We had exactly the correct number of attendees for Harlan’s Internet Time Tech Workshop: we filled half of the seats in the lab, so the attendees could complete Phase I of the lab on one set of machines and then move over to the computers on the other side of the lab to complete Phase II. Excellent!
Thanks to everyone who braved the rain to make this workshop a priority in their schedule. I know that all attendees appreciated Harlan—and his assistants—who guided them through first the simple arithmetic stuff and then on through the more complex applications of the basic concepts involved in monitoring Internet Time.
Harlan conceived a very creative way to demonstrate timing within the context of a network: paper airplanes! Attendees first designed and then fabricated their best paper airplane. Next, they created 8 sets of time slots to record send/receive times for the Time Sent from the Client (“T1”), Time Received by the Server (“T2”), Time Sent by the Server (“T3”), and Time Received by the Client (“T4”).
With each person controlling a separate computer (client), they recorded T1 on their airplane, and then launched their plane towards Harlan (who was acting as the server). As a paper airplane landed on target (sometimes with assistance from interstitial routers, in the form of intermediary attendees seated between the launch and Harlan), the recipient (server) pressed the space bar on their computer to capture T2, and then recorded the time. Then Harlan added an arbitrary 4 seconds to T2 to determine T3, and launched the paper airplane back in the direction of the sender. The sender then pressed the space bar on their computer to capture T4.
The key thing the lab demonstrated was how to adjust the system clock on the clients so that the clients were in sync with the server; this was achieved by a program devised by Harland and implemented by one of his German-based colleagues. The program let client controllers (attendees) adjust the frequency and offset by using the arrow, shift and control keys to adjust the time up/down.
Towards the end of the workshop, attendees began asking questions about applications for their new knowledge, and Harlan did not disappoint. He dug deep into his memory to retrieve incidents and stories of how time matters; from medical/legal issues (recorded time of death vs. defibrillator machine time), to navigation issues (in days of yore, using celestial time, sailors might find themselves in an unintended land after trying to plot time based upon moon and stars), and train schedules (ensuring that all of the commuter trains off the main track when the non-stop express train barrels through town). There are more than 40 acknowledged sources of the “correct” time that are used throughout the world, including:
- Military
- GMT
- Celestial
- NIST
- Microsoft SNTP (used by Windows machines)
- NTP (used by linux machines)
- GPS
- Atomic
- USNO NTP Network Time Servers
Harlan Stenn continues to impress his audiences with his encyclopedic knowledge of time issues, and grasp of applications for this knowledge. We welcome Harlan’s interesting presentations!
Author: Karen
Written: 1/15/16
Published: 1/15/16