What is cloud computing?

What is cloud computing?

Refers to providing a computing environment such as file repositories, databases, virtual servers, networks, and software via the Internet.
In other words, it can be thought that it is collectively referred to as all the functions that the personal computer, including the server, can have or serve through the Internet.

To service everything on the Internet, cloud computing should have the following characteristics.

• Broad network access

Various user devices must be able to access the service through the Internet.

• On-demand and Self-service

Resources such as servers, networks, and storage must be available at the request of the user at all times and must be user-controllable.

• Resource pooling

The entire resource provided must be shared and reused by multiple users, and instead each user domain must remain independent until the resource is returned.
To do this, virtualization and multi-tenant must be implemented.

• Rapid elasticity

The resources provided should be supplied with rapid elasticity.

• Measured service

The user's service usage should be measured quantitatively and delivered to the user.



Cloud computing having the above characteristics can be classified as follows according to the service range.

Source : https://blogs.msdn.microsoft.com/eva/?p=1383

• Packaged Software

With the advent of personal computers, a model has emerged in which individuals manage their own resources, from hardware to software.
The software was packaged, and users had to install the packaged software on their computers before they could use it.
Moreover, in order to access the internet, I had to apply for Internet service to the telecommunication service provider, and if the storage capacity was insufficient, I had to do all the work to increase the capacity of the hard disk (HDD).
The user was a model that had to be professional at the computer.

• IaaS(Infrastructure as a Service)

The IaaS model of cloud computing is a model in which the infrastructure resources are provided as services and only the rest are managed by the user.
Therefore, the user does not directly select an Internet service provider or increase the capacity of a hard disk (HDD), but is provided as a service.
The user's task is to determine the speed of the Internet and the capacity of the hard disk to self-service and pay for it.
Early cloud computing developed services with the IaaS model.
At present, EC2 and S3 from Amazon (AWS), Azure and IBM from Microsoft both provide services for the IaaS model.

• PaaS(Platform as a Service)

The PaaS model extends beyond the IaaS model to O / S and middleware as a service.
The user can receive not only the hardware resource (H / W Resource) but also the O / S and the middleware running on the O / S as a service request.
Ultimately, the user is only concerned with application development and data management.
Currently, cloud computing is expanding its IaaS model service to PaaS.
Amazon (AWS), the cloud computing leader, and Microsoft's Azure all offer PaaS model services.

• SaaS(Software as a Service)

The SaaS model extends the scope of the PaaS model to provide both application and data management services.
The user's task is to develop a business model and select the services corresponding to the business model.
Current cloud computing providers are not yet fully supporting the SaaS model.



From the local computing age to the cloud computing age, the world is changing rapidly.
Cloud computing is also rapidly evolving from IaaS to PaaS.
Cloud computing will soon evolve in SaaS in PaaS.