Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!cornell!vax5!jhc
From: jhc@vax5.CIT.CORNELL.EDU
Newsgroups: comp.unix.questions
Subject: Re: File Write Permission Rules
Keywords: file write permission rules
Message-ID: <17999@vax5.CIT.CORNELL.EDU>
Date: 22 Feb 89 04:22:13 GMT
References: <306@wubios.wustl.edu> <1177@ubu.warwick.UUCP> <5714@bsu-cs.UUCP>
Sender: news@vax5.CIT.CORNELL.EDU
Reply-To: jhc@vax5.cit.cornell.edu (James H. Cloos, Jr.)
Organization: Cornell Information Technologies, Ithaca, NY 14853
Lines: 53

In article <5714@bsu-cs.UUCP> dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
>In article <1177@ubu.warwick.UUCP> mirk@uk.ac.warwick.cs (Mike Taylor) writes:
>[the unix permissions scheme is intuitive because a directory
>is a list of files]
>
>There is still a flaw.
>
>If a directory is like the card catalog in a library, and the files
>themselves are like the books, then it is counter-intuitive that, when
>somebody vandalizes the card catalog, all the books are destroyed too.
>
>In UNIX, the existence of a file under normal circumstances is nearly
>synonymous with the existence of its directory entry.  In a sense the
>directory entry represents the file to the user, since he cannot look
>at the file in any other way.  It *is* counterintuitive that a
>read-only file cannot be written to but can still be deleted.
>
>Thank heavens for the sticky bit on directories.  It came just in time,
>and does invalidate much of the criticism.

It would seem to me, that if you make the analogy that Rahul makes, you need
to go further and make the library one where the books are fetched for you
by library staff, rather than one where the stacks have public access.

Further, the gofers are somewhat dull, in that they can only find the books
if someone tells them what the catalog numbers are--especially as (if this
really _is_ the case) the books just might not have their catalog number
written on themselves.  Ie., PS344.A3S4 means something on the order of: 
go to floor PS, find room 344, go to stack row A, count up 3 shelves, find
section S of said shelf, and choos the 4th slot.)

Of course, the professional librarians can root thru the stacks and
recatalog all of the books; this takes considerable time and is quite an
annoyance--especially if somebody has a black-box that, when activated, will
expand itself into a building exacltly like the library was at a certain
point in time before the catalog was messed with. ;^)

[By making the librarians capable of recataloging the files, I make the
assumption that there exists somewhere a utility for UNIX that resembles the
Mac's Fedit, or Norton for the PC's,...]

Disclaimer:  I'm makeing a couple of assumption on how the UNIX file system
works, but I think that my assumptions are close to correct.  (Although the
6+ step process of maping a US Lib. of Congress catalog number to a book was
not supposed to indicate the there are that many steps involved in UNIX ;^)

-JimC
--
James H. Cloos, Jr.          "Entropy isn't what it used to be."
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