jbuck@epimass.EPI.COM (Joe Buck) (02/19/88)
In article <3379@killer.UUCP> jfh@killer.UUCP (The Beach Bum) writes: >In article <23012@ucbvax.BERKELEY.EDU> fair@ucbarpa.Berkeley.EDU (Erik E. Fair) writes: >>Netnews uses UNIX "hard" links to link the multiple instantiations >>of a news article into the multiple newsgroup directories. Netnews >>is most certainly NOT making N copies of an article for appearance >>in N newsgroups, except on VMS systems, under Eunice (but then, >>they deserve to lose). > >There was an interesting mis-feature in VMS prior to version 3.0 which >allowed (and may still allow) creating something like hard links by >judicious use of COPY/OVERLAY and a few other simple commands to create >a fake directory (which was then copied onto the real directory). Hard links can be created on VMS just as on Unix by manipulating directory entries directly. I considered doing this when I did the Eunice news code, but it's very risky; you might end up with a corrupted disk or one that's full of unreachable files. VMS has a "remove" call that deletes a directory entry (possibly leaving an unreachable file) as well as a "delete" call that removes both a file and a directory entry (possibly leaving other directory entries pointing off into space). But there is nothing that counts the number of names a file has, so the Unix behavior (file disappears when the last link is gone) is difficult to emulate). Check out SET FILE/ENTER and SET FILE/REMOVE. Carefully! -- - Joe Buck {uunet,ucbvax,sun,<smart-site>}!epimass.epi.com!jbuck Old Internet mailers: jbuck%epimass.epi.com@uunet.uu.net