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 that they operate simultaneously, earning him the reputation of “Father of Time,” died Jan. 17 at his home in Newark, Del. He was 85 years old.
His daughter, Leigh Schnitzler, confirmed the death.
Dr. Mills was part of the inner circle of computer scientists who, from the 1960s to the 1990s, developed Arpanet, a relatively small network of linked computers located in academic and research institutes, and then its global successor, Internet.
It was difficult enough to develop the hardware and software needed to connect even a small number of computers. But Dr. Mills and his colleagues recognized that they also needed to create the necessary protocols to ensure the devices could communicate accurately.
His goal was time. Each machine has its own internal clock, but a network of devices should be running simultaneously, down to the fraction of a millisecond. Its answer, first implemented in 1985, was the Network Time Protocol.
The protocol relies on a stratified hierarchy of devices. Downstairs are the everyday servers. These regularly ping up to a smaller number of more powerful servers, which in turn ping upwards, to another small number of powerful servers linked to a set of timekeeping devices like atomic clocks .
On the basis of a consensual time taken from these central apparatuses, the “official” time then goes down the hierarchy. Within the system are algorithms that look for errors and correct them to the nearest tenth of a millisecond.
The process is very complicated for several reasons: data moves at different speeds on different types of cables; computers run faster or slower; and data packets can be held temporarily en route on routers, known as store-and-forward switches, which required a degree of programming sophistication on Dr. Mills’ part that amazed even d other Internet pioneers.
“I was always amazed that he could actually get highly synchronized time from 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 at Google, 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 regularly updated the protocol over the next two decades, making him the semi-official timekeeper of ‘Internet, although he calls himself the “fat monkey of the Internet.” . » .
The Network Time Protocol was just one of Dr. Mills’ contributions to the underlying architecture of the Internet. He created the fourth version of the Internet Protocol, essentially its basic manual, in 1978; this is still the dominant version used today.
He also created the first modern network router, in the late 1970s, which forms the backbone of NSFnet, Arpanet’s successor that evolved into the modern Internet. A fan of original names, I called routers “fuzzballs”.
“It was a sandbox,” he said in a 2004 oral history interview, describing the beginnings of network programming. “And we were basically not told what to do. We were simply told: “Do good deeds. » But the good deeds were the development of email and protocols.
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 machines.
David was born with glaucoma, and although childhood surgery allowed him to regain some degree of sight in his left eye, he used oversized 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 earned a bachelor’s degree in engineering (1960) and engineering mathematics (1961); master’s degrees in electrical engineering (1962) and communications sciences (1964); and a doctorate in computer science and communication sciences (1971).
Computer science was just starting to become a field. It did not fully exist when he arrived at Michigan, and when he submitted his doctoral dissertation more than a decade later, it was only the second such dissertation ever done at the university.
He married Beverly Csizmadia in 1965. She survives him with their daughter, as do their son, Keith, and his brother, Gregory.
After teaching for two years at the University of Edinburgh, Dr. Mills spent five years at the University of Maryland before joining Comsat in 1977, a federally funded company established to develop communications systems satellite.
His work at Comsat brought him into close contact with Dr. Cerf and others working on Arpanet, which began in 1968 with just four computers at four research institutes and grew to include about 40 institutions in one decade.
There was little hierarchy among these early researchers; they coordinated their work on an early version of the email and made decisions based on rough consensus. Dr. Mills quickly focused on the issue of time because, he later said, no one else was doing it.
In 1986, he joined the University of Delaware, which by then had become an important East Coast hub for networking research. He achieved emeritus status in 2008 but continued to teach and conduct research.
Throughout his life, Dr. Mills was an ardent amateur radio operator; As a teenager, he was in contact with Navy Seabees working in Antarctica and passed them on to their families in the United States.
His two-story wooden house in Newark had a huge antenna array on its roof. On his university websitehe joked that “in an emergency, the roof antenna can be converted into helicopter rotor blades and make the house safe.”
