FreeBSD file system example and question

[Lowell Gilbert]

Marcin <marcin at desk.pl> writes:

> Hello, where can i find information or examples of how to write a file system for FreeBSD, apart from /usr/src/sys/* and /usr/share/man/*?

The Architecure Handbook. (/usr/share/doc/en/arch-handbook)

The old McKusick book (/usr/share/doc/en/design-44bsd)
 
The new McKusick book (ISBN 0-201-70245-2)

> What is vnode_if.h for? Why is it generated for every fs module if it is the same every time? I tried to google for the answer but found nothing. Only a note on Darwin's dev site.

If I recall correctly that was a Sun-ism originally.
It can be useful as a cross-platform tool, but I don't know if anyone
is using it that way these days.