Re: Upgrading NetBSD in-place in a clean way

[Stefano Marinelli <postnet%dragas.dyndns.org@localhost>]

Well, I must say I'm impressed: I thought I wasn't writing anything important, 
still I see that a nice discussion came out. That's one of the biggest and 
strongest points of NetBSD: a great community. Never seen something like that 
before.

>     Correct.  If you don't do that, then the untarred userland may try
> to use features of the new kernel which aren't in the old kernel.

Good. So better reboot after installing the new kernel and modules.

>     When a file is removed, the developer is supposed to flag that
> file as obsolete in the set list.  When the system is built, these
> lines are extracted and the filenames are added to files in
> /var/db/obsolete.  postinstall will read the files in /var/db/obsolete
> and delete any obsolete files that it finds.

This is what I was missing: there is a place where postinstall goes and sees 
what should be deleted. 
Now that I see it, I remember I did it from 5.0.1 to 5.1, and it enumerated 
some files to be removed.

Thank you all for giving many interesting hints!
Stefano