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rfc:rfc1437

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
 content-transfer-encoding such as quoted-printable, to ensure that
 line-wrapping mail systems do not, for example, cause the unintended
 breakdown of complex proteins into their constituent elements.

Borenstein & Linimon [Page 2] RFC 1437 MIME Content-Types for a New Medium 1 April 1993

 The following is a message that gives a somewhat simplified rendition
 of a well-known American politician, starting from the top:
 From:  "Nathaniel S. Borenstein" <nsb@bellcore.com>
 To: Mark Linimon <linimon@lonesome.com>
 Subject: Think hard before reconstructing
 Content-description:  Dan Quayle, low-res version
 Content-type: matter-transport/sentient-life-form
         height = 200; width = 60; depth=60; resolution=100000
 Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe  Fe
 Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe  Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 NO2 Fe
 Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe  Fe
 Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe  Fe
 Obviously, a real politician's skull is more complex than pure iron,
 as is its interior, but this simplified example should give the
 general flavor of the protocol.
 (A caveat, however, in the reconstitution of Vice-Presidents of the
 United States: allegedly, some of the matter-reconstitution schemes
 currently under development are reputed to perform less than
 optimally while trying to reconstitute areas of relatively high
 vacuum; for instance, their skulls.  A recommended acceptance test
 might be to experiment with subjects whose skulls are only at partial
 vacuum, such as Vice-Presidents of Marketing.)

MHS (X.400) Gateway Considerations

 The proper behavior of a MIME/MHS gateway with regard to the
 transmission of complex multimedia messages is a topic of ongoing
 investigation under the auspices of the IETF.  The addition of matter
 transport should not significantly complicate that effort, as it is
 already necessary to specify gateway behavior for MIME types that
 have no X.400 equivalents, and matter transport is simply another

Borenstein & Linimon [Page 3] RFC 1437 MIME Content-Types for a New Medium 1 April 1993

 such untranslatable type.
 However, real-world X.400 gateways might be considered to
 significantly increase the hazard that mail containing a human being
 will be rejected with a message so cryptic that the recipient deletes
 it without ever realizing that an embedded human being is enclosed.
 For this reason, it is recommended that the subject of matter
 transport be explicitly marked "for further study" in the next
 generation of the X.400 specification, X.400-1996.  This will give
 the community ample time to define a more complete specification for
 matter transport as part of X.400-2000, and possibly even a readily-
 implementable specification as part of X.400-2004, although some will
 no doubt argue that this would be too strong a break with tradition.

Implementation Considerations

 The user is cautioned against passing MIME transporter messages
 through computers equipped with the NFS file system.  A no-file space
 error caused one of the laboratory rats on our prototype system to be
 truncated to a zero-length file.  Unfortunately we had neglected to
 mount a scratch rat.  (We have decided to permanently retain the
 empty filename in his honor).
 Byte swapping problems on other storage systems can be similarly
 annoying, but should not be a problem if network byte order is always
 maintained ocrrcelty.
 Despite the authors' belief in the robustness of the protocol,
 passage of email through certain systems seems to result in the
 sentient-life-form arriving at its destination upside down, resulting
 in an annoying "thud".  The cause is still under investigation.
 Interoperation with matter-transporters using polar coordinate
 systems is discouraged, due to round-off and other algorithmic errors
 in certain ubiquitous floating-point implementations, leading to
 results which are best discreetly described as "disappointing."
 Similarly, off-by-one errors should be avoided.
 Widespread adoption of this protocol may lead to an increase in user
 demand for reliable backup systems.  More importantly, for the first
 time management may be motivated to adequately fund such systems when
 they discover the possibility that proper email backup may confer
 upon them virtual immortality.  (On the other hand, implementors
 should seriously consider the desirability of making their managers
 immortal.)

Borenstein & Linimon [Page 4] RFC 1437 MIME Content-Types for a New Medium 1 April 1993

 An additional concern reflects the fact that, prior to the
 introduction of this content-type, duplicate mail delivery was a
 relatively minor nuisance.  With the mail extensions described in
 this document, however, comes the possibility that duplicate mail
 delivery will leave a user with, for example, multiple spouses or
 mothers-in-law.  The relative weights of the desire to avoid
 duplicate delivery and the desire to avoid lost mail may change
 accordingly.

Security Considerations

 Security considerations are not discussed in this memo.  However, law
 enforcement officials might wish to consider the possibility that
 this mechanism could be used by criminals, either to escape
 extradition by mailing themselves outside of a legal jurisdiction, or
 to outwait the statute of limitations by mailing themselves through
 complex mail routes with long delays.  (One supposes that they could
 also look on the bright side, and consider MIME as a possible
 approach to solving the long-standing problem of prison
 overcrowding.)

Authors

 The authors of this document may be reconstituted by feeding the
 following data to an Internet-connected MIME reader:

Content-type: multipart/mixed; boundary=NextAuthor

–NextAuthor Content-type: message/external-body; access-type=anon-ftp;

      site=thumper.bellcore.com; directory=pub/nsb; name=nsb.flesh

Content-Description: Nathaniel Borenstein

Content-type: matter-transport/sentient-life-form

      height = 200; width = 60; depth=60; resolution=100000

–NextAuthor Content-type: message/external-body; access-type=anon-ftp;

      site=thumper.bellcore.com; directory=pub/nsb; name=linimon.flesh

Content-Description: Mark Linimon

Content-type: matter-transport/sentient-life-form

      height = 200; width = 60; depth=60; resolution=100000

–NextAuthor–

Borenstein & Linimon [Page 5] RFC 1437 MIME Content-Types for a New Medium 1 April 1993

Authors' Addresses

 Nathaniel Borenstein
 Bellcore Room MRE 2D-296
 445 South Street
 Morristown, NJ 07962-1910
 Phone: (201) 829-4270
 EMail: nsb@bellcore.com
 Mark Linimon
 Lonesome Dove Computing Services
 P.O. Box 20291
 Roanoke, VA 24018
 Phone: (703) 776-1004
 EMail: linimon@LONESOME.COM

Borenstein & Linimon [Page 6]

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