Communications of the ACM
Why Computers Still Struggle to Tell the Time
Software engineer George Neville-Neil is working on an IEEE standard for relaying the time over a network that is more accurate than the industry standard Network Time Protocol.
Credit: Japan Trend Shop
Despite the extreme precision of most modern computer systems, software engineer George Neville-Neil says it remains surprisingly difficult for them to accurately tell time.
Speaking at ACM's Applicative conference in New York City last week, Neville-Neil said the problem stems largely from the hardware most computers use to tell time: often inexpensive crystal oscillators that lose precision over time. He says the average computer, smartphone, or server is able to tell time as accurately as a mechanical pocket watch, which is adequate for the average user but not precise enough for many fields.
Energy and telecom companies need nanosecond-level precision, as do cloud-service providers, high-frequency traders, and many robotic systems. The current solution is the use of protocols that regularly query more accurate timekeepers, such as the U.S. Naval Observatory or the National Institute of Standards and Technology.
The most commonly used protocol, Network Time Protocol, queries a master timekeeper once every 15 to 64 seconds and uses the answer to synchronize timekeeping across a network. However, even this process can prove to be insufficient, with many cloud providers struggling to accurately keep time.
Neville-Neil is developing a more accurate protocol, Precision Time Protocol, which largely relies on querying the master timekeeper more frequently, although this requires more bandwidth.
From PC World
View Full Article
Abstracts Copyright © 2015 Information Inc., Bethesda, Maryland, USA
No entries found