MIME Encapsulation of Macintosh Files - MacMIME
RFC 1740

Document Type RFC - Proposed Standard (December 1994; No errata)
Was draft-faltstrom-macmime1 (individual)
Last updated 2013-03-02
Stream Legacy
Formats plain text html pdf htmlized bibtex
Stream Legacy state (None)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state RFC 1740 (Proposed Standard)
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                   Patrik Faltstrom
Request for Comments: 1740                 Royal Institute of Technology
Category: Standards Track                                   Dave Crocker
                                                  Brandenburg Consulting
                                                            Erik E. Fair
                                                     Apple Computer Inc.
                                                           December 1994

            MIME Encapsulation of Macintosh files - MacMIME

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

   This memo describes the format to use when sending Apple Macintosh
   files via MIME [BORE93].  The format is compatible with existing
   mechanisms for distributing Macintosh files, while allowing non-
   Macintosh systems access to data in standardized formats.

2.  Introduction

   Files on the Macintosh consists of two parts, called forks:

   Data fork:       The actual data included in the file.  The Data
                    fork is typically the only meaningful part of a
                    Macintosh file on a non-Macintosh computer system.
                    For example, if a Macintosh user wants to send a
                    file of data to a user on an IBM-PC, she would only
                    send the Data fork.

   Resource fork:   Contains a collection of arbitrary attribute/value
                    pairs, including program segments, icon bitmaps,
                    and parametric values.

   Additional information regarding Macintosh files is stored by the
   Finder in a hidden file, called the "Desktop Database".

   Because of the complications in storing different parts of a
   Macintosh file in a non-Macintosh filesystem that only handles
   consecutive data in one part, it is common to convert the Macintosh
   file into some other format before transferring it over the network.

Faltstrom, Crocker & Fair                                       [Page 1]
RFC 1740                  MIME-based Mac files             December 1994

   The two styles of use are [APPL90]:

   AppleSingle:   Apple's standard format for encoding Macintosh files
                  as one byte stream.
   AppleDouble:   Similar to AppleSingle except that the Data fork is
                  separated from the Macintosh-specific parts by the
                  AppleDouble encoding.

   AppleDouble is the preferred format for a Macintosh file that is to
   be included in an Internet mail message, because it provides
   recipients with Macintosh computers the entire document, including
   Icons and other Macintosh specific information, while other users
   easily can extract the Data fork (the actual data) as it is separated
   from the AppleDouble encoding.

2.  MIME format for Apple/Macintosh-specific file information

   2a.  APPLICATION/APPLEFILE

      MIME type-name:            APPLICATION
      MIME subtype name:         APPLEFILE
      Required parameters:       none
      Optional parameters:       NAME, which must be a "value" as
                                 defined in RFC-1521 [BORE93].
      Encoding considerations:   The presence of binary data will
                                 typically require use of
                                 Content-Transfer-Encoding: BASE64
      Security considerations:   See separate section in the document
      Published specification:   Apple-single & Apple-double [APPL90]
      Rationale:                 Permits MIME-based transmission of
                                 data with Apple/Macintosh specific
                                 information, while allowing general
                                 access to non-specific user data.

   2b.  MULTIPART/APPLEDOUBLE

      MIME type-name:            MULTIPART
      MIME subtype name:         APPLEDOUBLE
      Required parameters:       none
      Optional parameters:       NAME, which must be a "value" as
                                 defined in RFC-1521 [BORE93].
      Encoding considerations:   none
      Security considerations:   See separate section in the document
      Published specification:   Apple-single & Apple-double [APPL90]
      Rationale:                 Permits MIME-based transmission of
                                 data with Apple/Macintosh specific
                                 information, while allowing general
                                 access to non-specific user data.

Faltstrom, Crocker & Fair                                       [Page 2]
RFC 1740                  MIME-based Mac files             December 1994

   2c.  Detail specific to MIME-based usage
Show full document text