Aviation came to Denver mainly in the form of mail. Like much of the inland West, the first airfields served a smattering of passenger flights (both expensive and uncomfortable in the 1930s) and a regular schedule of contract mail carriers. Postal Service air mail contracts built many of the nation's major airlines—and its major airports. One of Denver's simple airstrips, Denver Municipal Airport, transformed from a mail stop to a busy airport when Continental Airlines moved its headquarters to Denver 1937, and then again when a modern passenger terminal was completed in 1946. Along the way, it had been renamed for the mayor who oversaw much of its development: Stapleton.

The Second World War, and then the post-war return, brought both a boom in aviation generally and in Denver specifically. The city's population grew by almost 10,000 a year from 1940 to 1960. During the '60s, Stapleton gained an additional runway and a new terminal as the schedule grew from under forty departures a day to over one hundred. When airline deregulation prompted a total restructuring of the industry, both by consolidation and widespread adoption of a "hub and spoke" model, Denver's central location made it an obvious choice of hub. United, Continental, Western, and Frontier Airlines all made Denver Stapleton a busy node in their growing networks.

With growing traffic, Stapleton showed its age. The passenger terminals were too small, but moreover, the field had become cramped. The runways were too close to each other for more than one simultaneous approach during instrument conditions, a bottleneck so severe that bad weather in Denver would cause flight delays that cascaded nationwide. The airfield at Stapleton could not be expanded: a combination of terrain, adjacent land in private ownership, and legal disputes with nearby residents and Adams County (where Stapleton was located) effectively precluded any runway additions or extensions. By the '80s, Southwest Airlines was rapidly expanding beyond its native Texas—but service to Denver was blocked by a lack of available gates at Stapleton.

One of the downsides of having written here for six years now is that my messy, ever-growing text file of topics for future articles contains a bunch of ideas that have been there for about six years. Part of the problem is that I just have to scroll so far up to even see them now, part of it is that some of them are on topics where I do not feel equipped to write a good formal treatment. So let's consider this an easy, breezy episode of Computers Are Bad as I knock out one of those items.

One of these O. G. topics, line three, is "avalanche technology." I will admit that I am a little fuzzy on what this originally meant, but I have a few good guesses. First, though, let's just take a step back and talk a little bit about the practicalities of the avalanche. For a lot of you, avalanches are probably a pretty abstract issue.

For me, as well—I snowboard but I'm not that good at it, and the kind of mid-tier ski area where you will find me tumbling down the hill (Ski Santa Fe, towards Totemoff's) manages their slopes to avoid the potential for avalanche as much as possible. This requires some expertise in avalanche risks and it's never quite perfect, but it's pretty good. Snow that is regularly groomed by machines like PistenBullys will become coherently packed such that avalanches can't really propagate. The bigger risk on groomed ski slopes generally comes from up above, and here in New Mexico our mountains are of such a height that we're usually starting down from the very top anyway.

Still, avalanches pose a real hazard. The Department of Homeland Security, when it can be distracted from terrorizing well-meaning migrants, tells us that avalanches claim about 28 lives each year in the United States. Globally, the number is much larger, and avalanche fatalities seem to be generally more common in Europe. I'm not sure if that reflects European weather, geography, or recreation habits more, but it's the way things pan out and means that Northern Europe tends to be the center of avalanche technology (as it is in alpine technology in general).

Brigadier Martin Hotine is not quite the image of a decorated officer. His name is styled with trailing acronyms that make it no surprise that there is an official portrait, yet in that painting he appears disheveled, his tie far off center in the collar of his jacket. He leans off to one side, not quite like he is sitting for a portrait, but more like he was caught in the middle of something. Photos of the man are often similar: he's distracted, looking down at his desk or staring into space. His mind seems to be elsewhere. Hotine had a lot to think about. His duties in the First and Second World Wars had only been a distraction from the real work of his career: the precise measurement of the whole British Empire.

Late in Hotine's career, he was honored not only by his own country (as a Commander of the Order of the British Empire) but by the United States as well (named an Officer of the Legion of Merit). Most of his awards, though, reflected the technical nature of his work: the Founder's Medal of the Royal Geographical Society, and shortly after his death in 1968, the Gold Medal of the United States Department of Commerce.

Ribbons and medals, though, do not quite capture the breadth of Hotine's work. His greatest memorial is an artifact of his work: squat concrete pillars surmounted by a triangular brass plate. Found atop mountains and hills throughout the United Kingdom, these "trig points," designed by Hotine himself, are the physical references of the Retriangulation of Great Britain. This effort, spanning from 1935 to 1962 with the interruption of WWII, revised an original triangulation (initiated in the 18th century) as the basis for British surveying. Through the course of this effort, Hotine developed methods that would revolutionize the field of geodesy. His collaboration with mapmakers from the United States, a continuation of his wartime surveying for the Allied Forces, set the stage for one of geodesy's most ambitious projects: a measurement taken across the Atlantic Ocean.

During the heyday of AT&T, it was often said that the telephone system was the largest machine ever built. The "hello machine" certainly was vast, but whether or not you consider it to be a single machine raises challenging questions of definition. The Internet, I think we can all agree, is not a single machine but a system of interconnected ones. The telephone network, though, felt a lot more like one device. "One Policy, One System, Universal Service" was once the slogan of AT&T, a message that the telephone network is more than just a sum of parts. The third of these principles, "Universal Service," is a key point around which telecom policy pivots even today. As the telephone system was at its apex, Universal Service became its undoing.

We know the Internet to be a network of independent devices in part because of the wide variety of ways that we access it. Computer networks, almost to their origin, have emphasized independent implementations of standardized interfaces. Computers, as network nodes, are interchangeable. As a result, much of the complexity must be pushed to the edge, where end-user systems are most able to adapt to the unique needs of, well, the end-user. The telephone system was much different: few types of telephone instrument existed, largely from a single manufacturer. Complexity was drawn into the center where telephone offices could house the huge machinery required by mid-century automation. All of it was, for a very long time, hard-wired: central office switches and customer telephones were designed and installed to suit each other. This core difference, between the flexibility of computer networks and the central caretakership of telephone networks, was a core issue in the series of changes that rocked the telephone business in the early 1980s.

1984 is the K/T line of telecommunications, the year the sea peoples came. It is difficult to overstate the extent to which telephone technology, the communications industry, and the basic concept of what a telephone is changed between the 1970s and the 1980s. This was not a single, well-planned, carefully executed reform the way some accounts of divestiture can make it out to be. In practice, it was chaotic, messy, and often drawn out.

Email, one of the most pervasive and enduring technologies of computer networking, was invented in about a dozen places by dozens of people in the 1960s. It's hard to lay out a clear history of the technology because it's just so obvious—pretty much as soon as more than one person could use a computer, there was some kind of mail facility. These ranged from mainframe-centric systems where all of the users of a single computer could write messages to each other, to PC-centric systems where workstations would mount a network share to store and retrieve messages. Pretty much any scheme you can come up with for moving messages was probably in use somewhere from roughly the 1960s to the 1990s, by which time the ARPANET-derived family of email implementations had taken hold.

This form of email has a clearer heritage, to Ray Tomlinson, who came up with the core idea that addresses could identify both a user and a host, and that some kind of open protocol could be used to send messages to another host when necessary. Over time, and with many revisions, Tomlinson's design became SMTP and was joined by protocols like IMAP that built out the form of email we use today. This is a form of email that is in some ways decentralized (any user is free to choose a host) and in other ways centralized (each host assumed to be continuously online to store-and-forward messages for its users). Tomlinson's design was flexible enough that we have not had to totally get rid of it, but enough has changed about the modern Internet that we have had to take a new approach.

Email has many vexing limitations, artifacts of its age. For example, email handling should not be assumed to be "8-bit clean"—email protocols were originally defined over 7-bit ASCII and ran on many machines that used the eighth bit as a checksum. These machines were prone to changing the last bit of each byte, or otherwise mishandling email with 8-bit content. That wasn't a problem when text was completely limited to that 7-bit plane, but both Unicode and the desire to send binary files made 7-bit email unworkable. MIME was developed as a workaround, an encoding technique that solves a few problems in one go by encoding all non-ASCII content of email in the form of ASCII characters.