Network Time Protocol - Explaining NTP Servers and Network Time Synchronisation

NTP is almost as old as the Internet itself. It was devised and developed by Dr David Mills of the University of Delaware and has been in constant use and continually updated since 1985. NTP is an internet protocol designed to synchronise clocks on a computer network.

In a modern global economy time synchronisation is essential for carrying out time sensitive transactions such as booking an airline ticket to bidding on Ebay. If clocks were not synchronised to the same time you may find your airline seat sold after you had bought it and Ebay's administrators would not be able to discover whose bid was the latest.

NTP can synchronise networks across the Internet or a Local/Wide Area Network (LAN/WAN) it synchronises time with reference to a reliable clock source. This source could be relative such as a computer's internal clock or the time on a wrist-watch or absolute such as time from an atomic clock.

Most network administrators prefer to use an external absolute source, mainly because specialist NTP servers are available that can easily receive an atomic clock timing reference either through specialist radio transmissions (usually from national physics laboratories) or the GPS network.

A universal timescale called UTC (Coordinated Universal Time) has been developed allowing networks all around the world to be synchronized to the same timescale and supports such features as leap seconds - added to compensate for the slowing of the Earth's rotation

NTP uses an algorithm (a complex sequence of instructions) to keep time by constantly checking the time source and matching it to the time on its clocks on the network and instructs each device to alter if it becomes out of synchronisation.

NTP uses timestamps to represent the current time of the day each. As time is linear each timestamp is always greater than the previous one. NTP timestamps are in two formats but they relay the seconds from a set point in time (known as the prime epoch, set at 00:00 1 January 1900) The NTP algorithm then uses this timestamp to determine the amount to advance or retreat the system or network clock.

NTP analyses the timestamp values including the frequency of errors and the stability. A NTP server will maintain an estimate of the quality of both it's reference clocks and itself.

The NTP program (daemon on UNIX, service on Windows) runs in the background. NTP receives exchanges time information by packets (a block of data) but refuses to believe the time it is told until several exchanges have taken place, each passing a set of tests or protocol specifications. Only if the replies from a server satisfy these tests does the NTP utilizes this information. It usually takes about five minutes (five good samples) until a NTP server is accepted as a timing source.

Microsoft, who has installed a version of NTP in their operating systems since Windows 2000, strongly recommends that a hardware source is used as a timing reference as Internet sources can't be authenticated.

Authentication verifies that each timestamp has come from the intended time reference by analysing a set of agreed encryption keys that are sent along with the time information. NTP, using Message Digest encryption (MD5) to un-encrypt the key, analyses it and confirms whether it has come from the trusted time source by verifying it against a set of trusted keys.

The best solution is to use a specialist NTP server and receive an authoritative time reference via either the GPS network or radio transmissions (known as MSF in the UK or WWVB in the US).

NTP servers judge the distance of each network device from a timing source and organises them into Strata. These Stratum levels exist to prevent cycles and guarantee accuracy. Stratum 0 are devices such as reference clocks connected directly to a computer. Stratum 1 are computers attached to stratum 0 devices, while Stratum 2 are computers further out.

NTP is free to download via NTP.org and is continually supported and updated. The current version is v 4. A simplified version of NTP (SNTP) exists has less functions and is used in some devices and applications (and also included in older versions of Windows) where high accuracy timing is not as important.

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Registry Cleaners and You

Diagnosing the Brain: Your Computer's Registry

Many of us use our computers every day, unaware of the daily assaults they endure from adding and deleting files and programs or simply surfing the internet. Every action a computer does requires accessing its registry, and over time, these actions begin to affect the computer's ability to read its internal registry, which is kind of like an inventory of all the information on your computer that tells it how to run files and programs. Your computer constantly modifies that registry to account for any changes you make whether it's saving a one-page word document or doing some major programming. If enough changes are made, you may find that your computer's basic functions have been affected. It may run a little slower, display strange error messages, fail to end programs successfully, or even be unable to run at all. Many people have computer problems that are rooted in the registry, but few know what to do to remedy the problem.

Delete it, or Scrub it Clean? Fixing Computer Registry Errors

Because the registry is such a sensitive and vital part of your computer's operation, it takes a skilled technician to correctly clean it, and it can take such a specialist several hours, or even days, to inventory a whole file directory. For this reason, many people prefer to reformat the hard drive entirely, even going as far as reinstalling the operating system. Although this fix is pretty much always effective, it is very time consuming because it requires backing up all the files and programs on your computer first. Of course, it is easy to forget to back up a file, but almost impossible to get it back once the reformat is complete, so before you set out to completely wipe and reinstall your hard drive, you might want to consider other options.

While it takes the most capable computer technician much time to manually inspect and correct a registry, there are software programs that do this job automatically and in half the time. These programs, called registry cleaners, are widely available, sometimes even for free. Of course, since your registry is important and complicated enough to trust to a specialist, you want to feel secure about any program that will be combing through your computer's most vital codes and folders. Before you rush out and buy the most expensive registry scrubber you can find or download the first free application you see, there is some basic information about these programs that you should know first.

Created Equal? How to Find the Right Computer Registry Scrubber for You

To the untrained eye, there seems to be only two types of registry cleaners: those that are free and those that are not. Some people assume that officially licensed Windows programs work best and automatically purchase a registry scrubber. Others, faced with two seemingly identical programs, one of which is free, will always choose the free program. In reality, there is no correlation between price and quality. There are some equally good programs in both camps, and the only way to tell the difference is to get a sense of what people are saying about the programs and to compare the features of each choice.

Not all registry scrubbers are created equal. Some perform incomplete scans, leaving corrupted files and folders, and a few can actually damage your computer further. One way to get a sense of what a specific registry scrubber actually does is to look at its features and its ability to access and provide technical support. Each registry scrubber uses different cleaning features, including registry optimizers and compactors, AdWare and spyware removers, and deep scans. There are also features that focus on communicating with the user, such as those that offer detailed descriptions of any problems encountered or ignore lists. Comparing registry scrubber program features on a side by side basis can help you pick the application that is best for you and your PC. In general, you want the program with the most complete checklist of features, actions, and support. Keep in mind that just as there are rogue anti spyware programs out there, there are lots of rogue registry cleaners too, and those can be dangerous choices.

There are many internet sites that include side-by-side comparisons of registry cleaners, but be careful about advice from sites that advertise a particular program. More objective advice is best, especially when judging reviews. While reviews are one great way to find effective and safe registry cleaner software, they are sometimes written by representatives from the software companies themselves. Look for websites that offer a lot of different reviews about a program, and consider the overall opinion of the reviewers. Once you find a program that you like, don't be afraid to do more research on it. You can find tons of blogs, forums, and even expert opinions about specific registry cleaner software that might help influence your decision. Overall, the more information you have about a program, the more likely it is that you are making a good decision.

Although it is instinct to want to try and fix the problem as soon as possible when major computer issues occur, haste is one of the worst mistakes one can make with registry cleaners. Instead of downloading or purchasing the first registry scrubber you come across, do a little research and comparative shopping before making your decision. A little time spent finding the right registry scrubber can save you time and heartbreak later.



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Questions to Ask Before Computer Recycling

What devices can you take in for recycling?

Many of the recyclers don't accept computers from individual households, in fact they only accept devices from companies or corporations. Many only accept certain devices, not all of them. Many may just accept laptops but not printers.

What are your policies regarding data destruction?

Many computer recyclers will wipe all data several times, thereby destroying it completely. The storage media can also be physically destroyed by shredding, crushing, breaking, cutting etc.
Computer owners should back-up their data before sending outdated computers for recycling. Ensure that all storage media like hard disks have been wiped cleaned of any sensitive data.

What are the management's practices regarding computer recycling

Ask the recycler about what environmental management certification he has in place. For computer recycling, there are various certification programs such as ISO 14001 Environmental management certification and certification by organizations such as International Association of Electronics Recyclers (IAER) or the Institute of Scrap Recycling Industries (ISRI).
If the recycler isn't certified, then it's important to ask whether the company follows any recognized environmental management guideline such as EPA's Plug-in to E-Cycling Guidelines.

Have you had any safety violations or been sued for environmental damages

Check whether the company has been sued for environmental damages. Also check out any violations that it might have received in the past. Companies that have a good track record and standing should obviously be preferred.

What percentage of computer materials do you recycle?

Those companies that recycle nearly 90% of their goods are preferable to companies that recycle a lower percentage. Many things may not be recycled given the current state of technology available in the recycling industry. Look for companies that avoid landfills and safely dispose of toxic items such as mercury lamps, lead batteries etc.

How do you handle hazardous elements such as mercury lamps?

The companies that accept hazardous elements such as mercury and lead for recycling from computer components use various processes to extract these elements. They should also have written practices detailing the extraction processes of that they utilize. Hazardous elements need to be removed from laptops and computers before they are further processed.

Conclusion
Don't always go for price when choosing a recyclers. Instead, look at the environmental damage that can be caused if recycling doesn't take place. A responsible company should be able to leave the environment clean during and after computer recycling, rather than polluting it.

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The Secrets of Computer Repair

The secret to computer repair is simple: you have to know and understand how your computer system works before you try to repair a problem. Repairing a computer is like any other type of repair; you must know how each separate part works in order to make the machine run. Once you have that knowledge, many of the problems that can go wrong with computers can be solved by using your compute knowledge in order to isolate and resolve the situation.

If you want to keep your computer from having to be repaired all you have to do is be vigilant about what goes on your computer. Spyware is a big threat to many computers. It tracks your moves and can steal your information. It also reduces the overall operating efficiency of your computer. Make sure you have an anti-spyware program that will find and destroy all the spyware on your system.

Another way to prevent your computer from needing any type of repair is to reduce the number of programs in the startup menu. You do not want to try to repair a slow computer that just has too much stuff on it. Instead, you can find the programs that your never use (ones that are automatically installed by the manufacturer) and getting rid of them. This will make your computer run much faster.

The last secret to keeping your computer running smoothly and not in need of repair is to get an anti virus program and keep it updated. An anti virus program that is never updated is of little use to your computers safety. New viruses are being developed all the time and in order to keep your computer safe and secure you will have to update your anti virus software at least two or three times a week. Make sure that your settings are also correct. This will ensure that your computer is being protected from most of the common viruses.

These are probably the first three areas that a computer repair specialist will check before they begin looking for another type of problem. If you computer is slow or no running as well as it should, the most common problems have to do with the programs that you have on your startup menu, your antivirus software, and your spyware software. If none of these are lacking, and you are still having a problem with your computer, you will need to check other areas of your computer in order to isolate the problem. This is where your knowledge of all the components in your computer will help you out. Most of the time, a problem with you computer is with the software. Something doesn't work right because of a certain setting or lack of space to correct the problem and have the computer function properly. Other problems with your computer can be with the hardware.

If you want to repair the hardware inside of your computer, you will first need to use some basic safety. Do not open up your computer's unit until you have all of the power shut off. That means unplugging it from the wall. Then you can open up the case and look for your problem. There are many components inside the computer, so make sure that you know what you are looking for before you begin working to repair the problems.



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3 Reasons Your Computer Loads Slow

Why your computer loads slow can be attributed to a few reasons within the Windows operating system and because of some types of programs that clog up your memory and CPU usage that slows the computer down when loading to Windows and then when you log into Windows as well. The three main reasons why your computer loads slow are as follows:

Invasive Software
One reason your computer loads slow is that you may have some software that runs on startup that consumers and amazing amount of power leaving nothing for other programs and the user. Most often this culprit is an anti-virus checker that scans your startup and files every time you start your computer causing it to load slow. To combat this you can often disable the startup check or even disable the entire program and only use it manually if you feel secure enough as many virus checkers are overkill.

Fragmented Hard Drive
When data is moved around your computer and programs and files are deleted, installed, changed and manipulated it causes an issue called fragmentation which is when data is all over the hard disk and simply put, Windows has to spend a lot of time following references and links to all parts of the hard drive to collect all the data needed to run itself and other programs. This can cause your computer to load slow and continue to be slow when in operation as well. To fix this you can go to the System Tools in Windows which has a program called 'disk defragmenter' which finds all these fragments and sorts them in order creating a faster running hard drive. Be warned though a badly fragmented drive can take hours to defrag!

Registry Errors
One problem which is harder to fix and is a major reason your computer loads slow is that of registry errors. The registry is where Windows stores all the software and hardware instructions to run your computer, unfortunately over time errors appear often from programs not uninstalling correctly. This is harder to pick and harder to correct that the other reasons but when your computer loads slow even if the other things are fixed this will always be an invisible issue causing performance problems.

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Speed Tweaks For XP - Get Maximum Windows Performance

We would surely want to get the best out of the operating system that we have in our own computers. Sometimes, many experience a little slow down with our Windows operating system. We still haven't fully identified some of the things that could speed up our Windows XP operating system. All you need to have are some speed tweaks for XP. Once you are able to know some of these, you will have your Windows XP work to their full advantage without even budging a little. This article will offer some of the hundreds of speed tweaks for XP to give your Windows a little performance boost at every use.

Having the best out of your Windows XP system is not only about making it work faster than you want it to be. It is also being able to see the fonts clearly in your screen so you could input data faster. ClearType is one of the options provided by Microsoft in their systems in order to provide the users with a clearer and more improved appearance of text, especially when they are using LCD flat screen monitors. All you have to do is to visit the Microsoft Typography services and follow the instructions that it says. After installing the software provided in the link, you can now adjust ClearType in your Control Panel.

The Windows Media Player is another tool which we often use in our computer. Sadly, though, there are times that we haven't fully used the capability of this program to its best extent. If you are a movie buff and you would like to watch a flick while enabling the best high quality video and audio in your media player, then all you have to do is to tweak your XP to set it in an above normal priority. Just create a new textfile in your C drive, but give it with a .bat extension. Once that you've saved it, right click the file and choose Edit. Put this line in the textfile: start /AboveNormal C:\"Program Files"\"Windows Media Player"\wmplayer.exe %1 %*. Save the file and close it promptly, making sure that it has a .bat extension. Next step is to register your media files to be included in this batchfile. In Windows Explorer, go to Tools, then choose Folder Options. Go to File Types. Go to the AVI filetype and click Change. Point to the Above Normal file that you have created and click OK.

If you want to speed up the performance of your system, then you have to adjust the graphics. Sure, Windows XP boasts of a lot of state-of-the-art graphics, but this can sometimes make your system run slower. Go to the My Computer icon and click Properties. Go to the Advanced tab, and click the button under Performance, and navigate to the Visual Effects tab. Select Adjust for Best Performance. This will let your windows assume a Windows 2000 look, but nevertheless, this will speed up the performance of your operating system.

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NTP Servers - Basic NTP Configuration

Network Time Protocol has been developed to keep computers synchronized. All computers are prone to drift and accurate timing is essential for many time critical applications.

A version of NTP is installed on most versions of Windows (although a stripped down version called SNTP -Simplified NTP- is in older versions) and Linux but is free to download from NTP.org.

When synchronising a a network it is preferable to use a dedicated NTP server that receives a timing source from an atomic clock either via specialist radio transmissions or the GPS network. However, many Internet time references are available, some more reliable than others, although it must be noted Internet based time sources can't be authenticated by NTP, leaving your computer vulnerable to threats.

NTP is hierarchical and arranged into stratum. Stratum 0 is timing reference, while stratum 1 is a server connected to a stratum 0 timing source and a stratum 2 is a computer (or device) attached to a stratum 1 server.

The Basic configuration of NTP is done using the /etc/ntp.conf file you have to edit it and place the IP address of stratum 1 and stratum 2 servers. Here is an example of a basic ntp.conf file:

server xxx.yyy.zzz.aaa prefer (time server address such as time.windows.com)
server 123.123.1.0
server 122.123.1.0 stratum 3
Driftfile /etc/ntp/drift

The most basic ntp.conf file will list 2 servers, one that it wishes to synchronise too and an IP address for itself. It is good housekeeping to have more than one server for reference in case one goes down.

A server with the tag 'prefer' is used for a trusted source ensuring NTP will always use that server when possible. The IP address will be used in case of problems when NTP will synchonise with itself is. The drift file is where NTP builds a record of the system clock's drift rate and automatically adjusts for it.

NTP will adjust your system time but only slowly. NTP will await at least ten packets of information before trusting the time source. To test NTP simply change your system clock by half an hour at the end of the day and the time in the morning should be correct.

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