I've been walking through the QNX documentation, writing (ok, copying) resource managers. Here is where the excellent design of the QNX infrastucture is starting to make itself known. Within a couple of days, I've implemented

• The example single-threaded resource manager (implementing /dev/null)
  
• The exmaple multi-threaded resource manager (implementing /dev/null)
  
• A multi-threaded resource manager with custom io_read and io_write functions, that takes over multiple names in the /dev/ namespace.
  

The next step is, of course, to design and implement a resource manager for the Devantech USBI2C or the Diolan U2C-12. Probably the Diolan, since I've got two student groups using this unit this coming semester.