Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!apple!oliveb!amiga!cbmvax!jesup
From: jesup@cbmvax.UUCP (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: yet another 1.4 request
Message-ID: <7205@cbmvax.UUCP>
Date: 4 Jul 89 00:46:19 GMT
References: <8906300342.AA12274@postgres.Berkeley.EDU> <398@xdos.UUCP> <7190@cbmvax.UUCP> <402@xdos.UUCP>
Reply-To: jesup@cbmvax.UUCP (Randell Jesup)
Organization: Commodore Technology, West Chester, PA
Lines: 31

In article <402@xdos.UUCP> doug@xdos.UUCP (Doug Merritt) writes:
>In article <7190@cbmvax.UUCP> jesup@cbmvax.UUCP (Randell Jesup) writes:
>>	To totally delete a hardlinked file, you must delete all the links/
>>files.  To totally delete a soft-linked file, you must delete all the softlinks
>>and the original file(link).
>
>I missed this difference in semantics between (potential) AmigaDOS
>soft links and Unix soft links (symbolic links). On Unix, the file goes
>away as soon as you delete the "real" file, regardless of any remaining
>softlinks to it. Deleting soft links never does anything to the original file.

	Sorry, I misunderstood what you were asking.  I thought you were saying
that all the softlinks (themselves) went away when the file they point to
goes away (in Unix), which is not the case.

	Currently, Amiga softlinks will work like Unix softlinks.  Most 
probable implementation is as a file with the "softlink" protection bit set,
and the file containing the string for the link, unless I can figure a way
to worm it into the header (for short strings).  The nice thing about this
is that existing filesystems will magically support softlinks with no new
packets, at the expense slightly slower opens/locks, since the fileheader
must be retrieved to check the bits.  However, the file header block almost
certainly will be cached at that point, since it's needed to lock the file.
(The Dos manual lies when it says locks are much cheaper than opens. :-)

	Opinions?  (ducking from the avalanche of c.s.a.t messages :-)

-- 
Randell Jesup, Commodore Engineering.  Keeper of AmigaDos.
 {uunet|rutgers}!cbmvax!jesup
 Common phrase heard at Amiga Devcon '89: "It's in there!"