On which Mac OS versions could resource forks and named forks be accessed by "file/rsrc" and "file/..namedfork/myfork" paths?
Solution 1:
According to Wikipedia:
From the POSIX interface, the resource fork could be accessed as
filename/..namedfork/rsrcor asfilename/rsrc; the shorter form was deprecated in Mac OS X v10.4 and removed completely in Mac OS X v10.7.
It cites an archived Apple developer document.
10.7 is Lion, of course.