Subject: Re: AVR port?
To: kevin neff <>
From: Ken Seefried <>
List: tech-ports
Date: 05/31/2002 02:51:41
kevin neff writes: 

> sadly, it seems impossible to create hardware without also creating
> a HUGE software problem.  

Deep insight, are on the path of enlightenment. 

> however, if netbsd could be made to run on a
> system with only a reasonable amount of pain and not too much re-inventing, the
> project could be general enough to be useful and i could continue attending
> classes instead of coding :)

NetBSD is about as portable as you can get, assuming you meet some minimum 
hardware requirements. 

>   + does the processor need be 32-bit? can be 64-bit (and one would assume longer in the future). 

Someone looking for a 16-bit Unix can look at 2BSD, though it is very tied 
to the PDP-11 architecture, esp. the PDP-11s peculiar MMU.  I suppose now 
one could also look at the AT&T V[567] code.  Break out your Lyons book. 

>   is this simply for the convenience of memory addressing?  

I don't understand the question. 

>     does the idea of using multiple 8-bit processors
>     instead of their more expensive counterparts make you laugh?  

Chortle would probably be a better word. 

>   if so, why?

Because the kernel alone wouldn't fit in the address space on an 8-bit 
processor.  Then there is the speed.  We could go from there... 

>   + is a mmu absolutely essential?  

Yes.  Look at uCLinux or some embedded OS if you don't have one. 

>   is virtual memory essential?

VM is implimented by the kernel, so it's implicit. 

>   + how do i get started with a port?  are there some general guidelines?

Download the source, read the docs & mailing lists (referenced from, go from there. 

>   + roughly, how many hours/days/months/years does an average port require? 

No idea...I've been fiddling with a port for months and made no progress 
(but then, I'm not exactly a clueful...:-)  OTOH...the Wasabi guys crank 
them out over cocktails... 

> well, there it is.  thank you for your time.  i'll be looking forward to hearing
> from you!

Best of luck...