Cloud Computing Paper Reading Summary 2

In paper The Characteristics of Cloud Computing published by Chunye Gong etc. , these authors summarized the characteristics about cloud computing and compared Cloud Computing with High Performance Computing(HPC) and Grid Computing.

There are more than 20 definitions of cloud computing which seem to concentrate on certain aspects of this technology.
According to the provided capability type, cloud computing are divided into 3 classes:
a. Infrastructure as a Service(IaaS): delivery of huge computing resources such as the capacity of processing, storage and network. Also called Hardware as a Service(HaaS).
b. Platform as a Service(PaaS): abstracting the infrastructures and supporting a set of application program interface to cloud applications.
c. Software as a Service(SaaS): aiming at replacing the applications running on PC. A problem about SaaS is that the delay of network is fatal to real time or half real time applications such as 3D online game.

Cloud Computing is divided into 5 layers including clients, applications, platform, infrastructure and servers. 

The Cloud Computing has main characteristics like service oriented, loose coupling, strong fault tolerant, business model and ease use. As the paper authors said, the bird's eye about cloud computing or other research areas is the free encyclopedia Wikipedia.

The key characteristics of cloud computing are agility, low cost, device and location independence, multi-tenancy, high reliability, high scalability, security and sustainability. L.M. Vaquero etc. list up to 22 definitions and analyse characteristics of Cloud Computing. They pointed out that the clouds are a large pool of virtualized resources which are ease to use and access. Ten in their summary: user-friendliness, virtualization, Internet centric, variety of resources, automatic adaptation, scalability, resource optimization, pay-per-use, service SLAs(Service-Level-Agreements) and infrastructure SLAs.

Compared with HPC, Cloud Computing balanced powerful processing performance and low delay very well. Moreover, HPC is tight coupling, has too much data dependence or global among computing nodes. 

Since abstraction and accessibility are two keys to achieve the service oriented conception. Abstraction reduces both the need for cloud user to learn the detail of cloud architecture and threshold of application development.

With virtualization or other technologies, the infrastructures are separated in logic or physic, they will not affect each other. Whole Cloud Computing runs in a client-server model.

There are mainly four places where faults maybe occur in Cloud Computing: provider-inner, provider-across, provider-user and user-across.

When it comes to User Experience, it belongs to the subject of human computer interaction, which is an important criterion when evaluating whether an application is successful or not.
Cloud Computing performs better than Grid Computing in User Experience for 3 reasons:
a. Most cloud providers offer Internet-based interfaces which are simpler than other application program interfaces(API).
b. User Experience of web application is full studied so that the User Experience are independent from content.
c. The Web 2.0 increases the interactions between web users and providers.

Furthermore, Cloud Computing has characteristics such as TCP/IP based, virtualization and high security. They are all significant because TCP/IP provides reliable delivery, a connection-oriented service between remote applications. Cloud resources are often virtualized as a service over the Internet. High security relies on 3 factors: loose coupling; abstraction, virtualization, privation of cloud provider; technology cooperating with law.

In sum, the conceptional service oriented characteristic abstracts the details of Cloud Computing implementation. The loose coupling and strong fault tolerant stand for the main technical characteristics. Owing business model is the key differentiation compared with other academic researches and helps Cloud Computing flourishing. The ease use user experience helps Cloud Computing being accepted widely by non computer experts.