London 2012 will be the 30th modern Olympic Games, and in its 116-year history, UY98UZDDVGGJ the Olympics have gone through many changes. New events have been introduced, records have been broken and different cities have played host to the games, but one constant has remained – the need to time competitors accurately during the different events. (more…)
Archive for the ‘Time Synchronisation’ Category
All sorts of technologies rely on precise and exact time, from cash machines and CCTV cameras, to speed cameras and computer networks. For computer networks, accurate time is essential for preventing errors, fraud and ensures security. Without it, many organisations, industries and modern applications couldn’t function. Everything from internet banking to air traffic control relies on precise and accurate time, but many organisations take unnecessary risks when it comes to the time on their networks and rely on online time servers. (more…)
Accurate time is important for many organisations, but keeping precise time in a school, office or business can be a challenge. Standard clocks are not as reliable as most people think. Often, battery powered quartz clocks will drift, sometimes by several minutes a week, which affects the timekeeping of people. (more…)
GPS time servers are a highly accurate and secure method of synchronising a computer network to UTC (Coordinated Universal Time). GPS time servers are simple to use and ensure a network is synchronised to s secure form of time. However, many network administrators don’t see the need to use a GPS time server and continue to put their network at risk by using an online source of time for synchronisation. Here are five reasons why a GPS time server is crucial for computer network synchronisation. (more…)
Time synchronisation is something easily taken for granted in this day and age. With GPS NTP servers, satellites beam down time to technologies, which keeps them synced to the world’s time standard UTC (Coordinated Universal Time).
Before UTC, before atomic clocks, before GPS, keeping time synchronised was not so easy. Throughout history, humans have always kept track of time, but accuracy was never that important. A few minutes or an hour or so difference, made little difference to people’s lives throughout the medieval and regency periods; however, come the industrial revolution and the development of railways, factories and international commerce, accurate timekeeping became crucial.
Greenwich Mean Time (GMT) became time standard in 1880, taking over from the world’s first time standard railway time, developed to ensure accuracy with railway timetables. Soon, all businesses, shops and offices wanted to keep their clocks accurate to GMT, but in an age before electrical clocks and telephones, this proved difficult.
Enter the Greenwich Time Lady. Ruth Belville was a businesswoman from Greenwich, who followed in her father’s footsteps in delivering time to businesses throughout London. The Belville’s owned a highly accurate and expensive pocket watch, a John Arnold chronometer originally made for the Duke of Sussex.
Every week, Ruth, and her father before her, would take the train to Greenwich where they would synchronise the pocket watch to Greenwich Mean Time. The Belvilles would then travel around London, charging businesses to adjust their clocks their chronometer, a business enterprise that lasted from 1836 to 1940 when Ruth finally retired at the age of 86.
BY this time, electronic clocks had began to take over traditional mechanical devices and were more accurate, needing less synchronisation, and with the telephone speaking clock introduced by the General Post Office (GPO) in 1936, timekeeping services like the Belville’s became obsolete.
Today, time synchronisation is far more accurate. Network time servers, often using the computer protocol NTP (Network Time Protocol), keep computer networks and modern technologies true. NTP time servers receive an accurate atomic clock time signal, often by GPS, and distribute the time around the network. Thanks to atomic clocks, NTP time servers and the universal timescale UTC, modern computers can keep time to within a few milliseconds of each other.
Despite the use of UTC (Coordinated Universal Time) as the world’s timescale, time zones, the regional areas with a uniform time, are still an important aspect of our daily lives. Time zones provide areas with a synchronised time that helps commerce, trade and society function, and allow all nations to enjoy noon at lunchtime. Most of us who have ever gone abroad are all aware of the differences in time zones and the need to reset our watches.
Keeping track of time zones can be really tricky. Different nations not only use different times but also use different adjustments for daylight saving, which can make keeping track of time zones difficult. Furthermore, nations occasionally move time zone, normally due to economic and trade reasons, which provides even more difficulties in keeping track of time zones.
You may think that modern computers can automatically account for time zones due to the settings in the clock program; however, most computer systems rely on a database, which is continuously updated, to provide accurate time zone information.
The Time Zone Database, sometimes called the Olson database after its long-time coordinator, Arthur David Olson, has recently moved home due to legal wrangling, which temporarily caused the database to cease functioning, causing untold problems for people needing accurate time zone information. Without the time zone database, time zones had to be calculated manually, for travelling, scheduling meetings and booking flights.
The Internet’s address system, ICANN (Internet Corporation for Assigned Names and Numbers) has taken over the database to provide stability, due to the reliance on the database by computer operating systems and other technologies; the database is used by a range of computer operating systems including Apple Inc’s Mac OS X, Oracle Corp, Unix and Linux, but not Microsoft Corp’s Windows.
The Time Zone Database provides a simple method of setting the time on a computer, enabling cities to be selected, with the database providing the right time. The database has all the necessary information, such as daylight saving times and the latest time zone movements, to provide accuracy and a reliable source of information.
Or course, a synchronised computer networks using NTP doesn’t require the Time Zone Database. Using the standard international timescale, UTC, NTP servers maintain the exact same time, no matter where the computer network is in the world, with the time zone information calculated as a difference to UTC.
International Telecommunications Union (ITU), based in Geneva, is voting in January to finally get rid of the leap second, effectively scrapping Greenwich Meantime.
UTC (Coordinated Universal Time) has been around since the 1970’s, and already effectively governs the world’s technologies by keeping computer networks synchronised by way of NTP time servers (Network Time Protocol), but it does have one flaw: UTC is too accurate, that is to say, UTC is governed by atomic clocks, not by the rotation of the Earth. While atomic clocks relay an accurate, unchanging form of chronology, the Earth’s rotation varies slightly from day-to-day, and in essence is slowing down by a second or two a year.
To prevent noon, when the sun is highest in the sky, from slowly getting later and later, Leap Seconds are added to UTC as a chronological fudge, ensuring that UTC matches GMT (governed by when the sun is directly above by the Greenwich Meridian Line, making it 12 noon).
The use of leap seconds is a subject of continuous debate. The ITU argue that with the development of satellite navigation systems, the internet, mobile phones and computer networks all reliant on a single, accurate form of time, a system of timekeeping needs to be precise as possible, and that leap seconds causes problems for modern technologies.
This against changing the Leap Second and in effect retaining GMT, suggest that without it, day would slowly creep into night, albeit in many thousands of years; however, the ITU suggest that large-scale changes could be made, perhaps every century or so.
If leap seconds are abandoned, it will effectively end Greenwich Meantime’s guardianship of the world’s time that has lasted over a century. Its function of signalling noon when the sun is above the meridian line started 127 years ago, when railways and telegraphs made a requirement for a standardised timescale.
If leap seconds are abolished, few of us will notice much difference, but it may make life easier for computer networks that synchronised by NTP time servers as Leap Second delivery can cause minor errors in very complicated systems. Google, for instance, recently revealed it had written a program to specifically deal with leap seconds in its data centres, effectively smearing the leap second throughout a day.
Leap Seconds have been in use since the development of atomic clocks and the introduction of the global timescale UTC (Coordinated Universal Time). Leap Seconds prevent the actual time as told by atomic clocks and the physical time, governed by the sun being highest at noon, from drifting apart.
Since UTC began in the 1970’s when UTC was introduced, 24 Leap Seconds have been added. Leap seconds are a point of controversy, but without them, the day would slowly drift into night (albeit after many centuries); however, they do cause problems for some technologies.
NTP servers (Network Time Protocol) implement Leap Seconds by repeating the final second of the day when a Leap Second is introduced. While Leap Second introduction is a rare event, occurring only once or twice a year, for some complex systems that process thousands of events a second this repetition causes problems.
For search engine giants, Google, Leap Seconds can lead to their systems from working during this second, such as in 2005 when some of its clustered systems stopped accepting work. While this didn’t lead to their site from going down, Google wanted to address the problem to prevent any future problems caused by this chronological fudge.
Its solution was to write a program that essentially lied to their computer servers during the day of a Leap Second, making the systems believe the time was slightly ahead of what the NTP servers were telling it.
This gradual speeding up time meant that at the end of a day, when a Leap Second is added, Google’s timeservers do not have to repeat the extra second as the time on its servers would already be a second behind by that point.
Whilst Google’s solution to the Leap Second is ingenious, for most computer systems Leap Seconds cause no problems at all. With a computer network synchronised with an NTP server, Leap Seconds are adjusted automatically at the end of a day and occur only rarely, so most computer systems never notice this small hiccup in time.
Researchers have discovered that the British atomic clock controlled by the UK’s National Physical Laboratory (NPL) is the most accurate in the world.
NPL’s CsF2 caesium fountain atomic clock is so accurate that it wouldn’t drift by a second in 138 million years, nearly twice as accurate as first thought.
Researchers have now discovered the clock is accurate to one part in 4,300,000,000,000,000 making it the most accurate atomic clock in the world.
The CsF2 clock uses the energy state of caesium atoms to keep time. With a frequency of 9,192,631,770 peaks and troughs every second, this resonance now governs the international standard for an official second.
The international standard of time—UTC—is governed by six atomic clocks, including the CsF2, two clocks in France, one in Germany and one in the USA, so this unexpected increase in accuracy means the global timescale is even more reliable than first thought.
UTC is essential for modern technologies, especially with so much global communication and trade being conducted across the internet, across borders, and across timezones.
UTC enables separate computer networks in different parts of the world to keep exactly the same time, and because of its importance accuracy and precision is essential, especially when you consider the types of transactions now conducted online, such as the buying of stocks and shares and global banking.
Receiving UTC requires the use of a time server and the protocol NTP (Network Time Protocol). Time servers receive a source of UTC direct from atomic clocks sources such as NPL, who broadcast a time signal over long wave radio, and the GPS network (GPS satellites all transmit atomic clock time signals, which is how satellite navigation systems calculate position by working out the difference in time between multiple GPS signals.)
NTP keeps all computers accurate to UTC by continuously checking each system clock and adjusting for any drift compared to the UTC time signal. By using an NTP time server, a network of computers is able to remain within a few milliseconds of UTC preventing any errors, ensuring security and providing an attestable source of accurate time.
The stock market has been in the news a lot lately. As global uncertainty about national debts rise, the markets are in flux, with prices changing incredibly quickly. On a trading floor, every second counts and precise time is essential for global buying and selling of commodities, bonds and shares.
The international stock exchanges such as the NASDAQ and London Stock Exchange all require accurate and precise time. With traders buying and selling shares for customers across the globe, a few seconds of inaccuracy could cost millions as share prices fluctuate.
NTP servers linked to atomic clock timing signals ensure that the stock exchange keeps an accurate and precise time. As computers across the globe all receive the stock prices, as and when they change, these two use NTP server systems to maintain time.
The global timescale UTC (Coordinated Universal Time) is used as the basis for atomic clock timing, so no matter where a trader is on the globe, the same timescale prevents confusion and errors when dealing with stocks and shares.
Because of the billions of pounds worth of stocks and shares that are bought and sold on trading floors every day, security is essential. NTP servers work externally to networks, getting their time from sources such as GPS (Global Positioning System) or radio signals put out by organisations like the National Physical Laboratory (NPL) or the National Institute for Standards and Time (NIST).
The stock exchanges can’t use a source of internet because of the risk this could pose. Hackers and malicious users could tamper with the time source, leading to mayhem and cost millions and perhaps billions if the wrong time was spread around the exchanges.
The precision of internet time is limited too. Latency over distance can create delays, which could lead to errors, and if the time source ever went down, the stock markets could hit trouble.
It is not only stock markets that need precise and accurate time, computer networks across the globe concerned about security use dedicated NTP servers like Galleon Systems’ NTS 6001. Providing accurate time from both GPS and radio signals from NPL and NIST, the NTS 6001 ensure accurate, precise and secure time every day of the year.