctl
- using FreeBSD 4.10 ( going to 5.x later)
- I am currently reading:
  FreeBSD Handbook and Developers Handbook
  Daemonnews: Oct 2000: KLD example / Tutorial
  /usr/src/share/examples/driver/make...
  ( and McKusik's Design ...)
- And finally: this is going to be my first Unix-Driver ...
  (although, I have some experience in low-level programming)

I need Infos on:
- is there a "better" (or "more preferred") way than written above?
- is there a "simple example driver" doing similar things
- actually, can I simply access /dev/cuaa1 from "inside" a driver ?
  (suppose, I should not ...)
- or should I simply / better stay with a daemon ?

thanks in advance for hints!

-- 
Mit freundlichen Grüßen

Richard Kästner
EDV-Beratung
Woerthgasse 17
2500 Baden
Austria