Cloud Computing

Hi Friends

Today I will be discussing about "Cloud Computing" which is becoming very popular these days.

Cloud computing is Internet ("cloud") based development and use of computer technology. It is a style of computing in which dynamically scalable and often virtualised resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure "in the cloud" that supports them.

The concept incorporates infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS) as well as Web 2.0 which have the common theme of reliance on the Internet for satisfying the computing needs of the users.

The term cloud is used as a metaphor for the Internet, based on how the Internet is depicted in computer network diagrams, and is an abstraction for the complex infrastructure.



Architecture

The majority of cloud computing infrastructure as of 2009[update] consists of reliable services delivered through data centers and built on servers with different levels of virtualization technologies. The Cloud appears as a single point of access for all the computing needs of consumers.

Characterstics

- Cost is greatly reduced and capital expenditure is converted to operational expenditure
- Device and location independence enable users to access systems using a web browser regardless of their location or what device they are using.
- Reliability improves through the use of multiple redundant sites, which makes it suitable for business continuity and disaster recovery.
- Scalability via dynamic ("on-demand") provisioning of resources
- Security typically improves due to centralization of data
- Utilisation and efficiency improvement

Types of Cloud Computing



Public cloud

Public cloud or external cloud describes cloud computing whereby resources are dynamically provisioned on a self-service basis over the Internet, via web applications/web services.

Hybrid cloud

A hybrid cloud environment consisting of multiple internal and/or external providers "will be typical for most enterprises".

Private cloud

Private cloud is cloud computing on private networks. It capitalising on data security, corporate governance, and reliability concerns.

Using Cloud computing users can avoid capital expenditure (CapEx) on hardware, software and services, rather paying a provider only for what they use. Consumption is billed on a utility (e.g. resources consumed, like electricity) with little or no upfront cost. Other benefits of this time sharing style approach are low barriers to entry, shared infrastructure and costs, low management overhead and immediate access to a broad range of applications.

As customers generally do not own the infrastructure, they merely access or rent, and consume resources as a service, paying instead for what they use. Many cloud-computing offerings have adopted the utility computing model, which improves utilization rates, as servers are not left idle, which can reduce costs.

I will be discussing the implementation of cloud computing in my coming interactions.

Happy Learning !!...

Cheers

Madhu S

Write to me at madhusudan81@gmail.com

Virtualization - The Next Big Technology in 2009

Hi Friends

Today Virtualization is the most talked about technology in the market. Today, I will be discussing some aspects of Virtualization.

What is Virtualization?

Virtualization is the simulation of one or more server environments on an actual server. It is a technology that is rapidly transforming the IT landscape and fundamentally changing the way that people compute.

Today’s powerful x86 computer hardware was designed to run a single operating system and a single application. This leaves most machines vastly underutilized. Virtualization lets you run multiple virtual machines on a single physical machine, sharing the resources of that single computer across multiple environments. Different virtual machines can run different operating systems and multiple applications on the same physical computer.

In its most technically advanced form the virtualization software called the hypervisor creates a layer of abstraction between the virtual servers and the native hardware. The hypervisor can run several virtual instances of multiple operating systems at the same time and the virtual servers need not be aware they are running in a virtualized environment.

How Does Virtualization Work?



The virtualization platform is built on a business-ready architecture. Use free software such as VMware (Microsoft)/VirtualBox (Sun Microsystems) to transform or “virtualize” the hardware resources like CPU, RAM, hard disk and network controller—to create a fully functional virtual machine that can run its own operating system and applications just like a “real” computer.

Each virtual machine contains a complete system, eliminating potential conflicts.

Virtual Box/VMware virtualization works by inserting a thin layer of software directly on the computer hardware or on a host operating system.

This contains a virtual machine monitor or “hypervisor” that allocates hardware resources dynamically and transparently.

Multiple operating systems run concurrently on a single physical computer and share hardware resources with each other.

By encapsulating an entire machine, including CPU, memory, operating system, and network devices, a virtual machine is completely compatible with all standard operating systems, applications, and device drivers.

Benefits of Virtualization?

The virtualization technology helps the organizations in the following ways:

- Optimum utilization of hardware resources.
- Performance.
- Low maintainance cost.
- Consolidation of hardware.

I will be discussing the implementation of virtualization in my coming interactions.

Cheers

Madhu S

contact me at madhusudan81@gmail.com

Sun - Java

Hi All

I was not in touch with all of you for a long time because i was preparing for Imagine Cup (The world's premiere student technology competition from Microsoft) whose finals will be held at Egypt.

There are competition categories from Software Design, Game Development, IT Challenge, Design, Photoraphy and many more...
I am sure all of you have registered for the same. If not then immediately visit http://imaginecup.com/ We might meet at Egypt for the finals.

Today I will be discussing some important questions about Java which might help you during your Job interview.

Q. What are the three OOPS principles?
Ans: Encapsulation, Inheritance and Polymorphism are the three OOPS Principles.
- Encapsulation: It is the Mechanism that binds together code and the data it manipulates, and keeps both safe from outside interference and misuse.
- Inheritance: It is the process by which one object acquires the properties of another object.
- Polymorphism: It is a feature that allows one interface to be used for a general class of actions.

Q. What are the advantages of inheritance?
Ans: Reusability of code and accessibility of variables and methods of the superclass by subclasses.

Q. What is meant by variable? What are the kinds of variables in Java?
Ans: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared. Java has three kinds of variables namely, the instance variable, the local variable and the class variable.

Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method. Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.

Q. What is mean by Garbage Collection?
Ans: When an object is no longer referred to by any variable, Java automatically reclaims memory used by that object. This is known as garbage collection.

Q. What is interface? What is use of interface?
Ans: It is similar to class which may contain method’s signature only but not bodies. Methods declared in interface are abstract methods. We can implement many interfaces on a class which support the multiple inheritance.

Q. Can we define a variable in an interface ?and what type it should be ?
Ans: Yes we can define a variable in an interface. They are implicitly final and static.

I will covering some more important Q&A in my coming interactions.

Happy Learning!!...

Cheers

Padhaku Einstein
Contact me at einstein.padhaku@gmail.com