>>Is 8MB DiskOnChip enough and if not how many space I need.
>>    
>>
>Enough for what? It's enough for simple routing/firewalling but if you need more features, I'd suggest you at least twice the size. 
>Are 8MB modules avaliable anymore ? I cant find anything <64M now a days.
>Anyway, why do you need it since you're gonna use a HD ?
>  
>
In fact I have to test netBSD for a futur design,  and the only card I 
have is an old card with only 8MB DOC. Of course I can use a HD (128MB), 
but I want to learn how to install netBSD on DiskOnChip, because I do 
that with linux and it was little bit difficult !!

I need this pc104 for make a tester (for plane!) and I want an 
application to communicate between operator with a basic graphic 
interface (ncurse ?). And I have to communicate with the test card with 
USB (HID).

For the the end designed equipement I can't use HD, because I have lots 
of constraints (chock, temperature,...) and I think DiskOnChip is the 
best way.