August 11, 2021 - Facebook engineers have shared that they have built and open sourced the entire specification for Time cards, a time device for network synchronization based on ultra-precise atomic clocks and timing technology from navigation satellites that will help accelerate services on the massive Internet.

Every digital device needs to know what time it is, and with the dimension of time, the device can properly provide various services and record various types of logs. Especially for a social network the size of Facebook with billions of users, it is impossible to coordinate data centers without accurate time, so Facebook decided to build its own timekeeping device.

NTP and Stratum One have their shortcomings

Before Time cards were shared, there were basically two ways to check time. Developers would use NTP (Network TimeProtocol) as a time checking mechanism, but this public NTP pool increased the reliance on Internet connectivity and could affect the overall security and reliability of the system.

Companies running closed data centers will have a hardware device called Stratum One acting as a timekeeper. But they’ve been built by a handful of companies over the years, so it’s hard to get new features, and because they’re proprietary in nature, companies like Facebook have no control over these boxes.

New Time cards are more accurate and cheaper

Time Cards are essentially electronic boards that are installed into servers using the same PCI Express expansion card technology that is used to insert graphics cards and other devices.Facebook refers to servers with Time Cards inserted and running their timing software as time devices.

The Time Card is kept in sync by listening to timing information embedded in the radio signals of GNSS navigation satellites. The Time Cards lurk deep within the data center, but they are connected to a roof-mounted antenna to receive the satellite signals. Afterwards, a set of electronic components, including a miniature atomic clock, processes the acquired data for use by the data center servers.

The specifications, schematics, bill of materials (BoM), and source code for the Time Card are currently hosted on the GitHub repository. If the average developer doesn’t need the level of time accuracy that Facebook does, they can get the cost down to about $300 by switching to a more traditional crystal oscillator.

Facebook engineer says: hope to help more people through open source work

Facebook says that building a device that is very accurate, inexpensive and vendor-independent is an achievement in itself.

They decided early on to make the design process open source so that other companies and engineers could contribute to the design. This move shows the collaborative spirit of most companies on the Internet. Even though there will be fierce competition between companies like Facebook, Microsoft and Google, they will contribute to open source projects that can benefit their competitors. The best example of this is Linux, the largest open source software project on a global scale, which is the basis for Android phones, SpaceX spacecraft, supercomputers and countless data center server operating systems. It can be said that open source has led to significant global and ongoing changes in the field of information technology and is playing an increasingly important role in building social infrastructure.

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