What is Cloud computing?

Cloud computing is not a new technology, but a new model to deliver IT resources. It gives the illusion that people can have access to an infinite amount of computing resources available on demand. With Cloud computing, you can rent computing power with no commitment. There is no need to buy a server, just pay for what you use. This new model is often compared with how people use and pay for utilities. For example, you only pay for how much water or electricity you consume for a given amount of time.

Cloud computing has drastically altered the way computing resources are obtained, allowing almost everybody, from one-man companies, large enterprises to governments work on projects that could not have been possible before.

While in the traditional IT model you need to request budget to acquire hardware, and invest a large amount of money upfront; with the Cloud computing model, your expenses are considered operating expenses to run your business; you pay on demand a small amount per hour for the same resources.

In the traditional IT model, requesting budget, procuring the hardware and software, installing it on a lab or data center, and configuring the software can take a long time. On average we could say a project could take 120 days or more to get started. With Cloud computing, you can have a working and configured system in less than 2 hours!

In the traditional IT model companies need to plan for peak capacity. For example if your company's future workload requires 3 servers for 25 days of the month, but needs 2 more servers to handle the workload of the last 5 days of the month then the company needs to purchase 5 servers, not 3. In the Cloud computing model, the same company could just invest on the 3 servers, and rent 2 more servers for the last 5 days of the month.

Characteristics of the Cloud

Cloud Computing is based on three simple characteristics:

Standardization.

Standardization provides the ability to build a large set of homogeneous IT resources mostly from inexpensive components. Standardization is the opposite of customization.

Virtualization

Virtualization provides a method for partitioning the large pool of IT resources and allocating them on demand. After use, the resources can be returned to the pool for others to reuse.

Automation

Automation allows users on the Cloud to have control on the resources they provision without having to wait for administrator to handle their requests. This is important in a large Cloud environment.

If you think about it, you probably have used some sort of Cloud service in the past. Facebook, Yahoo, and Gmail, for example, deliver services that are standardized, virtual and automated. You can create an account and start using their services right away.

Characteristics of Computers

Useful characteristics of computers
1. Speed :
The computer present in the modern world has the speed of nano and pico second. The various speed that are used by the computers from the former generations are as follows:

1 milli second=1*10^-3 second
1 micro second=1*10^-6 second
1 nano second=1*10^-9 second
1 pico second=1*10^-12 second
2. Accuracy: The accuracy of computers is quite high. They are reliable and robust. It ever makes a mistake. Most probably the error occurs due to the user rather than the computer. There may be certain hardware mistake but with the advanced technique in hand they are overcome.
Example:Only accurate robots are used to perform the operations for the patients since human hands are not flexible for making operations.

3. Diligence: Unlike human beings, computers are persistent and are not afflicted by tiredness, monotony, lack of concentration, etc.
If there are surplus amount of executions to be made then each and every execution will be executed at the same time period. They can perform their assigned task without taking any refreshment.

Example: Computers which are used for controlling the satellites.
4. Reliability: Computers produce reliable and precise results. Humans cannot work with such precision. The computers are automatic. It may execute the process without any intervention of user once they are assigned to a work. Once the data or instruction are fetched from the secondary devices such as optical disks, hard disks etc. Immediately they get stored into RAM (primary memory) and then sequentially they get executed.

5. Versatility: Computers can work with different types of data like sound, graphics, audio, etc. In our day to day life computers has been a part, with their extended flexibility they are used, all over the world. They can be used as personal computers, for home uses, for business oriented tasks, weather forecasting, space explorations, teaching, railways, banking, medicine etc. All Modern computer can perform different kind of tasks simultaneously.

6. Memory: Computers can store large amounts of data for years till a hardware failure occurs.
Secondary storage devices are the key for the data storage. They store the data for which the user wants to retrieve these data for future use. The examples for various secondary devices are Floppy disk, Optical disks (CS and DVD), Zip drives, Thumb drives etc. The data of smaller size can be easily fetched and they can be copied to the primary memory (RAM).

Example: Data Warehousing made by IBM.

Computers today have the following limitations:
1. No IQ : Computers possess no intelligence of their own. They do what they are instructed to do. They do not have brains and hence cannot think.
2. No feelings: Since computers cannot think, they also do not have any feeling.

Destructors

Whenever an object goes out of scope, it is destroyed. The memory used by that object is reclaimed. Just before the object is destroyed, an object's destructor is called to allow any clean-up to be performed.
A dectructor, as the name suggests, is used to destroy the objects that have been created by a constructor. Like a constructor, the destructor is a member function whose name is the same as the class name but is preceded by a tilde sign(~). For example, the destructor for the class number can be defined as shown below:
~number() { }
A destructor does not take any arguments; LEARN MORE>>

Constructors

C++ provides mechanisms for ensuring that your objects are initialized properly before they are used. As your objects go in and out of scope, memory is first allotted to them and then initialized. C++ provides a special member function called the constructor for the initialization of an object.
A constructor function is called whenever an object is created. An object can be created as a global variable, as a local variable, through the explicit use of the new operator, though an explicit call of a constructor or as a temporary object. Constructors are called when an object is created as part of another object. LEARN MORE>>