이메일이 X.400이었다면 훨씬 완벽했을 텐데

If the history of email had gone somewhat differently, the last email you sent could have been rescinded or superseded by a newer version when you accidentally wrote the wrong thing. It could have been scheduled to arrive an hour from now. It could have auto-destructed if not read by midnight. You would never have needed to type “as per my previous message.” Instead, you could have linked emails together into a personal Wikipedia of correspondence. You could have messaged an entire organization or department, with your email app ensuring the message was deliverable before it left your outbox. And you could have attached files and written a multilingual message with letters beyond ASCII’s 128 characters, eight years before those features came to internet email. You could have been notified when the message was read a full 15 years before email had something similar tacked on. Encryption would have been baked in from the start, rather than waiting for PGP, S/MIME, and TLS to add them later. All that, and more, was standardized in the 1984 spec for X.400 as Interpersonal Messaging . It was everything we call email today, and then some. “We had a better system back in the day: X.400,” as one commentator reminisced . SMTP, the Simple Mail Transfer Protocol that became the standard behind how modern email is sent, “didn’t win because it was ‘better,’” he argued, but “just because it was easier to implement. Like a car with no brakes or seatbelts.” “Of all the things OSI has produced, one could point to X.400 as being the most successful,” agreed Marshall T. Rose , a developer who helped bridge the differences between X.400 and SMTP email. Differences like X.400 email addresses with bang path-esque addresses like C=no; ADMD=; PRMD=uninett; O=uninett; S=alvestrand; G=harald while SMTP email addresses looked like Harald.Alvestrand@uninett.no . “On the other hand,” he concluded, “that’s kind of like saying that World War II was the successful conclusion of the Great Depression.” Come, let us build a standard Six months before Neil Armstrong stepped on the moon, the United States Department of Defense started building ARPANET, a network to link computers around the country, budgeted from money redirected from missile defense. It was on that network that email as we know it was invented. Ray Tomlinson pulled file transfer software, the ARPANET network, and the @ symbol together, and in 1971 email was born. Soon enough it was taking up more than 3/4th of all ARPANET traffic . “Here was this fantastic infrastructure built at government expense for serious purposes — and these geeks were using it for sending messages to one another,” as John Naughton put it in his Brief History of the Future . Email—or at least the idea of email—took the world by storm. CompuServe offered electronic mail to businesses in 1978 and to consumers a year later, with numeric IDs to message anyone else on their network. Or you could subscribe to The Source (launched in ’78) or MCI Mail (as of ’83) or AppleLink (fashionably late in ’86, then to power the first email to space in ’91). Telecoms and governments joined the rush. By 1982, British Telecom launched their Telecom Gold email solution, and USPS, in a $40 million misstep, tried to monopolize email on paper with E-COM . “Two-thirds or more of the mailstream could be handled electronically,” assumed Congress a mere eleven years after Tomlinson sent the first email. Yet the majority of those emails were messages inside walled gardens. You could email anyone you wanted, as long as they, too, used the same service. Even email’s original home was a mess. “By 1977, the Arpanet employed several informal standards for the text messages (mail) sent among its host computers,” stated RFC 822 , an attempt in 1982 to standardize email. Someone had to make electronic messages speak the same language. In stepped the United Nations. “The establishment in various countries of telematic services and computer-based store-and forward message services in association with public data networks creates a need to produce standards to facilitate international message exchange between subscribers to such services,” opened the document that aimed to standardize email, three layers of bureaucracy removed from the Secretary-General, and for a moment email could have been an international standard. I'm from the government and I'm here to help Email should be clear and concise, says the United Nations today, decades removed from the medium’s chaotic early years. Focused on a single topic, with short, meaningful sentences free from jargon. It should be positive, civil, and formal when appropriate, advises the self-described universal global organization. Under its auspices—via the International Telecommunication Union’s Consultative Committee for International Telephony and Telegraphy committee and the UNESCO-linked International Federation for Information Processing—email was almost standardized in October, 1984 under the X.400 spec that was anything other than concise and jargon-free. “This Recommendation is one of a series of Recommendations and describes the system model and service elements of the message handling system (MHS),” started the ‌ Data Communication Networks Message Handling Systems document that spelled out the X.400 spec, drafted by a committee chaired by Canadian Department of Communications senior advisor V. C. MacDonald and filled with national telecom representatives. “The MHS model uses the techniques of the OSI Reference Model to formally define the layered communication structure used between the model’s functional components.” And so on and so forth, for 266 pages. It took six pages to describe how to address messages without once showing a complete email address (and perhaps that was for the best, since X.400 addresses were varied enough that RFC 1506 identified six common ways to format them). It was convoluted, over-described, and under-specified, right when email most needed simplification. And it was late. Two years earlier, the Simple Mail Transfer Protocol had been spelled out in 68 short pages. “The objective of Simple Mail Transfer Protocol (SMTP) is to transfer mail reliably and efficiently,” wrote University of Southern California research scientist Jon Postel in RFC 821 about the system that built on the ARPANET’s original email protocols and the earlier Mail Transfer Protocol. “The SMTP design is based on the following model of communication: as the result of a user mail request, the sender-SMTP establishes a two-way transmission channel to a receiver-SMTP.” Its email addresses used a refreshingly simple user@domain format. Its syntax spelled out exactly how a simple email should work, and little more. Very quickly, the community effort won out over the committee. Prescribe versus describe “Using the X.400 recommendations themselves is practically impossible in most cases, since just learning to read them takes a fair effort which can be expended only by specialists,” opened Cemil Betanov’s Introduction to X.400 book, published in 1993. “X.400 was conceived as a tool, rather than a product.” X.400’s spec prescribed outcomes, that software shall do this and this shall happen as a result. SMTP typically instead described exactly how things should work. Sending a message, for instance, is described in X.400 as follows, with a description of the desired outcome (envelopes, in X.400, generally stood for what today we’d think of as an email message with headers): The submission interaction is the means by which an originating UA transfers to an MTA the content of a message plus the submission envelope. The submission envelope contains the information the MTS requires to provide the requested service elements. SMTP, on the other hand, describes sending an email with specific command names and interaction steps: There are three steps to SMTP mail transactions. The transaction is started with a MAIL command which gives the s