Drivers for PD-8 hard drives

[bchurch@oucsace.cs.ohiou.edu (Robert Church)]

I need to rewrite the driver for my Quark Hard Drive. The problem is that 
I don't know where to start. All my programming up till now has involved
using the existing drivers and the MLI. Are there any good texts, etc. for
getting started on something like this? I have a good dissasembler to take the
old driver apart with but it's slow going if you have no idea what you're looking for.
This would be under Prodos 8, by the way.

Thanks,
Bob Church