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From: jcampbell@mrfort.DEC (Jon Campbell)
Newsgroups: net.unix-wizards
Subject: more on file \"attributes\"
Message-ID: <3398@decwrl.UUCP>
Date: Thu, 1-Aug-85 10:38:46 EDT
Article-I.D.: decwrl.3398
Posted: Thu Aug  1 10:38:46 1985
Date-Received: Sat, 3-Aug-85 04:13:15 EDT
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Organization: Digital Equipment Corporation
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Well, my mailbox runneth over with mail telling me how I've struck
at the heart of UNIX by suggesting file attributes. I think perhaps
I have presented the problem (and its possible solution) in the wrong
light.
 
What many users have suggested is that I put a "file header" at the
beginning of each file. This seems like a reasonable approach, except
that existing FORTRANs do not put such cruft at the beginning of files
now. So we have a skew problem. What I was suggesting, though it might
have not been clear, is an "invisible" file header, one which you look
at in a slightly different way than the real data (the bytes in the file).
Perhaps this could be by using a negative byte address in the file, perhaps
some other way. I'm not particularly interested in the way it might be done,
except that it cannot be part of the actual data and it cannot be a separate
file.
 
There are many such operating systems (which have file information in
invisible or hidden headers) around, such as the ATEX text-processing
system used in many newspapers. Ordinary programs and utilities need
not ever look at the invisible header if they are interested in the
data only.
 
I suggested that it be part of the "file information block" (i.e.,
the filename, creation date, and size) because that is a convenient
way to have it copied transparently when you make a copy of the file
or rename the file.
 
I am not suggesting changing the way that the vast majority of UNIX
utilities and user programs currently look at files, nor suggesting
any changes to them. I am suggesting that we give a data-handle, if
you will, for those programs and utilities which care to use the
"attributes". There is no loss of performance, no restrictions placed
on file usage, and very small extra disk space used.
 
I think that you folks who are having a look at creating UNIX utilities
which can do serious data manipulation, read magtapes from "foreign"
operating systems and munge it (without having to read the ANSI
magtape header files by hand), or write utilities which can look at
different files without knowing a priori the file format, will
recognize the problem that I am trying to address. I am not trying
to "strike at the heart" of UNIX; I am letting you know that there
is a problem to be solved that cannot be solved easily.
 
Thanks for all of your feedback. I am looking forward for more.
 
					Thanks,
					Jon Campbell
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