The Extension of MIME Content-Types to a New Medium
RFC 1437

Document Type RFC - Informational (April 1993; No errata)
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Network Working Group                                     N. Borenstein
Request for Comments: 1437                                     Bellcore
                                                             M. Linimon
                                       Lonesome Dove Computing Services
                                                           1 April 1993

          The Extension of MIME Content-Types to a New Medium

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

Abstract

   A previous document, RFC 1341, defines a format and general framework
   for the representation of a wide variety of data types in Internet
   mail.  This document defines one particular type of MIME data, the
   matter-transport/sentient-life-form type.  The matter-
   transport/sentient-life-form MIME type is intended to facilitate the
   wider interoperation of electronic mail messages that include entire
   sentient life forms, such as human beings.

   Other informally proposed subtypes, such as "non-sentient-life-form",
   "non-sentient-non-life-form", and the orthogonally necessary but
   nevertheless puzzling "sentient-non-life-form", are not described in
   this memo.

The matter-transport/sentient-life-form MIME type

   In order to promote the wider interoperability of life-bearing email,
   this document defines a new MIME content-type, "matter-transport",
   and for an initial subtype, "sentient-life-form".  This subtype was
   designed to meet the following criteria:

      1.  The syntax must be extremely simple to parse, to minimize the
      risk of accidental death due to misinterpretation of the standard.

      2.  The data format must be extremely robust, with redundancy to
      ensure that individual life forms will survive and be
      reconstituted in such a form as to be nearly indistinguishable
      from their initial state, no matter how many bizarre email
      gateways are encountered in transit.

      3.  The syntax must be extensible to allow for the description of
      all yet-undiscovered aspects of life forms which will be required

Borenstein & Linimon                                            [Page 1]
RFC 1437          MIME Content-Types for a New Medium       1 April 1993

      for the transport of non-human species (e.g. dolphins, Klingons,
      or politicians).

      4.  The syntax must be compatible with SGML, so that with an
      appropriate DTD (Document Type Definition -- the standard
      mechanism for defining a document type using SGML), a general SGML
      parser could be written to parse the data structure and produce
      directives to a lifeform-reconstitution mechanism. However,
      despite this compatibility, the syntax will most likely be far
      simpler than that of full SGML (so that no SGML knowledge is
      required in order to implement it), since it is anticipated that
      the full complexities of SGML will not be necessary for the
      description of even arbitrarily complex organic life forms.

   The syntax of the new content-type is very simple, and indeed makes
   considerable sacrifice of efficiency in the interest of simplicity.
   It is assumed to describe a three-dimensional rectangular solid, with
   the height, width, and depth (calibrated in centimeters) specified as
   parameters on the content-type line.  (In general, this should be a
   cube that completely contains the life form being transported; but,
   where high bandwidth is not available, a somewhat smaller cube can be
   used, provided that facilities are known to be available at the
   recipient's end to administer the medical first aid that could be
   necessary if an individual is reconstituted sans some of its
   extremities.)  A fourth parameter gives the resolution of the matter
   scan, calibrated in Angstroms.  Thus, the following Content-type
   value:

      Content-type:  matter-transport/sentient-life-form;
              height = 200; width = 60; depth=60; resolution=10

   implies that the cube being described is 60 cm by 60 cm by 200 cm,
   and is described to a resolution of 10 Angstroms.  The resolution
   gives the quantization unit, and therefore determines the quality of
   the reproduction.  The data stream itself then consists of a readout
   of the molecule found at each location, using the given resolution.
   If the resolution is high enough that more than one molecule is found
   in a given location, the molecule whose nucleus is closest to the
   center of the cube is used.  Each molecule is described by its
   molecular formula, rendered in ASCII for maximum readability if
   matter-transport mail is inadvertently delivered to a human recipient
   and displayed on a terminal screen.  Each molecule is followed by a
   space (ASCII 32) to separate it from the subsequent molecule
   description.  Extremely long molecules may require the use of a
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