MIME Encapsulation of Macintosh Files - MacMIME (RFC1740)

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

P. Faltstrom: AUTHOR [+2][-]

D. Crocker: AUTHOR

E. Fair: AUTHOR

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.

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.

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 ma...