David L. Mills, who made the Internet run in time, dies at 85

David L. Mills, an Internet pioneer who developed and spent decades implementing the timekeeping protocol used by financial markets, power grids, satellites, and billions of computers to ensure they work simultaneously, earning him a reputation as the Internet's “Father Time” . 'died on January 17 at his home in Newark, Del. He was 85.

His daughter, Leigh Schnitzler, confirmed the death.

Dr. Mills was among the inner circle of computer scientists who, in the 1960s through the 1990s, developed Arpanet, a relatively small network of linked computers in academic and research institutions, and then its global successor, the Internet.

It was challenging enough to develop the hardware and software needed to connect even a small number of computers. But Dr. Mills and his colleagues realized they also had to create the protocols necessary to ensure the devices could communicate accurately.

His focus was on time. Each machine has its own internal clock, but a network of devices should operate simultaneously, to within 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 daily servers. These regularly ping up to a smaller number of more powerful servers, which in turn ping up all the way to another small number of powerful servers linked to a series of timekeeping devices such as atomic clocks.

Based on a consensus time derived from these core devices, the 'official' time then flows back down the hierarchy. The system contains algorithms that detect and correct errors, down 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 en route on routers known as store-and-forward switches – all of which required a degree of programming sophistication on Dr. Mills who even surprised other internet pioneers.

“I was always amazed at the fact that he can actually get very synchronized time out of this store-and-forward system, with variable delays and everything else,” says Vint Cerf, who helped develop some of the first protocols for Arpanet and 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 spent much of his career as a professor at the University of Delaware, not only published the protocol but also updated it regularly over the next two decades—making him the Internet's semi-official timekeeper, though he called himself a called 'internet fat monkey'. .”

The Network Time Protocol was just one of Dr.'s contributions. Mill to the underlying architecture of the Internet. He created the fourth version of the Internet Protocol in 1978, essentially the basic playbook; it is still the dominant version used today.

In the late 1970s, he also created the first modern network router, which formed the backbone of NSFnet, a successor to Arpanet that evolved into the modern Internet. He was a fan of quirky names and called the routers “fuzzballs.”

“It was a sandbox,” he said a 2004 oral history interview, which chronicles the early days of network programming. “And we weren't told essentially what to do. We were just told, 'Do good deeds.' But the good deeds were things like developing electronic mail 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 machinery.

David was born with glaucoma, and although pediatric surgery restored some vision in his left eye, he would use large computer screens throughout his career. He attended a school for the blind in San Mateo, California, where a teacher told him his poor eyesight meant he would never go to college.

He persevered and was admitted to the University of Michigan. There he obtained a bachelor's degree in engineering (1960) and technical mathematics (1961); master's degrees in electrical engineering (1962) and communication sciences (1964); and a PhD in computer and communication sciences (1971).

Computer science was just emerging as a field. It was not fully in existence when he arrived at Michigan, and when he submitted his dissertation 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 his 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 company created to develop satellite communications systems.

Through his work at Comsat he came into close contact with Dr. Cerf and others who worked on Arpanet, which started in 1968 with just four computers at four research institutions and grew to about 40 institutions within a decade.

There was little hierarchy among those early researchers; they coordinated their work via an early version of email and made decisions based on rough consensus. Dr. Mills quickly attached himself to the issue of time 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 East Coast hub for networking research. He retired in 2008, but continued to teach and conduct research.

All his life, Dr. Mills an avid ham radio operator; as a teenager, he connected 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 antenna array on the roof. Up university websitehe joked that “in an emergency, the antenna on the roof can be converted into helicopter rotor blades and bring the house to safety.”