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It's MIME, all MIME

The phone rings. Joe, your colleague in Oregon, is on his way out the door for a badly needed vacation. He's finally finished the draft of that manuscript, and has just e-mailed you a copy.

"Thank goodness," you think. "I've got to get it printed out by 4:30 p.m. today." You log into your VAX account, enter MAIL, and list your new mail messages. You breathe a sigh of relief - there it is, entitled Manuscript Draft. You page through its lengthy message header, and, then, see something like this:

----NextPart_000_01BACC.1A2AE0
Content_Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit

Here's the manuscript....I'll be unavailable until April 20.

Joe

----=_NextPart_000_01BAFECC.1A249AE0
Content-Type: application/octet-stream; name="draft.doc"
Content-Transfer-Encoding: base64
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"Aaarrggh! Joe has been working too hard: he sent the document in Martian! And he's gone for the next three weeks!!!" Relax. Believe it or not, the manuscript is really in there; it's just been sent as a MIME message.

A Few Words About MIME
Before giving the secret for decoding the draft document, let's talk about MIME for a minute. First, what is MIME? MIME is an abbreviation for Multipurpose Internet Mail Extensions. It's a standard for sending non-text information, such as images, audio, and word-processing documents, using electronic mail. It also allows multiple items, even if they are in different formats, to be included in a single mail message.

MIME's modus operandi is the addition of some special directions to the message that can be interpreted by many mail packages.

The Content-Type fields describe the type of information that's included. For example, the first part of Joe's message (the text that you could read) is plain text . The second part, which looks like gibberish, is binary data specific to an unknown application. PC users may recognize "doc" as the default extension for Microsoft Word. Other information, such as Content-Transfer-Encoding, describes the way non-text information has been encoded so that it can be sent via e-mail.

The upshot is that Joe has used a MIME-capable mail package to send you a Word document attached to his mail message. Your task is to convert the document back into its original Word format and transfer it into your favorite word processor. No problem, right?

Well, there's just one slight problem. VMS MAIL (what you use when you type mail at the $ prompt) isn't able to decipher MIME messages. Fortunately, there are two mail packages on Gemini that are MIME-savvy: PMDF MAIL and PMDF PINE. PMDF MAIL is very similar in usage to VMS MAIL; PMDF PINE uses a very different, menu-based interface (which many find more user-friendly).

Converting the encoded portion of the message back to a Word document is easier than you might expect. I don't have room to cover the procedure in all its variations with both packages, but here's an example, using PMDF MAIL. After typing pmdf mail at the $ prompt, and locating the message as you would with VMS MAIL, you page through the message until you come to something like the following:

%EMAIL-W-UNKAPLTYPE, unknown application subtype octet-stream 
Extract to a file with the EXTRACT command 
EMAIL>

Following the instructions, you would type extract draft.doc at the EMAIL> prompt. Presto, chango, you're done.

Well, almost done. If the original format of the item you extracted had been text (yes, people actually encode text files, usually inadvertantly), you would be done. However, in this case, you've got a Word document to read. Since programs such as Word and WordPerfect are not available on the VAX, you'll need to use a communications package (such as Kermit or WinQVT) to "download" draft.doc to your microcomputer for importation into a word processor. Instructions on transferring files are available in CH313.

Is This a One-Way Street?
Once you've made some changes to Joe's draft, you may be wondering if there is some way to make use of a MIME-capable mail program to get the Word document back to him. The answer is yes. Instructions on how to do so (as well as more information on using PMDF MAIL and PINE to manipulate MIME messages you receive) are available in the Computing Section of the TTU home page on the World-Wide Web.

Remember one thing Joe forgot: always check with an intended recipient before you send them a MIME message that contains encoded information. You need to make sure they have a mail program that can understand it!

This page maintained by: Lauren Neal
For additional information, contact Lauren Neal, LNeal@tntech.edu
Last updated: September 10, 2001