GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc910

Network Working Group Harry Forsdick Request for Comments: 910 BBN Laboratories

                                                           August 1984
                   Multimedia Mail Meeting Notes

Status of this Memo

 This memo is a report on a meeting about the experimental multimedia
 mail system (and in a sense a status report on that experiment).
 Distribution of this memo is unlimited.

1. Introduction

 A meeting was held at Bolt Beranek and Newman on 23-24 July 1984 to
 discuss recent progress by groups who are building multimedia mail
 systems and to discuss a variety of issues related to the further
 development of multimedia systems.  Representatives were present from
 BBN, ISI, SRI and Linkabit.  The list of attendees appears at the end
 of this note.
 The result of this meeting is a series of agreements that will be
 incorporated in the next set of experiments with multimedia mail as
 well as a set of items for further action.
 Note: There are references in this document to notes in a series
 devoted to multimedia mail.  These notes are available on-line in the
 directory [USC-ISIF]<MMM> and have the names MMM-N.TXT where N is the
 note number.  The file MMM-INDEX.TXT is a list of all of the notes in
 the series.  These public files may be copied via FTP using the FTP
 username ANONYMOUS and password GUEST.

2. Review of Status

 Status reports on work accomplished in the last year were given by
 each organization.

2.1. BBN

 The initial implementation of Diamond is complete and runs on the
 Jericho workstation.  Diamond currently supports the exchange of
 compound documents which contain text, graphics, images, voice and
 spreadsheet/charts.  A demonstration of this system was presented
 showing both the user's view of Diamond messages and message
 management as well as the interactions between the components of this
 distributed system. Diamond currently uses the TOPS-20 implementation
 of MPM for inter-cluster message transport but the plan is to
 integrate an implementation of MPM for the Sun Workstation into
 Diamond.  Current activity is focused on porting Diamond to the Sun
 Workstation.  A first version of Diamond for the Sun is nearly

Forsdick [Page 1]

RFC 910 August 1984 Multimedia Mail Meeting Notes

 completed and parts (the document editor) were demonstrated running
 on the Sun.  Diamond will be used in the ADDCOMPE testbed with
 100-200 users expected in the next year or so.  Future plans include
 building on the experience gained with Diamond in the area of
 multimedia conferencing, extending the use of multimedia into other
 application areas and applying the distributed architecture of
 Diamond to other application areas.

2.2. ISI

 A new effort aimed at developing a user interface on a Xerox 1108
 (Dandelion) workstation has just begun.  All of the implementation is
 being done in Interlisp.  Initial work has been done to implement IP
 and TFTP on the 1108 as well as a document editor that makes use of
 the Interlisp-D window system.  Work on the user interface that was
 developed on the Perq will be cycling down.  The implementation of
 the MPM on TOPS-20 is essentially complete with the addition of MPM
 to SMTP mail conversion; no major changes are anticipated.  The
 TOPS-20 MPM will be used as the message transport facility for the
 1108 user interface implementation.  TFTP will be used to get
 messages from the 1108 to the TOPS-20.

2.3. SRI

 The SRI multimedia mail system consists of three parts: The
 Multimedia Mail Handler (MMH) which is the user's interface for
 managing mail, the Structure Editor (SE) which is used to view and
 compose multimedia messages and the MPM for mail transport.  This
 system is implemented on the Sun Workstation.  The first release of
 the MPM on the Sun will be ready for distribution at the end of this
 summer.  The SE is used to view and compose structures of multimedia
 objects.  Currently there is support for text, voice and graphics.
 Another effort at SRI involves integration of applications to run in
 the ADDCOMPE testbed.  Diamond will be the first example of an
 application which uses multimedia data in the testbed.  SRI is
 interested in examining the issues associated with multimedia systems
 to determine how multimedia data can be used in other applications
 that might be put into the testbed.

2.4. Linkabit

 Linkabit has recently received a contract to work on protocol
 evaluation, problems associated with working in a large internet
 environment, and new real-time end-to-end services.  They will be
 working with Sun workstations.  Areas of interest are protocols,
 multimedia conferencing and domains.

Forsdick [Page 2]

RFC 910 August 1984 Multimedia Mail Meeting Notes

3. Discussions and Agreements

3.1. Conversion to the New Multimedia Syntax

 There was general agreement that in future experiments we would all
 adopt the revised syntax for multimedia mail as described in the
 Final Report to SRI Project 5363.  It was agreed that RFC767 should
 be revised to reflect these changes.  The timing for switching over
 should be as soon as possible and should be completed by October 1,
 1984.

3.2. Graphics Representation

 A wide ranging discussion on the way in which graphics is to be
 represented in multimedia documents occurred.  It was generally
 agreed that the first style of graphical object to be included in
 multimedia messages would be a simple line-drawing, such as those
 that can be produced by the many "draw" programs (e.g. LisaDraw)
 currently in existence.  Attention was focused on the two existing
 standards (ACM-CORE and GKS) and the interim protocol used in the
 Diamond system.  Two major problems with the existing standards were
 mentioned:
    o In both ACM-CORE and GKS grouping is inadequate or non-existent.
      This means that it is difficult or impossible to build up a
      composition of several graphical objects and then manipulate
      that composite as a single graphical object.
    o Neither ACM-CORE or GKS have specified a standard method for
      representing graphical drawings in memory (e.g. long term file
      storage).  This is one of the most important aspects of a
      graphical standard for multimedia mail.  The focus of graphical
      standards so far has been towards driving devices in a
      independent manner, not storing graphics in a standard
      representation.
 A presentation of the representation for graphical objects in Diamond
 was given.  The protocol is documented in MMM-18 and MMM-23.
 Requests for hardcopies of the diagrams in those documents (sigh) can
 be sent to Travers@BBN.
 The discussion then focused on the level of effort required to switch
 from one representation to another.  It was generally agreed that
 compared to the entire editor used to manipulate graphical objects
 (e.g., the "draw" program), the part that reads or writes objects
 from or to files is relatively simple.  Most draw programs have a
 unique internal representation which is built when reading the file
 representation and used as the source when writing the file

Forsdick [Page 3]

RFC 910 August 1984 Multimedia Mail Meeting Notes

 representation.  It is this relatively small portion of a graphics
 editor which is impacted by switching from one file representation to
 another.  Thus it seemed that the approach of adopting one interim
 representation now and planning to switch to a standard
 representation when work on the standards solve the problems noted
 above was reasonable.
 After considerable examination of the issues, the following decisions
 were reached:
    1. The representation for graphics used in Diamond and documented
       in MMM-18 and MMM-23 will be adopted as an interim
       representation for graphics in multimedia mail.  It will be
       known as the MMGraphics1 protocol.
    2. We will actively track development of the GKS standard and also
       examine a GKS-subset that has been developed by Sandia Labs.
    3. We agreed to settle on an adopted international standard
       eventually.

3.3. Document Presentation Semantics

 There was a presentation of the ideas contained in MMM-22: "A Format
 for the Construction of Multimedia Messages".  The resulting
 discussion addressed the following issues:
    o Presentation of documents on display devices with different
      characteristics (dimensions, resolutions, available fonts,
      etc.).
       The essence of the conversation was that there is no single set
       of fonts, or page sizes that will cover all of the
       possibilities. There was a strong feeling that as long as the
       display surface was of reasonable size that a document should
       be presented in a "correctly" formatted manner.  Rather than
       the originator of a document specifying hard page boundaries,
       the intent of the originator regarding formatting and grouping
       of objects in the document should be preserved and used when
       the document is actually presented on a display device.  A
       window on a bitmap display and a hardcopy page printer are both
       examples of display devices.
    o The desire to represent the kinds of documents that currently
      exist in the world of hardcopy as well as to represent documents
      that can take advantage of the new possibilities of electronic
      creation, storage and presentation.

Forsdick [Page 4]

RFC 910 August 1984 Multimedia Mail Meeting Notes

 Several points were made:
    1. One of the first goals for multimedia systems should be to
       represent the types of documents that are prevalent in the
       hardcopy world.  People are already familiar with these
       documents and will expect multimedia systems to, at least, be
       able to deal with them.
    2. In an effort to provide the capabilities of electronically
       originated documents based on the hardcopy model of documents,
       we should not eliminate the great potential of electronic
       documents that have much greater reactive qualities.  For
       example, a document where a graphical figure and a textual
       explanation of that figure are linked so that as long as the
       explanation is being read the figure is visible.
    3. In many situations being able to carry away a paper copy of a
       document is a requirement even if the document was not
       primarily intended to be presented in hardcopy.
 The following agreements were made:
    1. A method for recording the author's intent regarding the
       presentation of a document should be developed.  This
       representation would defer decisions on final presentation
       bindings of size, resolution and fonts to the reader's document
       presenter.
       Topics addressed by this representation will include:
          o Grouping of objects
          o Limited Font attributes (e.g., normal, bold, italic)
          o Headings, Footings
          o Sectioning
       Of course the reader's document presenter is free to ignore any
       of the author's intentions it cannot deal with.  The point of
       this representation is to record the author's desires but to
       defer final decisions on how to use the intentions until the
       capabilities of the reader are known.
       This representation will lie some where between the rather
       loose spatial and temporal positioning commands currently in
       the protocol (Sequential, Simultaneous and Independent) and the

Forsdick [Page 5]

RFC 910 August 1984 Multimedia Mail Meeting Notes

       absolute positioning of a system that defines rigid page
       boundaries and absolute positions for object placement on a
       page.
    2. We will NOT try to make this representation handle all of the
       issues addressed by modern document formatting systems.
       Instead we will skim off some of the most useful ideas but
       perhaps limit the flexibility present in these complex
       formatting systems.
    3. The document representation will be able to describe
       relationships between objects that make use of the capabilities
       of electronic document presentation, such as simultaneous
       presentation (i.e., two objects which are visible at the same
       time) and overlay presentation (i.e., two (possibly
       transparent) objects which occupy the same area in a document,
       which may also be separated under viewer control).
    4. Methods should be developed for all aspects of the document
       representation for presenting the document in a hardcopy form.
       This applies both electronic documents that fit the tradition
       hardcopy model as well as those that make use of the more
       reactive features of the representation.

3.4. Directory Service

 There is an increasing need to be able to determine attributes of
 users, hosts and domains throughout the DARPA Internet.  For example,
 when composing the header fields of a message it is useful to be able
 to inquire about the mail box location of a person to whom the
 message is addressed. Likewise, there is need to determine the
 services provided by a host so that requests that will never be
 satisfied can be avoided.
 The feeling of the group was that work on the Internet Domain system
 (being done at ISI and Berkeley) would answer some of these problems
 and that we should examine the design documents to see how that
 system might help us (see RFCs 882 and 883).  The WhoIs server is
 useful, but only for information about the text mail box of a person
 (see RFC812).

Forsdick [Page 6]

RFC 910 August 1984 Multimedia Mail Meeting Notes

3.5. New Media Types

 The discussion dealt with three topics:  A proposal for a new media
 type, ideas for other new media types and provisions for dealing with
 unknown media types.
 A description of the Diamond SpreadSheet/Chart media type was
 presented.  This is documented in MMM-24.  In this media it is
 possible to represent a table containing numbers, labels, dates and
 formulas.  A unique attribute of this media type is that the
 spreadsheet model as well as the data are transmitted.  The reader of
 a document containing a spreadsheet object can test what effect
 different data would have on conclusions suggested by the spreadsheet
 object.  A spreadsheet may appear as a table and/or one of several
 alternative business charts (line graph, scatter graph, bar chart or
 pie chart).  Rulings may be added to the tabular representation so
 that it is possible to achieve the appearance of sophisticated
 tabular data presentation.  During the discussion, the point was made
 that a minimal implementation of the spreadsheet object could ignore
 the formulas and just present the values of the cells, thus allowing
 a minimal presentation of the tabular and chart information.
 Ideas for new media types included:
    Form
       A set of fields which are Name-Value pairs.  Forms can be used
       for presentation and/or acceptance of information. The act of
       filling out a form might be used (under user approval) to
       trigger sending the completed form to the appropriate person
       who handles such forms.
    Animated Graphics
       A line drawing that has temporal information encoded in the
       presentation of its components.  The idea is that parts of a
       graphics object could move about the object during its
       presentation.  For example, an arrow could move about a map
       showing a route to be followed.  There was some discussion
       about how this would interact with other media.  For example,
       how could an arrow moving about a map be coordinated with voice
       instructions on how to get from one place to another.  There
       were no decisions about how best to accomplish this.
 Finally, we agreed that all of our systems should be prepared to
 accept (and possibly ignore) media types that are not currently
 implemented.  The common way of dealing with this is to include a
 statement of the form "An object of type <Type> appears here".  With

Forsdick [Page 7]

RFC 910 August 1984 Multimedia Mail Meeting Notes

 the regularized syntax that has been adopted many of the common
 attributes of all object types will be able to be understood but the
 actual type may not be implemented.  In Diamond we would like to use
 the MPM to transfer Diamond messages between Diamond and non-Diamond
 clusters.  Currently if we were to include a spreadsheet in one of
 these messages, all of the other implementations of multimedia mail
 would probably end in the debugger when they went to process our
 messages, rather than indicate that there was something that they
 didn't quite understand.

3.6. MPM Support

 By the end of the summer there will be two implementation of the MPM:
 on TOPS-20 and on the Sun Workstation.  We agreed to try to set up
 the following operational MPMs:
    Organization  Host          MPM Implementation
    ISI           ISIF          TOPS-20
    ISI           ISIB          TOPS-20
    SRI           ?             Sun Workstation
    BBN           ?             Sun Workstation
    DARPA         ?             Sun Workstation
    Linkabit      DCN6          Sun Workstation
 The idea behind this agreement is to get wide geographic coverage to
 allow us to use multimedia mail on a regular basis and to test the
 impact of realistic use of multiple communicating MPMs using the
 Internet.

3.7. Floating Point Data Type

 In the representation for data defined in RFC759, there is no way to
 represent floating point numbers.  We agreed that a new data type
 should be added, called Float64 which is the 64-bit IEEE standard
 floating point number representation.

3.8. Captions

 The idea of including a text caption as an optional property of every
 object was discussed.  There are several uses of such a caption:
    o For media like voice which do not have an implicit visual
      representation, it is useful to include a caption indicating
      something about the object.  This caption can serve as a visual
      indication of the presence of the non-visual object.

Forsdick [Page 8]

RFC 910 August 1984 Multimedia Mail Meeting Notes

    o When an implementation of a multimedia message system doesn't
      support a given media type, it can be useful to give some
      information about the object in the form of a text passage.
    o In some situations, it is important to present an outline of a
      document.  Captions associated with each object could be used to
      generate a shortened abstract of the document.
 We agreed to add to all object types an optional property whose name
 is "Caption" and whose value is of type Text String.

3.9. More Users of Multimedia Mail

 We need to increase the use of multimedia mail to gain more
 experience with issues that need attention.  This can be done by:
    o Encouraging more sites to participate in the experiments.  There
      are several possible sites which have Sun workstations that
      could be configured to run an MPM and one of the multimedia
      message systems.
    o Making the MPMs perform translations to and from SMTP text-only
      mail.  At BBN, the Diamond Import/Export component performs
      translations in both directions and this has proved very useful
      in testing the operation of our system.  In addition, the
      inclusion of statements such as <Graphics appears here> might
      spark interest from text-only mail recipients, although care
      should be taken not to offend anybody with this kind of "class
      differentiation".
 To the extent possible, the Sun Workstation MPM will be modified to
 perform translations to and from SMTP mail.  The TOPS-20 MPM already
 does the translation from multimedia mail to text-only mail.  It may
 be possible to add translation in the other direction.

3.10. Multimedia Exploder Mailing List

 A mailing list devoted to Multimedia Mail will be set up at ISI.
 This will be of the "exploding" variety so that sending a message to
 the list will cause everybody on the list to receive a copy.  To get
 on or off the list send a note to MMM-People-Request@USC-ISIF.ARPA.
 The exploder mailbox is MMM-People@USC-ISIF.ARPA.

Forsdick [Page 9]

RFC 910 August 1984 Multimedia Mail Meeting Notes

3.11. Next Experiment

 The next experiment will be in January 1985.  At that time we will
 try to demonstrate the following new features:
    o Use of the revised multimedia syntax described in section 3.1.
    o Inclusion of Graphics objects, in addition to Text, Images and
      Voice.
    o Use of the, as yet unspecified, document presentation semantics
      described in section 3.3.
    o Use of the Sun Workstation MPMs.

4. Further Actions

 Several of the agreements reached require further action.  I have
 added dates which seem reasonable.
    Revision of RFC759 to include Float64 data type.
    Person:  Greg Finn and Jon Postel.
    Due Date: 1 September 84.
    Conversion to the new Multimedia Syntax
    Person:  All groups.
    Due Date: 1 September 84.
    Revision of RFC767 to reflect revised Multimedia Syntax and
    optional Caption property
    Person:  Jose Garcia-Luna and Jon Postel
    Due Date: 1 October 84.
    Specification of Document Presentation Semantics (Section 3.3)
    Person:  Harry Forsdick
    Due Date: 1 October 84.
    Acquisition of GKS and GKS-subset documentation
    Person:  Lou Schreier
    Due Date: 1 September 84
    Completion of initial implementation of Sun Workstation MPM
    Person:  Andy Poggio
    Due Date: 15 September 84
    Multimedia Exploder Mailing List
    Person:  Greg Finn
    Due Date: 15 August 84       < COMPLETED >

Forsdick [Page 10]

RFC 910 August 1984 Multimedia Mail Meeting Notes

    Addition of MPM<==>SMTP translation logic to Sun Workstation MPM
    Person:  Mike O'Connor
    Due Date: 1 November 84
    Demonstrate Text-Graphics-Image-Voice Document Exchange
    Person:  All
    Due Date: January 85

5. Attendees

 Harry Forsdick     BBN       Forsdick@BBN       (617) 497-3638
 David L. Mills     Linkabit  Mills@ISID         (703) 734-9000
 Louis Schreier     SRI       Schreier@SRI-SPAM  (415) 326-6200
 Philip Au          SRI       Psa@SRI-SPAM       (415) 326-6200
 Greg Finn          ISI       Finn@ISIF          (213) 822-1511
 Mike O'Connor      Linkabit  OConnor@DCN9       (703) 734-9000
 Ray Tomlinson      BBN       Tomlinson@BBN      (617) 497-3363
 Ginny Travers      BBN       Travers@BBN        (617) 497-2647
 Terry Crowley      BBN       TCrowley@BBN       (617) 497-2677
 Andy Poggio        SRI       Poggio@SRI-TSC     (415) 859-5094
 Jose Garcia-Luna   SRI       Garcia@SRI-TSC     (415) 859-5647
 George Robertson   BBN       GRobertson@BBN     (617) 497-3632

Forsdick [Page 11]

/data/webs/external/dokuwiki/data/pages/rfc/rfc910.txt · Last modified: 1992/09/22 20:58 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki