Hi,



I have an i486 on which was recently upgraded from NetBSD 0.9 to 1.0.
It has a custom card installed for which a 0.9 kernel had been compiled
with its device driver.

I made a few superficial changes to the device driver code  and the 
config files to compile a kernel for the 1.0 version. (since 
some formats and structures have been changed). The system 
boots up to a particular point in the process and then goes back to 
the start of the boot process again.

I have some questions regarding the same :
1. What could be the reasons for such behavior on part of the kernel?
   ( e.g. could an incorrect board address cause  this ?)

2. Would compiling the kernel in debug mode (with the DDB option) in the
   config file help in determining the cause ? Is there any documentation
   on how to use the kernel debugger?

3. Are the changes in the kernel structures documented somewhere?
   ( e.g. there seems to be cfdriver structure used in place of 
     the isa_driver structure.
     Also the config files no longer specify  the "vector"s.
   )




I am new to device drivers (but I hope to learn) so kindly bear with
my questions. Also, please suggest some good books on the subject.



Thanks in advance

Avneesh