Barry Shein (email@example.com)
Fri, 19 Dec 86 21:43:15 EST
It seems unfair to cast aspersions at those who have pioneered Network
File Systems as if their implementations were somehow finished or
immutable. Praise should be given to how far the publication of their
efforts has brought us in thinking about the issues (and the
credibility that they are worth thinking about.)
I can think of another major networking protocol which prides itself
on having been put into practice early in its design cycle and
corrected where need be (sometimes radically) based upon concrete use
rather than paper committee meetings. The name escapes me however.
Issues like "file organization" between heterogeneous systems have
been raised for years. I know of no protocol which attempts to solve
this in general (although a few special cases -do- go a long way.)
The last time someone raised this issue in my office I asked him if
this problem had been solved for magnetic tapes yet on his system?
If so, I proposed that I could adapt that solution to FTP (the case
in point at the time) easily enough. Needless to say he walked away
in a huff.
Some of these issues are HARD, very hard! I wouldn't go so far as to
say insoluble (I mean, people do seem to solve them manually) but I
think this difficulty should be considered before saying that XYZ does
not solve this. Proposals for solutions would be most welcome.
I think the problem is that people either want perfect and general
solutions or they throw up their hands entirely. My suspicion is that
the best solution will be the ability to code modules at an
application level to handle the various permutations of file access
methods between systems and let the libraries blossom out of the user
community. Extensibility seems to be the key need here. And practice.
As a more concrete example, why shouldn't FTP allow me to specify
input and output filter programs on both ends, provided as a library
by the systems? The same sort of thing should work for Network File
Systems, although the ability to type files and have these "daemons"
invoked automatically would probably be the right approach. Given a
few years of that I suspect the "standards" would begin to reveal
-Barry Shein, Boston University
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