Virtualization: Virtual Server

Virtualization is a framework or methodology of dividing the resource of a computer into multiple execution environments, by applying one or more concepts of technologies. This new virtual view of the resource is not restricted by the implementation, geographic location or the physical configuration of underlying resources.
Commonly virtualized resources include computing power and data storage.

Most important thing that comes in the virtualization is the Virtual Machine, which can be defined as a machine, completely defined and implemented in software rather than hardware. It is often referred to as a "runtime environment"; code compiled for such a machine is typically called byte code.

Virtual machine allows a single hardware platform to host multiple operating system and application, reducing the number of physical servers required while maximizing the utilization of each server.
The creation and management of virtual machine is often referred to as server virtualization.

Benefits of server virtualization is fewer wasted cycles and a reduction in processors brings power saving, management simplification, enhanced security and extreme agility to the data center.

We will take a look into real scenario of virtualization. Now days many operating systems are available in the market like: Windows XP, Windows Server 2003, Linux and so on.
If you want to choose which operating system to use among many then, either you have to install a multi-boot loader that lets you choose what OS to load during boot-up time. But that involves some experience and a little bit of skill, and partitioning hard disks is not for the faint-hearted or one more thing you can do you can use a different hard disk for each operating system and swapping the required hard disk during boot time, but this solution is really very costly.
Now the best solution for choosing one among many operating systems is virtualization.
With virtualization, you can install new operating systems as easily as installing a new game on your PC, and you can run more than one operating system at the same time.

There are many forms of virtualization some of them are listed below:
Ø Operating system-level virtualization
Ø Application Virtualization
Ø Partitioning
Ø Domaining

We will talk more about virtualization and its forms in my next article.

Router

If you have little idea about computer networks or even if you are using Internet, you must have come across the word “router”. Now the question arises what is “router” and of course what is “routing”?
We all know that in any computer network data is transported from one location to another location.This transportation of data is known as “routing”.
Internet is a worldwide network of computer networks. It is an interconnection of large and small networks around the globe. To connect one network to another we need some sort of linkage, this linkage provided by an electronic device, work of this device is to connect two or more networks and route incoming data packets to the appropriate network.
The well known term for such device is “router”.

When we send any data across the network, it flows in the form of packet, besides containing data itself these packets contains two addresses. One which is assigned to the machine sending data i.e source address and other assigned to the machine receiving data i.e destination address.The addresses which we are talking about is known as IP addresses. IP stands for internet protocol.All computers across the internet are assigned a globally unique identifier called IP address. IP addresses are used as street addresses so other computers can locate them, these addresses takes the form of four numbers separated by dots e.g 124.45.69.89. In future it will be six numbers like 192.168.222.212.10.111

Function of router is to take out the destination IP address from the packet and determines the next network point to which a data packet should be forwarded towards its destination. Before reaching the destination from source, packet may have to follow a long path, in between it may go through many routers, like first router may send it to second and so on….number may rise up to 10 to 20 routers..or even more.
When ultimately packet reaches to the destination machine, that machine uses the source IP address of the packet to send to send acknowledgment indicating that packet has arrived.
This may also happen that packet may not arrive due to some reason, in that case error will be sent to the source machine.

One more very important function played by router is acting as “firewall”. Briefly I am explaining how it does so.
When our PC is directly connected to the internet, a unique address is assigned to our PC by Internet Service Provider(ISP), we have already discussed about this address i.e IP address.For example, you are now connected to the internet, your PC will be having a globally unique IP address, this address is very public i.e it can be known to anyone anywhere on the internet. In such cases, anyone can use the IP address of user machine to do some mischievous work, for example anyone can install some software to keep track of user activities. One of the software known as spyware can be installed in user machine that covertly gathers user information through the user’s internet connection without his or her knowledge.

In such cases router can act as hardware firewall, it does not allow computer’s IP address to directly expose to the internet.

Now the question arises how it does so?
What happens in such cases the IP address is assigned to the router by ISP(Internet Service Provider) and not to the PC, now it’s the work of router to assign private address to the PC. When we send any packet, router removes the source IP address and attaches its own public IP address, in turn stores the information about all the changes which were made. When any packet comes to the PC , router gets information which it has stored and accordingly routes the packet to the source machine. In this way our PC is not visible on the net, but our PC can see the internet……….isn’t it greatJ

Data Back Up

Before reading this article, give me the answer of one question.
Would you prefer to drive car without seat belt and insurance? I hope answer is “NO”. Your life and livelihoods is more important than few bucks. But that is the kind of risk you are taking by not backing up your crucial data.
Data loss can happen in many ways, like power surges, a virus or even a thief could wipe out your data in a second. Among all, most common cause is physical failure of the media the data is stored on. You must be saving your data on your PC’s hard drive, and that hard drive will not live forever. Once the hard drive crashes, its very difficult and expensive to retrieve that data.

Nobody wants to loose few month’s worth of emails, important memories that are stored in computer, no body would like to loose those baby photographs or those poems that you have written in spare time or all the financial account data which you took so much pain to built.
If you don’t want to loose your data best and only one solution is Data backup.

Data backup involves storing of files from your computer in another location. In this way, if there is ever any loss of data on your primary machine, you still have your data in backup in order to restore those files.
In this digital world loss of data is a nightmare. Data recovery from a crashed system is very difficult, time consuming and expensive than restoring your files from backup.

Back up does not take much time, as it is easy to put your files onto another medium and is not too expensive; depending upon what medium you use to backup your data. There are many options for data backup, and you will have to choose the one that is best for you.

Even if you are backing up, you have to make sure you are doing it right, you should know the version of the software and the operating system you are using.

You can copy your files to: -
1. A floppy disk: - This is least recommended method; floppies fail rather quickly and are not reliable. Use them only for temporary storage or data transportation, if there is no other way.
Capacity of floppies are also very less. For copying a single file floppies are okay, but for all your files you would require too many floppies and it will take too much time to back up all your data. If you have a very large file then copying it across several disks can be a problem. Now days many computers no longer come with floppy disk drives.

2. High-capacity removable media, such as CD or CDRW drive or Zip drive: - These methods provide a great way to back up you files. They hold a large amount of data, for some users only one CD is require backing up whole data. Now days most computers come with CD/DVD burner and software. CDs can have files copied to them once and provide a permanent copy of your files. CDRWs (CD Rewritable) allow data to be erased and write again several times.
“Zip” is high capacity removable media format that is similar to a floppy disk—except that once zip disk stores the equivalent of at least 70 floppy disks worth of data. Like floppies, you insert a zip disk into the zip drive and it becomes accessible to your computer, you may copy data to or from the disk as you do with a floppy.

3. A USB memory key/stick/ flash drive: -these are compact memory drive that acts like a portable hard drive, letting you store and transport your most precious computer data. They hold incredibly large amounts of information and are small enough -- about the size of a pack of gum -- to slip easily into your pocket, conveniently around your neck like a necklace, or on your key chain. They come with their own software (included on the key/stick) that will allow you to password protect your files.
These should be used for temporary back up of data only.

4. Tape drive back up device: - These have been around for a long time. Tape Drive Backups allow the user to backup their data and store it remotely. They are often used for "Disaster Recovery". They can be internal to the computer or external.

There are many other methods and software which are available in market for data back up. I have mentioned most common methods of data back up.

One more important question arises: -
How often should you backup your data?

It depends on how important your data is, how much time you spent to create that data. In my views weekly backup is minimum. When you're working on projects that are especially important or time-consuming -- the next chapter of your book or dissertation, for example -- consider making a backup copy after each editing session.

For data back up you can use combination of methods. The best combination is what works optimally for you, giving you the most protection for least amount of time. All you need is a regularly scheduled routine that fits your work habits and that you can stick to. If some disaster occurs to your data, you will be glad you did backup.

GPS: Tension Free Driving

GPS stands for Global Positioning System. It is a satellite based navigation system. The GPS system utilizes satellites that have been put into orbit by the United States Department of Defense. This system help people determine their exact location i.e. exact positioning by latitude, longitude and altitude purpose can be anything like personal navigation, military activities or even to get position of your dog or your fishing boats by installing GPS respectively in dog collar or fishing boats.

Let’s take a small ride to history and know how it all started.
GPS systems all started out in the army in the year 1970, as for military purposes soldiers needed some navigation system to know their directions around other countries. Basically it was intended for military purposes only but in 1980 it was open for civilian use also. This device was very useful during the war as it saved soldier’s time and lives.

Its very interesting to know how this system works.
GPS works with 24 satellites in the orbit. The first satellite was launched in 1978 and the twenty-fourth was finally placed in 1994. This constellation of orbiting satellites that provides navigation data to military and civilian users is known as NAVSTAR.
GPS satellite orbits the earth every 12 hours (twice a day) emitting continuous navigation signals in any weather, these satellite run in a specific orbit that is about 12,000 miles above us, these satellite travel as fast as 7,000 miles an hour. With the proper equipment user can receive these signals to calculate time, location velocity. The signals are so accurate time can be figured to within a millionth of a second velocity within a few feet. Receivers have been developed for use in aircraft, ships and land vehicles as well as for hand carrying.
The GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away from the satellite it is.
Now with this distance measurement from a few more satellites the receiver can determine the user’s position and display it on the unit’s electronic map.
In order to calculate latitude and longitude position receivers receives information from three satellites, if it has to calculate altitude also then it must be able to receive information from four or more satellites. Once the user’s position has been determined, the GPS unit can calculate other information such as sunset time and other information.

When the satellites are in orbit, they are powered by solar energy, there can be chances when there is no solar energy as an eclipse, and in that case backup batteries power it. They need the energy for the rocket boosters on each satellite to keep them running in the correct orbit. At one time about 50 Watts of power or less is used to transmit information. Each satellite is built to last about 10-15 years and the US department of defense is constantly making and launching replacement satellites. Each satellite weighs about 2,000 pounds.

GPS satellites transmit signals on two carrier frequencies. The L1 carrier and L2 carrier. L1 carrier is 1575.42 MHz, is used for civilian purposes and the L2 carrier is 1227.60 MHz and is used for more precise military purposes. These signal travel by line of sight i.e. they will pass through clouds, glass and plastics but will not go through most solid objects such as buildings, mountains.
In every transmission the satellite sends three types of following informations

Pseudo-Random code- this is an I.S code that identifies which satellite the information is being sent from.
Ephemeris data-It tells the receiver where the satellite should be at any time of day.
Almanac data-It is constantly transmitted by each satellite and it contains important information about the status of satellite (healthy or unhealthy), the current date and time. The Almanac data is the part that is essential for determining the user’s position.
The GPS system has been designed to be as nearly accurate as possible. However, there are still errors. Added together, these errors can cause a deviation of +/- 50 -100 meters from the actual GPS receiver position. There are several sources for these errors, the most significant of which are discussed below:
Atmospheric Conditions also known as Ionosphere and Troposphere delays.
One source of inaccuracy is reduced speed of propagation in ionosphere and troposphere. While radio signal travel with the velocity of light in the outer space, their propagation in the ionosphere and troposphere is slower. The GPS system uses a built-in model that calculates an average amount of delay to partially correct for this type of error.
Signal Multipath.
This occurs when the GPS signal is reflected off objects such as tall building or large rock surfaces before it reaches the receiver. This increases the travel time of signal, thereby causing errors. It is difficult to completely correct multipath error, even in high precision GPS units, multipath error is a serious concern to the GPS user.
Satellite Orbits.
Although the satellites are positioned in very precise orbits, slight shifts of the orbits are possible due to gravitation forces. The resulting error is very low its not more that 2m.
Receiver Clock Errors
A receiver’s built-in clock is not as accurate as the atomic clocks onboards the GPS satellite. Therefore it may have very slight timing errors.
Satellite Geometry/shading.
This refers to the relative position of the satellite at any given time. Ideal satellite geometry exists when the satellite are located at wide angles relative to each other. Poor geometry occurs when the satellites are located in a line or in a tight grouping.
GPS technology has matured into a resource that goes far beyond its original design goals. These days scientists, sportsmen, farmers, soldiers, pilots, surveyors, hikers, delivery drivers, sailors, dispatchers, lumberjacks, fire-fighters, and people from many other walks of life are using GPS in ways that make their work more productive, safer, and sometimes even easier.
Don’t get lost while driving, for tension free and safe driving use GPS

Robots in human life

Technically robot can be define as a machine which includes various
Field of engineering and in general it can be define as the working partner of us in the field in all the situation whether it is in our house, in laboratory, in industries, in space and even for playing children.

Now the question arises do we really need robots?

Human being has some limitations regarding weather, temperature, pressure, so he is unable to work out of this limitation in those situations robots work for us, in many field like in Marines, nuclear reactor, in the deep of ocean, or to limit of space where human are helpless but robots are at work on behalf of human being.

What exactly are robots?

Robots are nothing but combination of some computational analysis, control system and actuators and some time with self-learning process called artificial intelligence. In robots generally we get data from the sensors attached to the system now according to these data control system decides at what angle and at which position unit’s motors has to move to reach the destination and then with the help of End-effectors robot performs its assigned work like search or picking and placing, opening the gate.
This is the basic of any robot, for giving additional functionality to robot some computational part should be added to it. For example in legged robot when legs are moving then special care should be taken about the center of gravity so that a balance can be introduce for both the legs and robot can walk like a human.
There are many companies and research institutes working in this field, giving us ultimate robots like Honda’s ASIMO “Humanoid robot” its like man made human being, PUMA The working hand, snake like robots (hyper redundant), wall climbing robots and many more. In addition, a very recent Ever-1 from Korean Institute for Industrial Technology is capable of showing expressions on her face, only the second android to do this after Japan’s Actroid. Another robot named T-Rot’s has fingers, which have a human-like sense of touch, so they can hold objects by adjusting their strength depending on the material.

Think about a robot as a security guard, which can monitor your house, office and take pictures of suspicious people and intruders. On the other hand, a Firefighter robot can penetrate deep into the flames and extinguish fires at their core. All these robots are already developed and in the production line.

Now days making simple robots are not a big deal, craze in this field is increasing day by day for making more complicated robots, which can do some complicated work for us.
According to one research, intelligent robot market will reach US$500 billion by 2020 as the market for “intelligent” robots holds rich potential, with countries like Japan, U.S. and many European countries racing each other for the lead.
There are many organizations like ROBOCON, TECHKRITI, which are organizing events and even competition on robotics.
In the market you will get so many games related to robots in such games there is a given task and you have to complete the task by using sensors motors and controllers.
For kids one Lego kit or Robotics invention system is available in the market by using this kit children can make their own robots i.e. own friends to play.

This is fact that robots can’t take place of a human being but this is also fact that robots are creature of human mind to make human life simpler and longer.

Here I would like to give brief description of very interesting robot i.e. snake robot.
This type of robots are used in Search Duct inspection and maintenance of Jet engine, Bomb disarming, Medical applications because of its unique features like thread like structure, enhanced mobility, Multi functionality and extra flexibility.

Now a days scientist all over the world are working hard on making complex robots for complex work, research in this field is going on the great extend.
Days are not very far when robots like R2D2 like in Star Wars movie that can think, talk and move themselves will be part of everyday life. Robotic vacuum is already available in the market and people like it. Some common tasks like when we will reach to our office they will keep everything ready for us. We simply have to go and work without taking care of opening the light, AC, windows and even for the parking of your car. Robots will be there for our service.
In the coming years robots will be developed and launched commercially for education, medical and military purposes.

Are you safe on Network?

As an user of computer you must have seen messages for alerts for viruses, worms, Trojan horses and many other related to security of your computer, or you must be getting emails even phone calls making you alert about computer security. They must be telling you so many buzzwords like “your computer is being monitored and used by somebody else, we can solve the problem by installing some software…” and so on.

Now the bottom line is this,
Should you really worry about security issue? Can someone really use your computer?
Answer is simple and straight “Yes”.

You must be thinking why anybody would like to intrude your system?
Reason can be anything like-
Ø May be someone is interested in getting your personal information or a person wants to steal some data from your system.
Ø May be some one wants to cause damage to your system.
Ø May be someone wants to test his or her computer skills?

Someone may be interested in your personal information for financial gain, may be the person is interested in your credit card number or your bank account number or even your SSN number.
Most credit card thieves are interested in cracking databases maintained by merchants, financial firms like banks and credit reporting services. How hacker can get my password or credit card information? Hacker can install some malicious code that could also track your keystrokes and send the data to remote attacker all usernames and passwords it obtained when you visited an online banking site.

A person could be interested in causing damage to your system, reason can be anything like the person is not having good relations with you, so by damaging your system he or she wants to take revenge from you for any reason.

Its not always that person who is cracking your system (crackers) is for wealth and revenge. Most crackers see the process as a game; an exiting challenge that let them uses their knowledge of computer.

There are some cases where cracker wants to break into a “secure” system to demonstrate its vulnerabilities to its owners.
Reason can be there where cracker wants to use your system for doing illegal work. They don’t want them to be traced down, so they may want to put you in all illegal activities.
If you have high-speed Internet access with wireless router then the risk of getting exposed to the hackers is more. Some of the security risks for wireless Internet access are Insertion Attacks, Interception and monitoring wireless traffic, Configuration change, and Network Jamming etc.

With so many reasons and so many cases regarding network security and so many threats coming from so many different angles, a question arises how are you supposed to protect yourself?

You cannot get 100% protection, some of the risk is impossible to avoid, you can’t control what comes from outside.

But still we can take some measures to minimize the disasters and risk of losing personal information.
Plan in advance for your system recovery. Like you should have back up for all your important data, pictures, songs etc.

Do not forget the Basics of Security
Regardless of how much protection you have in place, or whether you use a Mac, Windows XP, or Firefox browser etc, all the security precautions should be taken.

Spend some money in buying good anti virus software, hardware or software based firewall, latest intrusion detection system, anti spy ware, install them in your system and keep updating these protection software, security patches from vendors regularly, because in every new version these software’s have new features for new possibilities.

Keep changing your password regularly and most important thing, password should be unpredictable. You should not keep your name your pet’s name or any other related name or number as your password. If you are giving your password to anyone like to your computer consultant then change it immediately after your work is being done.

E-mails are the most common source of virus. Do not open any suspicious mail attachments, which comes with any mail even from your friends or relatives, it can be a program to get into your system and take out all your data. Email worms routinely spoof the sender information. Some of the recent virus file extensions are exe, inf, url, vbs, vbe, wsf, wsh, wsc, zip etc.

Disconnect your system from Internet when you don’t use it. If you are using wireless router then keep the password security or Wi-Fi Protected Access (WPA) enabled.

These are few measures, which when combined with your common sense can serve you as tools for preventing your system from outside raiding to some extent.

Voip:technology to cut your phone calls

VoIP : Technology to cut your phone call charges.

Have we ever realized, how much will be benefited by VoIP technology? Personally I am very thankful to VoIP, as I am (staying in US) far from my parents and in-laws, but I can talk to them in India for about half an hour or more (depends on them and me), without costing so much. Simply we need computer, sound card, speakers and microphone.
What is VoIP anyway? If you are new to VoIP and want to get basic understanding of how it works, how will you get benefited by VoIP solution as a customer then this article is for you.

Let’s get started.
VoIP is a technology that allows us to make phone calls over a broadband Internet connection as opposed to traditional analog phone lines. In simple terms it makes our computer or laptop as telephone.

How does VoIP works?
Before going to basics of VoIP technology, lets take a look on how our 100-year-old traditional telephone system works.
Traditional telephone system works on circuit switching, means when a call is made a connection is set up between source and destination, in both directions, and it is maintained till duration of call. This is a dual directional i.e. we are connecting two ports in both directions, so it will make a circuit.
There is one drawback in this system, i.e. the telephone line cannot distinguish between useful talking and silence. Like if conversation is going on between two persons then one will be talking and other will be silent, so half of the transmission data is wasted in this case. Apart from this, there are many instances when there is pause between conversation that silence is also treated as data and its transmission is a waste. So if we can handle these two issues that is if we can transmit only useful data and remove unwanted instances then we can cut data transmission by more then half.

VoIP technology took care of this drawback, so it uses packet switching, in this case it opens connection just long enough to send bits of useful data called packet from one system to another. This scenario is same as your computer is making connection to any website, as and when it is required, otherwise internet connection will be very slow, if it will constantly maintain connection with any web page.
This type of system allows the network to send our call (in packet) along the least congested and cheapest line available, we can say that about 3 to 4 calls from a VoIP system could fit in the space of our call from a circuit switch system.
This is the basic reason why VoIP is cheaper then conventional calling plans.

There are different types of VoIP calling some of them are mentioned below.
* ATA (Analog Telephone Adaptor) this adaptor enables us to make use of standard telephone for VoIP options, it actually allows to connect phone that is already at our home to our computer internet connection .ATA converts analog signal to digital signal, that can be easily transmitted through internet.
* The next type of calling is through IP phones; they look just like our normal phones with same buttons. This only difference is they replace old style wall jack connector with Ethernet connectors, so it gets plugged directly into the router.
* The most common type of calling is from computer-to-computer. This is the simplest and cheapest way to use VoIP. These calls are entirely free, only thing you need software that you can download from Internet, a broadband or DSL connection, microphone, speaker and sound card.
* The latest technology that is emerging in the market and gaining popularity is Wi-Fi phones. This hybrid-Phone let people make connections using a local wireless Internet access point seamlessly switch over to a cell network whenever necessary.

Other than saving money there are more benefits from using VoIP system. What all benefits you get depend on provider also, some of the benefits are listed below.
* Much cheaper long distance and international calls.
* Many features (depends on provider) like Email alert for new voicemail, web access to voicemail, auto forward, caller ID, call waiting caller ID, call forwarding etc.
* Flexibility, some explanation needed here. When we use VoIP phone service, our phone number is programmed into the converter, so we can take our converter and phone number anywhere in the world we want. As long as we have access to Internet connection we can use our phone number. We have option to choose area code for our phone number. Some providers allow us to have more then one phone number in different area codes, this means we get extra numbers that rings the same phone. These numbers are known as Virtual Phone Numbers. One advantage here is these numbers are local number to any area code; here we will be saving money. How? Suppose you go to some other city where you have many friends and family then they can call you on a local number, instead of paying for long distance charges to contact us.

There are many providers in the market with their own strength. As the technology is growing fast and incredible amount of work is dedicated to VoIP, some of the disadvantages that are associated with VoIP are going to resolve within next few years, it is expected that after some time VoIP will have widespread consumer acceptance.