David L. Mills, Internet pioneer who developed and implemented for decades the timing protocol used by financial markets, power grids, satellites, and billions of computers to ensure they operate simultaneously, earning him the reputation of “Father Time ” of the Internet. » died Jan. 17 at his home in Newark, Del. He was 85 years old.
His daughter, Leigh Schnitzler, confirmed the death.
Dr. Mills was among the small circle of computer scientists who from the 1960s to the 1990s developed the Arpanet, a relatively small network of connected computers located in academic and research institutions, and then its worldwide successor, the Internet.
It was quite difficult to develop the hardware and software required to connect even a small number of computers. But Dr. Mills and his colleagues recognized that they also had to create the necessary protocols to make sure the devices could communicate accurately.
His focus was time. Each machine has its own internal clock, but a network of devices should work simultaneously, down to the millisecond. His answer, first implemented in 1985, was the Network Time Protocol.
The protocol is based on a layered hierarchy of devices. at the bottom are daily servers. These regularly ping upwards to a smaller number of stronger servers, which in turn ping upwards to another small number of powerful servers connected to a series of timekeeping devices such as atomic clocks.
Based on a consensus time derived from these key devices, the “official” time then flows back up the hierarchy. Inside the system are algorithms that look for errors and correct them, 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 to routers known as store-and-forward switches — all of which required a degree of programming sophistication on the part of Dr. Mills that surprised even other Internet pioneers.
“It’s always amazed me that you can actually get a lot of synchronized time out of this store-and-forward system with variable delays and everything,” Vint Cerf, who helped develop some of the early protocols for the Arpanet and is now vice president of Google, he said in a telephone interview. “But that’s because I didn’t fully appreciate the Einstein calculations that were going on.”
Dr. Mills, who was a professor at the University of Delaware for much of his career, not only published but regularly updated the protocol over the next two decades—making him the Internet’s semi-official timekeeper, though he called himself the “fat monkey of the Internet.” .”
The network time protocol was just one of Dr. Mill in the underlying architecture of the Internet. He created the fourth version of the Internet protocol, essentially its core book, in 1978. It is still the dominant version in use 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 lover of quirky names, he called the routers “fuzzballs”.
“It was a sandbox,” he said in a 2004 oral history interview, describing the network’s early programming days. “And they basically didn’t tell us what to do. We were simply told “Do good deeds.” But the good deeds were things like the development of e-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 childhood 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 persisted and was accepted to the University of Michigan. There he received degrees in engineering (1960) and engineering mathematics (1961). Masters in Electrical Engineering (1962) and Communications Science (1964). and PhD in computer and communications science (1971).
Computer science was just emerging as a field. It didn’t fully exist when he arrived at Michigan, and when he submitted his doctoral 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. Along with their daughter, Leigh, he survives, 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.
His work at Comsat brought him into close contact with Dr. Cerf and others working on the Arpanet, which began in 1968 with just four computers at four research institutions and grew to about 40 institutions within a decade.
There was little hierarchy among these early researchers. they coordinated their work on an early version of email and made decisions based on rough consensus. Dr. Mills soon latched onto the timing issue because, he later said, no one else did.
In 1986 he moved to the University of Delaware, which by then had become a major East Coast hub for networking research. He received emeritus status in 2008, but continued to teach and conduct research.
Throughout his life, Dr. Mills was an avid radio operator. As a teenager he was in contact with Navy Seabees working in Antarctica and sent them to their families in the United States.
His two-story house in Newark had a huge antenna array on its roof. On his university’s website, he joked that “in emergencies, the roof antenna can turn into helicopter rotor blades and lift the house to safety.”
