David L., who keeps the Internet running on time. Mills dies at the age of 85
David L. Mills, an Internet pioneer who for decades developed and implemented the timekeeping protocols used by financial markets, power grids, satellites, and billions of computers to ensure that they run together, making them part of the Internet. Earned a reputation as “Father Time”. He died at his home in Newark, Del., on January 17. He was 85 years old.
His daughter Leigh Schnitzler confirmed the death.
Dr. Mills was among the inner group 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 world-wide successor, the Internet. Developed.
Developing the hardware and software required to connect the small number of computers was quite challenging. But Dr. Mills and his colleagues recognized that they also had to create the necessary protocols to ensure that the devices could communicate accurately.
His focus was on time. Each machine has its own internal clock, but a network of devices would need to operate simultaneously, down to a fraction of a millisecond. Their answer, first implemented in 1985, was the Network Time Protocol.
The protocol relies on a stratified hierarchy of devices; At the bottom are the everyday servers. These regularly ping upward to a small number of more powerful servers, which in turn ping upward again to another small number of powerful servers connected to a series of timekeeping devices such as atomic clocks.
Based on the consensus time extracted from these main devices, the “official” time then flows back up the hierarchy. There are algorithms within the system that look for errors and correct them down to tenths of a millisecond.
This process is highly complex for several reasons: data moves at different speeds over different types of cables; Computers work faster or slower; And packets of data can be temporarily placed en route to routers, known as store-and-forward switches – all of which requires a degree of programming sophistication on Dr. Mills' part, Which surprised even other Internet pioneers.
Vint Cerf, who helped develop some of the early protocols for the Arpanet and is now one of the first, says, “I was always amazed by the fact that he really got this store-and-forward system with variable delays and highly synchronized everything else. Can get time.” the Google vice president said in a phone 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 most of his career, not only published but also regularly updated the protocol over the next two decades – making him the semi-official timekeeper of the Internet, although he himself Said “Internet Greece Monkey”. ,
The Network Time Protocol was only one of Dr. Mill's contributions to the underlying architecture of the Internet. He created the fourth version of the Internet Protocol, essentially its basic playbook, in 1978; This is the major version still in use today.
He also built the first modern network router in the late 1970s, which provided the backbone of NSFNet, the successor to ARPANET that evolved into the modern Internet. A fan of quirky names, he called the routers “fuzzballs”.
“It was a sandbox,” he said 2004 oral history interview, describing the early days of network programming. “And we weren't necessarily told what to do. We are simply told, 'Do good deeds.' But the good work was things like electronic mail and developing 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 he had some vision restored in his left eye after childhood surgery, he used sizable computer screens throughout his career. He attended a school for the blind in San Mateo, California, where a teacher told him that his poor vision meant he would never be able to attend college.
He persevered and was accepted into the University of Michigan. There he obtained bachelor's degrees in engineering (1960) and engineering mathematics (1961); postgraduate degrees in Electrical Engineering (1962) and Communication Science (1964); and a doctoral degree in Computer and Communication 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 dissertation more than a decade later, it was only the second of its kind ever completed at the university.
He married Beverly Szymadia in 1965. Along with his daughter Leigh, he is survived by his 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 corporation 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 with just four computers at four research institutes in 1968 and grew to include nearly 40 institutes within a decade .
There was little hierarchy among those first researchers; They coordinated their work on an early version of the email and made decisions based on consensus. Dr. Mills soon concerned himself with the question of timing because, he later said, no one else was doing it.
In 1986 he moved to the University of Delaware, which by that time had become an important East Coast center for networking research. He took emeritus status in 2008 but continues to teach and research.
Throughout his life, Dr. Mills was an avid ham radio operator; As a teenager he was exposed to Navy Seabees working in Antarctica and introduced them to their families in the United States.
His clapboard, two-story house in Newark had a giant antenna on the roof. on him University websiteHe joked that “in an emergency, the roof antenna could be converted into helicopter rotor blades and the house could be lifted to safety.”