ME currently covers a wide range of formats, or Internet Media Types, including Microsoft Word, Unix tar, QuickTime, ZIP, PostScript, RealAudio, and Macintosh PICT.
Proprietary messaging systems can and do support MIME. However, the MIME attachments must go through a conversion process at a server gateway, and this is a controversial point between Internet and proprietary messaging advocates. "Gateways are designed to lose information," says Paul Hoffman, director of the Internet Mail Consortium. The proprietary side claims that gateways are relatively sound -- as long as they are "properly configured."
Barbarians at the Gate
When a MIME attachment hits a gateway, the gateway determines its type and automatically converts the document to the appropriate equivalent format. The conversion also
strips out data
deemed unnecessary. If the gateway makes a mistake, however, the recipient of that document has no way of recovering that message, other than to ask the sender to deliver it by some other means. Even if the attachment converts properly, it could lose its structure. For instance, you might send a snazzy-looking Word document with handsome fonts and a carefully planned format as an attachment, only to have the recipient see it as a block of regular text. "Structure is information, too," says Hoffman.
Hoffman admits that a well-designed gateway will lose only unimportant data. However, you still have to depend on gateway integrity with proprietary systems. This potential point of failure does not exist with pure Internet messaging.
But sending attachments by an all-Internet route is not bulletproof, either. Because of the Internet's distributed nature, each message travels through a number of different servers before reaching its destination. Neither the sender nor the receiver ha
s control over those servers, any of which is capable of introducing errors or losing data. The Internet architecture also makes it difficult to guarantee a maximum time for a message to reach its destination -- a necessity for some companies. "Guaranteed delivery is the most fundamental thing an e-mail system must do," says Scott Welch, president of e-mail vendor SoftArc.
Legacy Roadblocks
Mainframe-based legacy systems, such as IBM's OfficeVision, are more problematic in the way they handle attachments. They usually treat attachments as disconnected routable files that require recipients to manually seek and retrieve them. Companies such as Lotus, Digital Equipment, and Innosoft offer gateway products from systems such as PROFS or VMS Mail, but that adds complexity. Converting addresses from, say, Digital's limited two-part format to an Internet equivalent can be tricky.
It is conceivable that attachments could become irrelevant. Using Java or ActiveX scripts, it is possible to
embed special data types within the body of a mail message. In fact, this feature is available now in Coordinate.com's BeyondMail 3.0. It allows you to send multimedia elements as ActiveX scripts. For now, however, this capability itself is proprietary. Netscape is talking up the benefits of sending Java applets by mail. And last November, Lotus demonstrated a cc:Mail prototype written entirely in Java. It was just a "proof of concept," but Mark McHarry, press-relations manager at Lotus Development, says "that is the future for us."
illustration_link (13 Kbytes)
Gateway Hell
