Network Working Group                                        E. Levinson
Request for Comments: 1895                     Accurate Info. Sys., Inc.
Category: Informational                                    February 1996


                The Application/CALS-1840 Content-type

Status of this Memo

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

Abstract

  This memorandum provides guidelines for using the United States
  Department of Defense Military Standard MIL-STD-1840, "Automated
  Interchange of Technical Information," with the Internet electronic
  mail standards, RFC 822 and RFC 1521.  Electronic mail provides a
  more convenient mechanism that delivery via physical media for
  certain types and quantities of data.  Software already exists to
  support data exchanges based on MIL-STD-1840 and it can continue to
  be used in conjunction with electronic mail exchanges defined in this
  document.  This document defines a new media type and a MIME message
  structure for exchanging data in conformance with MIL-STD-1840.

1.  Introduction

  The United States Department of Defense (DOD) has defined a standard,
  MIL-STD-1840 [1840], for the exchange of digital data.  Most
  applications of that standard use 9-track tape as the transport
  medium.  The Application/CALS-1840 media-type is proposed to
  facilitate such exchanges using the Multipurpose Internet Mail
  Extensions [MIME] and network based transport media, i.e. electronic
  mail [822].

  This memo has been reviewed and authorized by the Continuous
  Acquistion and Life-cycle Support (CALS) Industry Steering Group
  (ISG).  CALS is a US DOD initiative for the use and exchange of
  digital data.  The Industry Steering Group, which consists of members
  drawn from government and industry, guides the development of CALS
  standards such as [1840].

2.  Definition

  An [1840] exchange consists of a set of files with well defined file
  names (see below).  Each set consists of a declaration file and one
  or more data files.  The data files, in turn, consist of header



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  records immediately followed by the data.  The data itself may be
  formatted in accordance with a published specification or a
  contractual agreement.

  MIL-STD-1840 encodes the file's data type in the file name.

  It might seem appropriate to transform the 1840 headers into MIME
  headers and use the appropriate media type, essentially transforming
  the 1840 files into MIME body parts.  There are three reasons for not
  doing that.  First, not all of the "types" used in [1840] are
  registered MIME types.  Second, there exists an installed base of
  software capable of reading the 1840 formatted files and processing
  the data appropriately.  Finally the three existing revisions to the
  standard have maintained the same file structure.  Consequently, a
  processor for the data may be able to handle any one of the
  standard's revisions.  Thus, a single Application/CALS-1840 is being
  proposed and its body part body contains headers and data in the
  [1840] format.

  A set of related files constitutes a "transfer unit" in 1840 and each
  transfer unit shall correspond to a Multipart/Mixed MIME entity.
  Included in each transfer unit is a declaration file which shall be
  the first body part in the Multipart/Mixed entity.  Several transfer
  units may be included in a single MIME message.



























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2.1  Registration Information

  The following form is copied from RFC 1590, Appendix A for the
  purpose of registering this media-type.

  To:  [email protected]
  Subject:  Registration of new Media Type content-type/subtype

  Media Type name:           Application
  Media subtype name:        CALS-1840
  Required parameters:       filename, version
  Optional parameters:       None
  Encoding considerations:   Any valid MIME encodings my be used
  Security considerations:   Depends solely on the referenced type
  Published specification:   This document
  Person & email address
  to contact for further
  information:               Alan Peltzman <[email protected]>
                             +1 (703) 735-3568
                             Defense Information Systems Agency
                             Center for Standards
                             Code JIEO/JEBEB
                             10701 Parkridge Blvd
                             Reston, VA 22091-4398

2.2.  The Filename Parameter

  The filename parameter gives the transfer unit filename as defined by
  [1840].  The parameter's value, called <1840-name>, has the syntax
  given by the grammer below.

       1840-name  := "D" 1840-tuseq [ 1840-type 1840-dfseq ]
       1840-type  := letter ; limited to the set defined in
                            ; the appropriate version of
                            ; [1840, Table III]
       1840-tuseq := 1840-seq
       1840-dfseq := 1840-seq
       1840-seq   := alphnum alphnum alphnum
       alphanum   := letter / digit
       letter     := "A" / "B" / "C" / "D" / "E" / "F" / "G" /
                     "H" / "I" / "J" / "K" / "L" / "M" / "N" /
                     "O" / "P" / "Q" / "R" / "S" / "T" / "U" /
                     "V" / "W" / "X" / "Y" / "Z"
       digit      := "0" / "1" / "2" / "3" / "4" / "5" /
                     "6" / "7" / "8" / "9" /






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  All Application/CALS-1840 body parts in a single Multipart/Mixed MIME
  entity shall have the same <1840-tuseq>.  Within a single message all
  filename values shall be unique.

  Notes: 1) Tuseq and dfseq correspond to transfer unit sequence number
  and data file sequence number respectively.  2) The filename for a
  declaration file has the form "D" 1840-tuseq and for data files, the
  form "D" 1840-tuseq <letter> 1840-dfseq.

2.3.  The Version Parameter

  The specversion parameter's value shall indicate the particular
  version of MIL-STD-1840 to which the data conforms.  Valid values
  are:

       MIL-STD-1840C, 0, 199XXXXX
       MIL-STD-1840B, 0, 19921103
       MIL-STD-1840A, 0, 19871222

  Notes: (1) The value "199XXXXX" is to be replaced with the actual
  issue date for MIL-STD-1840C. (2) The embedded blanks in the above
  strings are required, hence the value must be enclosed in quote marks
  (").

3. Example

  In the example below a single transfer unit is provided.  It consists
  of three data files, the declaration, a contract defined file and an
  IGES file.  The headers and data are in accordance with MIL-STD-
  1840B.  The content-transfer-encoding perserves the data file's fixed
  record length.

       To:   [email protected]
       From: [email protected]
       Date: Fri, 03 Nov 1995 18:23:10 -0500
       MIME-Version: 1.0
       Content-Type: Multipart/Mixed;
           Boundary="DISA CFS - SFC ASID"

       --DISA CFS - SFC ASID
       Content-Type: Application/CALS-1840; filename=D001;
           version="MIL-STD-1840B, 0, 19921103"
       Content-Transfer-Encoding: Base64

       [Declaration File]
       --DISA CFS - SFC ASID
       Content-Type: Application/CALS-1840; filename=D001A001;
           version="MIL-STD-1840B, 0, 19921103"



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       Content-Transfer-Encoding: Base64

       [Data File -- Contract Defined including headers]
       --DISA CFS - SFC ASID
       Content-Type: Application/CALS-1840; filename=D001Q001;
           version="MIL-STD-1840B, 0, 19921103"
       Content-Transfer-Encoding: Base64

       [Data File -- Raster including 1840 headers]
       --DISA CFS - SFC ASID--

4.  Security Considerations

  None of the body parts, as constitued, represent executable data.
  When the 1840 file format is processed the resultant data may be
  executable.  Processing will be under the control of the process
  associated with Application/CALS-1840.

  Classified information or other information that cannot be disclosed
  except to authorized personnel should not be sent via the Internet
  without using appropriate privacy enhancements, [PEM], [MOSS], or
  other privacy mechanism.

5.  Acknowledgments

  The author acknowledges the encouragement of Alan Peltzman, US DOD,
  DISA, and the suggestions of Richard Klobuchar, SAIC.

  This work was supported under U.S. Dept. of the Army, Contract
  DAAB07-93-D-T001 and prepared under the direction of the MIL-STD-1840
  Revision C Review Team.

6.  References

  [1840]      MIL-STD-1840B, "Automated Interchange of Technical
              Information", US Department of Defense, 3 November 1992.

  [822]       Crocker, D., "Standard for the Format of ARPA Internet
              Text Messages", STD 11, RFC 822, UDEL, August 1982.

  [MIME]      Borenstein, N. and N. Freed, "MIME (Multipurpose Internet
              Mail Extensions): Mechanisms for Specifying and
              Describing the Format of Internet Message Bodies", RFC
              1521, Bellcore and Innosoft, September 1993.

  [MOSS]      Crocker, S., Freed, N., Galvin, J., and S. Murphy, "MIME
              Object Security Services", RFC 1848, Cybercash, Innosoft,
              TIS, October 1995.



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  [PEM]       Linn, J., "Privacy Enhancement for Internet Electronic Mail:
              Part I: Message Encryption and Authentication Procedures",
              RFC 1421, IAB IRTF PSRG, IETF PEM WG, February 1993.

9.  Author's Address

  Edward Levinson
  Accurate Information Systems, Inc.
  2 Industrial Way
  Eatontown, NJ  07724-2265
  USA

  Phone: +1 908 389 5550
  EMail: [email protected]





































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