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what should RnRS be all about?
re: George Carrette has suggested that we could make a FASLOAD format
which would be portable between machines and implementations. I am
not sure how far this can go, but for structures composed of vectors,
lists, symbols, booleans, strings, characters, and numbers it
certainly seems doable.
Such a FASLOAD format would greatly enhance the ability to do surgery,
even if it meant moving to a new machine (brain transplant).
Lucid's Common Lisp product is built around an optimized, machine
independent FASLOAD format. The *only* dependencies in the fasl files
are (alas, this is always true) the major development version number
of which there have been about three during the lifetime of the company,
and the actual content of the bit-vectors that constitute the
instruction streams for procedures.
This fasl format was seriously used in a kind of kludgy RPC between
some multi-procesor systems once.
The port/machine independence has been of enormous help in debugging
some port that isn't quite working. We just "cross-compile" into
the binary for machine Y, and then load it into an image running on
machine X, where it may be inspected and poked (and even edited!) like
any other first-class object.
On long-lived data, such as 20 years or so: this may be possible in
the world of mil-spec, ruggedized COBOL processors. But in the world
of engineering workstations (and the PC's that are nibbling at their
heels) it seems that very few models survive more than about three
to five years, after which they become obsolete and are unsupported
by their manufacturer. Most individual units "die out" very quickly
after that (although there is a company in San Jose that specializes
is doing after-market support for obsolete computers.) Witness the
revolutionalry Sun-3 computer from Sun Microsystems. When first
introduced (in about January 86?) it was the first reasonable personal
workstation that could compete in speed with the propietary archtectures
like the Symbolics 3600. And in about 1990 or so, Sun dropped support
for it and, according to the New York Times, decided to put "All their
arrows behind one woodenhead" (or, was it all their wood . . .).
Anyhooo, for now, the SPARCitecture lives.
But for 20 more years . . . ???
-- JonL --