David L. Mills, who kept the Internet running in time, dies at 85

He developed and implemented the protocol that synchronizes digital clocks nestled in billions of networked devices.

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 work simultaneously, earning him the reputation as the "father of time" of the Internet. ", died Jan. 17 at his home in Newark, Del. He was 85.

His daughter, Leigh Schnitzler, confirmed the death.

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

< p class="css-at9mc1 evys1bk0">It was already a real challenge to develop the hardware and software necessary 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 that the devices could communicate accurately.

His goal was time. Each machine has its own internal clock, but a network of devices should operate simultaneously, to the nearest 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 .

Based on a consensus time taken from these main devices, the “official” time then moves down the hierarchy. Tucked into the system are algorithms that look for errors and correct them, down to the tenth of a millisecond.

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