MPACK

Mpack is a program designed to pack and unpack files into MIME (Multipurpose Internet Mail Extensions) standard electronic mail messages.  Using MIME, you can send images, audio, motion pictures and other data between different computers via email.  In order to facilitate use of MIME, this program is available for DOS, Macintosh, Amiga and UNIX computers.  You may get the latest version of this program via anonymous ftp to ftp.andrew.cmu.edu in the /pub/mpack directory.  For more information send email to jgm+@cmu.edu or chrisn+@cmu.edu.  If you make interesting modifications to Mpack, please contact chrisn+@cmu.edu.

Encoding Files

To encode a file, select the “Encode File…” item in the File menu, or press âŒ˜E.  This will first bring up an open dialog to allow you to select the file you want to encode.  When you have finished selecting a file, it will bring up a dialog asking for the “MIME part prefix” to save the file as.  If the output email message is to be saved in a single text file, the filename you select here will be used.  If the output must be broken into several email messages, they will be named <name>.01, <name>.02, … where <name> is the “MIME part prefix” you select.  You may also enter a subject for your email (if you enter nothing, the name of the original file is used).  You may choose to split the encoded file into parts.  This is useful if you are sending the message through an obsolete email transport system.  If you do choose to split the file, the “Maximum Part Size” reflects the maximum number of characters Mpack will put in a single file.  Finally, if you check the “Add description file” box, you will be prompted for a text file to include describing the file you’re sending.

Decoding Files

To decode a set of MIME, uuencoded, or binhex encoded electronic mail files, select the “Decode Mail Files…” item in the File menu, or press âŒ˜D.  You will be presented with a standard open dialog to select the first file you wish to decode.  Once you’ve made your selection you will be presented with a list of all files that have the same prefix (followed by a number) as the file you selected.  You may add or remove files at will (with the “Add Files…” and “Remove” buttons), or start the decode process by pressing the “Decode” button.  Mpack will process the files and save the output in the appropriate file names.  If you receive only part of the files you wish to decode, Mpack will store temporary files in a “mpack-tmp” folder on the default volume until the rest of the files you wish to decode have been received.

Viewing Text Files

As an added convenience, Mpack allows you to view text files including the email files it creates, as long as those files aren’t too long.

Preferences

The first preference is the internet hostname.  This is the hostname used to generate message IDs when encoding files.  Some internet services will remove messages which don’t have a valid internet host in the message ID.  You should set this to the internet hostname of the machine from which you send email.

The second preference is the encoding method to use when encoding a file.  There are three ways to encode a Macintosh file in MIME.  The simplist way is to encode just the data fork of the Macintosh file using an appropriate MIME type.  When this is done the file’s type and creator (represented by it’s icon) and the resource fork is lost.  Macintosh applications may not be sent using this method.  The “applesingle” method converts the Macintosh file into a single encoded form that can only be read on another Macintosh.  Use of Applesingle is discouraged, except when the file contains no information that may be of interest to non-Macintosh users.  The “appledouble” method converts the Macintosh file into two parts: a Macintosh specific part and a data part usable by other machines.  The “auto” option will use the “data fork only” encoding for common MIME types (such as GIF and JPEG) or the “appledouble” encoding.  Regardless of the setting, a file with no data fork will be encoded using “applesingle’ encoding.

The third preference specifies whether or not Mpack will extract un-named text segments from the messages.

Setting Type/Creator options for MIME output

Mpack recognizes “text/plain”, “image/gif” and “image/jpeg” files automatically and stores them with useful type and creator fields.  If you wish to add support for more, or change the creators that Mpack uses, open the Mpack application using ResEdit, and add or modify the “TyCr” (Type/Creator) resources that Mpack uses.  The resource name of the “TyCr” resource should reflect the MIME type that it represents.

Distribution and Copyright

Copyright © 1993-1994 By John Myers and Chris Newman
All Rights Reserved.

Permission to use, copy, modify, and distribute this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the names of John Myers and Chris Newman not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.  John Myers and Chris Newman make no representations about the suitability of this software for any purpose.  It is provided "as is" without express or implied warranty.

JOHN MYERS AND CHRIS NEWMAN DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL JOHN MYERS OR CHRIS NEWMAN BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Portions of this code have the following copyright:

Copyright © 1991 Bell Communications Research, Inc. (Bellcore)

Permission to use, copy, modify, and distribute this material for any purpose and without fee is hereby granted, provided that the above copyright notice and this permission notice 
appear in all copies, and that the name of Bellcore not be used in advertising or publicity pertaining to this material without the specific, prior written permission of an authorized representative of Bellcore.  BELLCORE MAKES NO REPRESENTATIONS ABOUT THE ACCURACY OR SUITABILITY OF THIS MATERIAL FOR ANY PURPOSE.  IT IS PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES.

Portions of this code have the following copyright:

Copyright © 1991-2, RSA Data Security, Inc. Created 1991. All rights reserved.

License to copy and use this software is granted provided that it is identified as the "RSA Data Security, Inc. MD5 Message-Digest Algorithm" in all material mentioning or referencing this software or this function.

License is also granted to make and use derivative works provided that such works are identified as "derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm" in all material mentioning or referencing the derived work.

RSA Data Security, Inc. makes no representations concerning either the merchantability of this software or the suitability of this software for any particular purpose. It is provided "as is" without express or implied warranty of any kind.

These notices must be retained in any copies of any part of this documentation and/or software.