The big advantage of a digital network wall clock is that they never have to be set as the time is kept and maintained by the network time server, which ensure the wall clock is accurate to the millisecond. Furthermore, most digital network wall clocks use the power over Ethernet system to provide the clock’s power, so there is no need to wire them up to the mains or install batteries
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.
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 construction of clock, designed to tell the time for 10,000 years, is underway in Texas. The clock, when built, will stand over 60 metres tall and will have a clock face nearly three metres across.
Built by a non-profit organisation, the Long Now Foundation, the clock is being built so as to, not only still be standing in 10,000 years, but also still be telling the time.
Consisting of a 300kg gear wheel and a 140kg steel pendulum, the clock will tick every ten seconds and will feature a chime system that will allow 3.65 million unique chime variations—enough for 10,000 years of use.
Inspired by ancient engineering projects of the past, such as the Great Wall of China and the Pyramids—objects designed to last, the clock’s mechanism will feature state-of-the-art materials that don’t require lubrication of servicing.
However, being an mechanical clock, the Long Now Clock will not be very accurate and will require resetting to avoid drift otherwise the time in 10,000 years will not represent the time on Earth.
Even atomic clocks, the world’s most accurate clocks, require help in preventing drift, not because the clocks themselves drift—atomic clocks can remain accurate to a second for 100 million years, but the Earth’s rotation is slowing.
Every few years an extra second is added to a day. These Leap Seconds inserted on to UTC (Coordinated Universal Time) prevent the timescale and the movement of the Earth from drifting apart.
UTC is the global timescale that governs all modern technologies from satellite navigation systems, air traffic control and even computer networks.
While atomic clocks are expensive laboratory-based machines, receiving the time from an atomic clock is simple, requiring only a NTP time server (Network Time Protocol) that uses either GPs or radio frequencies to pick up time signals distributed by atomic clock sources. Installed on a network, and NTP time server can keep devices running to within a few milliseconds of each other and of UTC.
If you’ve ever tried to keep track of time without a watch or clock, you’ll realise just how difficult it can be. Over a few hours, you may get to within half an hour of the right time, but precise time is very difficult to measure without some form of chronological device.
Before the use of clocks, keeping time was incredibly difficult, and even losing track of days of the years became easy to do unless you kept as daily tally. But the development of accurate timepieces took a long time, but several key steps in chronology evolved enabling closer and closer time measurements.
Today, with the benefit of atomic clocks, NTP servers and GPS clock systems, time can be monitored to within a billionth of a second (nanosecond), but this sort of accuracy has taken mankind thousands of years to accomplish.
With no appointments to keep or a need to arrive at work on time, prehistoric man had little need for knowing the time of day. But when agriculture started, knowing when to plant crops became essential for survival. The first chronological devices such as Stonehenge are believed to have been built for such a purpose.
Identifying the longest and shortest days of the year (solstices) enabled early farmers to calculate when to plant their crops, and probably provided a lot of spiritual significance to such events.
The provided the first attempts at keeping track of time throughout the day. Early man realised the sun moved across the sky at regular paths so they used it as a method of chronology. Sundials came in all sorts of guises, from obelisks that cast huge shadows to small ornamental sundials.
The first true attempt at using mechanical clocks appeared in the thirteenth century. These used escapement mechanisms and weights to keep time, but the accuracy of these early clocks meant they’d lose over an hour a day.
Clocks first became reliable and accurate when pendulums began appearing in the seventeenth century. While they would still drift, the swinging weight of pendulums meant that these clocks could keep track of first minutes, and then the seconds as engineering developed.
Electronic clocks using quartz or other minerals enabled accuracy to parts of a second and enabled scaling down of accurate clocks to wristwatch size. While mechanical watches existed, they would drift too much and required constant winding. With electronic clocks, for the first time, true hassle free accuracy was achieved.
Keeping time to thousands, millions and even billion parts of a second came when the first atomic clocks arrived in the 1950’s. Atomic clocks were even more accurate than the rotation of the Earth so Leap Seconds needed developing to make sure the global time based on atomic clocks, Coordinated Universal Time (UTC) matched the path of the sun across the sky.
The argument about the use of the Leap Second continues to rumble on with astronomers again calling for the abolition of this chronological ‘fudge.’
The Leap Second is added to Coordinated Universal Time to ensure the global time, coincides with the movement of the Earth. The problems occur because modern atomic clocks are far more precise than the rotation of the planet, which varies minutely in the length of a day, and is gradually slowing down, albeit minutely.
Because of the differences in time of the Earth’s spin and the true time told by atomic clocks, occasional seconds need adding to the global timescale UTC—Leap Seconds. However, for astronomers, leap seconds are a nuisance as they need to keep track of both the Earth’s spin—astronomical time—to keep their telescopes fixed on studied objects, and UTC, which they need as atomic clock source to work out the true astronomical time.
Next year, however, a group of astronomical scientists and engineers, plan to draw attention to the forced nature of Leap Seconds at the World Radiocommunication Conference. They say that as the drift caused by not including leap seconds would take such a long time—probably over a millennia, to have any visible effect on the day, with noon gradually shifting to afternoon, there is little need for Leap Seconds.
Whether Leap Seconds remain or not, getting an accurate source of UTC time is essential for many modern technologies. With a global economy and so much trade conducted online, over continents, ensuring a single time source prevents the problems different time-zones could cause.
Making sure everybody’s clock reads the same time is also important and with many technologies millisecond accuracy to UTC is vital—such as air traffic control and international stock markets.
NTP time servers such as Galleon’s NTS 6001 GPS, which can provide millisecond accuracy using the highly precise and secure GPS signal, enable technologies and computer networks to function in perfect synchronicity to UTC, securely and without error.
Security is an essential aspect for any computer network. With so much data now available online, giving ease of access to permitted users, it is important to prevent unauthorised access. Failure to secure a computer network can lead to all sorts of problems for a business, such as data theft, or the network crashing and preventing authorised users from working.
Most computer networks have a firewall, which controls access. A firewall is perhaps the first line of defence in preventing unauthorised access, as it can screen and filter traffic attempting to get on to the network.
All traffic attempting to gain access to the network has to pass through the firewall; however, not all unauthorised attempts to gain access to a network is from people, malicious software is often used to gain access to data or disrupt a compute network, and often these programs can get past this first line of defence.
Different forms of malicious software can gain access to computer networks, and include:
- Computer Viruses and Worms
These can change or replicate existing files and programs. Computer viruses and worms often steal data and send it to unauthorised users.
Trojans appear as harmless software but contains viruses or other malicious software hidden in the program and are often downloaded by people thinking they are normal and benign programs.
Computer programs that spy on the network, reporting to unauthorised users. Often spyware can run undetected for a long time.
A botnet is a collection of computers taken over and used to perform malicious tasks. A computer network can fall victim to a botnet or unwillingly become part of one.
Computer networks are attacked in other ways too, such as bombarding the network with access requests. These targeted attacks, called denial-of-service attacks (DDoS attack), can prevent normal use as the network slows down as it tries to deal with all attempts at access.
Protecting Against Threats
Besides the firewall, antivirus software forms the next line of defence against malicious programs. Designed to detect these types of threats, these programs remove or quarantine malicious software before they can do damage to the network.
Antivirus software is essential for any business network and needs regular updating to make sure the program is familiar with all the latest types of threats.
Another essential method for ensuring security is to establish accurate synchronisation of the network. Making sure all machines are running the exact same time will prevent malicious software and users from taking advantage of time lapses. Synchronising to a NTP server (Network Time Protocol) is a common method of ensuring synchronised time. While many NTP servers exist online, these are not very secure as malicious software can hijack the time signal and enter the computer firewall via the NTP port.
Furthermore, online NTP servers can also be attacked leading to the incorrect time being sent to computer networks that access the time from them. A more secure method of getting precise time is to use a dedicated NTP server that works externally to the computer network and receives the time from a GPS (Global Positioning System) source.
June 21 marks the summer solstice for 2011. The summer solstice is when the Earth’s axis is most inclined to the sun, providing the most amount of sunshine for any day of the year. Often known as Midsummer’s day, marking the exact middle of the summer, periods of daylight get shorter following the solstice.
For the ancients, the summer solstice was an important event. Knowing when the shortest and longest days of the year were important to enable early agricultural civilisations to establish when to plant and harvest crops.
Indeed, the ancient monument of Stonehenge, in Salisbury, Great Britain, is thought to have been erected to calculate such events, and is still a major tourist attraction during the solstice when people travel from all over the country to celebrate the event at the ancient site.
Stonehenge is, therefore, one of the oldest forms of timekeeping on Earth, dating back to 3100BC. While nobody knows exactly how the monument was built, the giant stones were thought to have been transported from miles away—a mammoth task considering the wheel hadn’t even been invented back then.
The building of Stonehenge shows that timekeeping was as important to the ancients as it is to us today. The need for acknowledging when the solstice occurred is perhaps the earliest example of synchronisation.
Stonehenge probably used the setting and rising of the sun to tell the time. Sundials also used the sun to tell the time way before the invention of clocks, but we have come a long way from using such primitive methods in our timekeeping now.
Mechanical clocks came first, and then electronic clocks which were many times more accurate; however, when atomic clocks were developed in the 1950’s, timekeeping became so accurate that even the Earth’s rotation couldn’t keep up and an entirely new timescale, UTC (Coordinated Universal Time) was developed that accounted for discrepancies in the Earth’s spin by having leap seconds added.
Today, if you wish to synchronise to an atomic clock, you need to hook up to a NTP server which will receive an UTC time source from GPS or a radio signal and allow you to synchronise computer networks to maintain 100% accuracy and reliability.
The Pacific Island of Samoa, once the last place on Earth to see the sunset, is to move the entire nation into the future by 24 hours!
Of course, the Samoans haven’t discovered the secrets to time travel, but are skipping an entire day to make their nation fall on the other side of the International Date Line (IDL).
The International Date Line (IDL) the imaginary longitudinal line on the surface of the Earth where the date changes as a ship or aeroplane travels east or west across it. Since 1892, Samoa has sat on the eastern side of the IDL, but now the country’s Prime Minsister, Tuilaepa Sailele Malielegaoi intends shifting the nation to the western side, in essence skipping a day, making trade with neighbouring Australia and New Zealand easier.
When the change goes ahead at the end of the year, Samoa’s population of 180,000 will lose a day, going from 29 December straight to 31 December (The 30 December was chosen so presumably Samoan’s can still celebrate New Year’s Eve).
Samoa isn’t the only country to jump forward in time. When changing from the Julian calendar to the Gregorian in 1752, the British Empire had to skip 11 days, while Russia, the last European country to adopt the Gregorian calendar, had to skip 13 days (interestingly this makes the anniversary of the October Revolution fall on 7 November).
Difficulties with Time Zones
While Samoa’s difficult with trade has necessitated this change, a global economy means that a universal time system is necessary for communication between countries in different time zones.
UTC-Coordinated Universal Time was set-up for just this purpose. Governed by atomic clocks, the world’s most accurate timepieces, UTC allows the entire world to be synchronised to the exact same time.
UTC is often used by technologies such as computer networks to allow communication across the globe, preventing errors and miscommunication. Most technologies utilise NTP servers (Network Time Protocol) to receive a source of UTC time—either from the internet, GPS signals or radio frequencies—and distributes it around the computer network to ensure every device is synchronised to the same time.