David L. Mills, an Internet pioneer who developed and, for decades, implemented the timing protocol used by financial markets, power grids, satellites, and billions of computers to ensure they operate simultaneously, earning him the reputation of being the “Father of Time” of the Internet. He died on January 17 at his home in Newark, Delaware. He was 85 years old.
His daughter, Leigh Schnitzler, confirmed the death.
Dr. Mills was part of the inner circle of computer scientists who, between the 1960s and 1990s, developed the Arpanet, a relatively small network of connected computers located in academic and research institutions, and later its global successor, the Internet.
Developing the hardware and software needed to connect even a small number of computers was challenging enough. But Dr. Mills and his colleagues recognized that they also had to create the necessary protocols to ensure the devices could communicate accurately.
His focus was time. Each machine has its own internal clock, but a network of devices would need to run simultaneously, down to a fraction of a millisecond. His answer, first implemented in 1985, was the network time protocol.
The protocol is based on a stratified hierarchy of devices; At the bottom are the daily use servers. These regularly ping up a smaller number of more powerful servers, which in turn ping up again, until they reach another small number of powerful servers linked to a series of timing devices such as atomic clocks.
Based on a consensus time extracted from these central devices, the “official” time then flows down the hierarchy. Within the system there are algorithms that look for errors and correct them, in up to a tenth of a millisecond.
The process is very complicated for several reasons: data moves at different speeds over different types of cables; computers run faster or slower; and data packets can be temporarily held up along the way in routers, known as store-and-forward switches, all of which required a degree of programming sophistication on Dr. Mills' part that amazed even other Internet pioneers.
“I was always amazed by the fact that you can get highly synchronized timing out of this store-and-forward system with variable delays and everything else,” Vint Cerf, who helped develop some of the first protocols for Arpanet and is now a vice president of Google, he said in a telephone interview. “But that's because I didn't fully appreciate the Einsteinian calculations that were being done.”
Dr. Mills, who was a professor at the University of Delaware for much of his career, not only published but also periodically updated the protocol over the next two decades, making him the semi-official timekeeper of the Internet, although he called himself an “internet fat monkey.” .”
The network time protocol was just one of Dr. Mill's contributions to the underlying architecture of the Internet. He created the fourth version of the Internet protocol, essentially his primer, in 1978; remains the dominant version used today.
He also created the first modern network router, in the late 1970s, which provided the backbone of NSFnet, a successor to Arpanet that evolved into the modern Internet. A fan of quirky names, he called routers “fuzz balls.”
“It was a sandbox,” he said in an oral history interview from 2004, which describes the early days of network programming. “And they basically didn't tell us what to do. They simply told us: 'Do good deeds.' But the good deeds were things like developing protocols and email.”
David Lennox Mills was born on June 3, 1938 in Oakland, California. His mother, Adele (Dougherty) Mills, was a pianist and his father, Alfred, sold gaskets used to prevent leaks in machinery.
David was born with glaucoma, and although childhood surgery restored some degree of vision in his left eye, he used large computer screens throughout his career. He attended a school for the blind in San Mateo, California, where a teacher told him that his poor eyesight meant he would never go to college.
He persevered and was accepted to the University of Michigan. There he graduated in engineering (1960) and in mathematical engineering (1961); master's degrees in electrical engineering (1962) and communications sciences (1964); and a PhD in computer and communications sciences (1971).
Computer science was just emerging as a field. It did not fully exist when he arrived at Michigan, and when he submitted his doctoral thesis more than a decade later, it was only the second of its kind ever completed at the university.
He married Beverly Csizmadia in 1965. She and their daughter Leigh survive him, as do their son Keith and brother Gregory.
After teaching for two years at the University of Edinburgh, Dr. Mills spent five years at the University of Maryland before moving in 1977 to Comsat, a federally funded corporation created to develop satellite communications systems.
His work at Comsat brought him into close contact with Dr. Cerf and others working at Arpanet, which began in 1968 with just four computers at four research institutions and grew to include about 40 institutions within a decade.
There was little hierarchy among those early researchers; They coordinated their work through an initial email version and made decisions based on rough consensus. Dr. Mills soon latched onto the timing issue because, he later said, no one else was doing it.
In 1986 he moved to the University of Delaware, which by then had become a major center for networking research on the East Coast. He earned emeritus status in 2008, but continued teaching and conducting research.
Throughout his life, Dr. Mills was a passionate radio amateur; As a teenager he was in contact with Navy Seabees working in Antarctica and connected them to their families in the United States.
His two-story clapboard house in Newark had a huge array of antennas on the roof. About his university websiteHe joked that “in case of emergency, the antenna on the roof can be converted into helicopter rotor blades and lift the house to safety.”
