Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!mcf!mibte!gamma!towernet!pyuxp!pyuxd!pyuxf!asg
From: asg@pyuxf.UUCP (alan geller)
Newsgroups: comp.sys.mac.programmer
Subject: Re: System 7.0 & Aliases
Summary: Enough, already
Message-ID: <561@pyuxf.UUCP>
Date: 30 Aug 89 23:22:12 GMT
References: <3948@internal.Apple.COM>
Organization: Bellcore, Livingston, NJ
Lines: 38


OK, OK, OK.  So far I've read dozens of complaints about Apple implementing
file aliases using 'file ids'.  Many of the complaints have mentioned how
terrible this is, especially compared to what Unix does.

WHAT DO YOU THINK AN INODE IS, PEOPLE?!?!?!?!?!

That is, Unix directory entries contain a file name and an inode number.
The inode number is an index into the filesystem's inode table, which is
a big array of inode data structures that live at the front (usually) of
the filesystem.  The inodes contain the actual file block pointers.  That
is, if you have two files, A and B, which share an inode, and use an editor
on A which renames A to A.bak and creates a new file named A with the results
of your edit, ...
	A.bak and B are the same (share an inode), and
	A is totally different!!!

Isn't this exactly what Apple is talking about?

Now, if this is really such a problem, why hasn't it been such a problem
in Unix?  Sure, for situations such as the above, you (the programmer) have 
to think ahead, so that you (the user) don't get confused:  you have to copy
A to A.bak, truncate A, and then write the new file out to A, thus maintaining
the link between A and B.  And apparently Apple is even going to give us a
call that will flip two file's contents, so that all you have to do is write
a new file and flip the new A and the old A!

Let's look at this another way.  Given the ability to rename files, so that
pathnames are not sufficient for permanently identifying files; given that
file icons can be moved, so screen icon location is no good; files can move
from folder to folder, so folder plus relative position in folder is no good;
and so on, what is a better way to permanently identify the 'file' that is 
shared between two different path aliases?  Answer that, and THEN flame --
or write the great American OS, instead.

Alan Geller
Bellcore
I have no association with Apple, other than as a very satisfied user.