Define cloud. Describe the evolution of cloud. Mention the advantages of using cloud computing.

 Cloud

The “cloud” in cloud computing can be defined as the set of hardware, networks, storage, services, and interfaces that combine to deliver aspects of computing as a service. Cloud services include the delivery of software, infrastructure, and storage over the Internet. A cloud service is any service made available to users on demand via the Internet from a cloud computing provider's servers as opposed to being provided from a company's own premises servers explained before, the most common cloud service is that one offers data storage disks and virtual servers, i.e. infrastructure. Examples of Infrastructure-as-a-Service (IaaS) companies are Amazon, Rackspace, and Flexi scale. Cloud computing is the use of computing resources (hardware and software) that are delivered as a service over a network (typically the Internet). 

Cloud computing is the on-demand availability of computer system resources, especially data storage (cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over multiple locations, each location being a data center. Cloud computing relies on sharing of resources to achieve coherence and typically uses a "pay-as-you-go" model which can help in reducing capital expenses but may also lead to unexpected operating expenses for unaware users.

The evolution of cloud are described below:-

1960’s

One of the renowned names in Computer Science, John McCarthy, enabled enterprises to use expensive mainframes and introduced the whole concept of time-sharing. This turned out to be a huge contribution to the pioneering of the Cloud computing concept and the establishment of the Internet.

1969

With the vision to interconnect the global space, J.C.R. Licklider introduced the concepts of “Galactic Network” and “Intergalactic Computer Network” and also developed Advanced Research Projects Agency Network- ARPANET.

1970

By this era, it was possible to run multiple Operating Systems in an isolated environment.

1997

Prof. Ramnath Chellappa introduced the concept of “Cloud Computing” in Dallas.

1999

Salesforce.com started the whole concept of enterprise applications through the medium of simple websites. Along with that, the services firm also covered the way to help experts deliver applications via the Internet.

2003

The Virtual Machine Monitor (VMM), which allows the running of multiple virtual guest operating systems on a single device, paved the way ahead for other huge inventions.

2006

Amazon also started expanding in cloud services. From EC2 to Simple Storage Service S3, they introduced a pay-as-you-go model, which has become a standard practice even today.

2013

With IaaS, (Infrastructure-as-a-Service), the Worldwide Public Cloud Services Market totaled £78bn, which turned out to be the fastest-growing market service of that year.

The evolution of cloud computing can be bifurcated into three basic phases:

The Idea Phase- This phase was incepted in the early 1960s with the emergence of utility and grid computing and lasted till the pre-internet bubble era. Joseph Carl Robnett Licklider was the founder of cloud computing.

The Pre-cloud Phase- The pre-cloud phase originated in 1999 and extended to 2006. In this phase, the internet is the mechanism to provide Application as Service.

The Cloud Phase- The much talked about real cloud phase started in the year 2007 when the classification of IaaS, PaaS, and SaaS development got formalized. The history of cloud computing has witnessed some very interesting breakthroughs launched by some of the leading computer/web organizations in the world.

Advantages of cloud computing

 Cloud computing offers numerous advantages both to end-users and businesses of all sizes. The obvious huge advantage is that we no more have to support the infrastructure or have the knowledge necessary to develop and maintain the infrastructure, development environment, or application, as were things up until recently. The burden has been lifted and someone else is taking care of all that. Businesses are now able to focus on their core business by outsourcing all the hassle of IT infrastructure. Some of the most important advantages of cloud computing are discussed here. Those will include both a company's and an end user's perspectives.

1. Cost efficiency. 

This is the biggest advantage of cloud computing, achieved by the elimination of the investment in stand-alone software or servers. By leveraging the cloud's capabilities, companies can save on licensing fees and at the same time eliminate overhead charges such as the cost of data storage, software updates, management, etc. The cloud is in general available at much cheaper rates than traditional approaches and can significantly lower the overall IT expenses. At the same time, convenient and scalable charging models have emerged (such as one-time payment and pay-as-you-go), making the cloud even more attractive.

2. Convenience and continuous availability. 

Public clouds offer services that are available wherever the end-user might be located. This approach enables easy access to information and accommodates the needs of users in different time zones and geographic locations. As a side benefit, collaboration booms since it is now easier than ever to access, view, and modify shared documents and files.

3. Increased storage capacity.

 The cloud can accommodate and store much more data compared to a personal computer and in a way offers almost unlimited storage capacity. It eliminates worries about running out of storage space and at the same time it spares businesses the need to upgrade their computer hardware, further reducing the overall IT cost. 

4. Backup and recovery. 

The process of backing up and recovering data is simplified since those now reside on the cloud and not on a physical device. The various cloud providers offer reliable and flexible backup/recovery solutions. In some cases, the cloud itself is used solely as a backup repository of the data located on local computers.

5. Cloud is environmentally friendly.

 The cloud is, in general, more efficient than the typical IT infrastructure and it takes fewer resources to compute, thus saving energy. For example, when servers are not used, the infrastructure normally scales down, freeing up resources and consuming less power. At any moment, only the resources that are truly needed are consumed by the system.

6. Resiliency and redundancy. 

Cloud deployment is usually built on a robust architecture thus providing resiliency and redundancy to its users. The cloud offers automatic failover between hardware platforms out of the box, while disaster recovery services are also often included.

7. Scalability and performance. 

The cloud systems are generally quick to deploy and have ease of integration. Such systems can be up and running in a very short period, making quick deployment a key benefit. In the same aspect, the introduction of a new user in the system happens instantaneously, eliminating waiting periods.

8. Device diversity and location independence. 

Cloud computing services can be accessed via a plethora of electronic devices that can have access to the Internet. These devices include not only traditional PCs but also smartphones, tablets, etc. With the cloud, the "Bring Your Own Device" (BYOD) policy can be easily adopted, permitting employees to bring personally owned mobile Pratdevices to their workplace.