Draft CIS-532Abstract In this article, we first describe the definition of Cloud Computing and then its variants. We will discuss in the following discussion about the early needs of the cloud and the advantages and disadvantages of cloud computing. Obviously, Cloud Computing is a virtual computing and storage power that is delivered through the platform-agnostic platform of hardware and software that access the Internet. These shared resources are effectively created and distributed in a variety of waysThe cloud can be private or public. The public cloud sells services to anyone on the Internet.Cloud Computing offers the following services: i-Infrastructure as a Service (IaaS) ii-Platform as a Service (PaaS) and Software as a Service (SaaS).Keywords: Cloud Computing, Virtual Server, LaaS, Paps, SaaS.1- DefinitionsCloud computing is a general term for anything that involves hosting services hosted on the Internet. These services are widely distributed: the infrastructure as a service (IaaS), Platform-as-a-Service (PaaS) as a service (SaaS). When a public cloud service provider creates his own private cloud, the result is a virtual private cloud. Private or public aims to provide easy access to information technology services. To start, stop, access and configure virtual servers and store them.The platform is defined as a service in the cloud as a set of software development tools and a host product in the infrastructure of the providers. Developers create applications on the platform of providers on the Internet. Paas providers may use APIs, website portals or gateway software installed on client computers. In the supercomputer model as a service, the supplier of hardware infrastructure provides software products and communicates through a front-end port.These services are divided into three categories: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).2- Different Types of Cloud Computing:Public Cloud: Computing infrastructure is hosted on the vendor’s premises. The customer has no visibility over the location of the cloud computing infrastructure. Private Cloud: Computing architecture is dedicated to the customer. They are expensive and secure than Public Clouds. Hybrid Cloud: Organizations host some critical, secure applications in private clouds.The not so critical applications are hosted in the public cloud.Community Cloud: The cloud infrastructure is shared among the organizations of the same community.3-LayersOnce an internet protocol connection is established among several computers, it is possible to share services with anyone of the following layers.a-ClientA cloud client consists of computer hardware and/or computer software that relies on cloud computing for application delivery and that is, in essence, useless without it.b-ApplicationCloud application services or “Softwares as a Service (SaaS)” deliver software as a service over the Internet, eliminating the need to install and run the application on the customers own computers and simplifying.c-Platform Cloud platform services, also known as platform as a service (PaaS), deliver a computing platform, often consuming cloud infrastructure and sustaining cloud applications. It facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers.Cloud computing is becoming a major change in our industry, and one of the most important parts of this change is the shift of cloud platforms. Platforms let developers write certain applications that can run in the cloud, or even use services provided by the cloud. When development teams create applications for the cloud, they must build its own cloud platform.d-InfrastructureCloud infrastructure services, also known as “infrastructure as a service”(IaaS), deliver computer infrastructure a platform virtualization environment as a service, along with storage and networking and servers, software, data-center space.The servers layer consists of computer hardware and computer software products that are designed for the delivery of cloud services, including multi-core processors, cloud-specific operating systems, and combined offerings. 4- Advantages and Disadvantages of Cloud Computing in a General: • Lower computer costs: You do not need a high-powered and high-priced computer to run cloud computing web-based applications.• Improved performance: Cloud computing system boot and run faster because they have fewer programs and processes loaded into memory…• Reduced software costs: Instead of purchasing expensive software applications, you can get most of them for free in the cloud.which alone may be justification for switching to cloud applications• Instant software updates:Another advantage of cloud computing is that you are no longer faced with choosing between obsolete software and high upgrade costs.When the application is web-based, updates happen automatically -available the next time you log into the cloud.• Document format compatibility.You do not have to worry about the documents you create on your machine being compatible with other users applications or operating systems. There are potentially no format incompatibilities when everyone is sharing documents and applications in the cloud• Unlimited storage capacity: Cloud computing offers virtually limitless storage. Your computers current200 Gbyte hard drive is small compared to the hundreds of Bytes available in the cloud. Whatever you need to store, you can.• Increased data reliability: Unlike desktop computing, in which if a hard disk crashes and destroy all your valuable data, a computer crashing in the cloud should not affect the storage of your data. That also means that if your personal computer crashes, all your data is still out there in the cloud, still accessible.• Universal document access: That is not a problem with cloud computing because you do not take your documents with you Instead, they stay in the cloud, and you can access them whenever you have a computer and an Internet connection.All your documents are instantly available from wherever you are.• Latest version availability: Another advantage of cloud computing is that when you edit a document at home, that edited version is what you see when you access the document at work.The cloud always hosts the latest version of your documents.• Group collaboration: Many users do this as it is an important advantage of cloud computing -multiple users can collaborate easily on documents and projects. The documents are hosted in the cloud, not on individual computers, all you need is an Internet connection, and you are collaborating. Device independence: You are no longer tethered to a single computer or network. Changes to computers, applications, and documents follow you through the cloud. Move to a portable device, and your applications and documents are still available.Disadvantages of Cloud Computing• Requires a constant Internet connection, without internet cloud computing is impossible. If you do not have an Internet connection you cannot access anything, even your own documents. Work in areas where Internet connections are few or unreliable, a cloud could be a deal-breaker.• Can be slow:Even with a fast connection, web-based-applications can sometimes be slower than accessing a similar software program on desktop PC.Everything about the program, from the interface to the current document, has to be sent back and forth from your computer to the computers in the cloud. If the cloud servers happen to be backed up at that moment, or if the Internet is having a slow day.• Features might be limited:Today many web-based applications are not as full-featured as their desktop-based applications. The basics are similar, but the cloud application lacks many of advanced features. • General Concerns:Each cloud systems use different protocols and different APIs… so it may not be possible to run applications between cloud-based systems.Advantages and Disadvantages According to LayersSaaS :Advantages: Free and Easy Consumer Adoption, Good for developers, more control than Application Clouds, Full control of environments and infrastructure, configured, Extends functionality of Computer & Storage Clouds to integrate with legacy system or other clouds, Provides more options for Cloud EnvironmentsDisadvantages: Limited functionality, no control or access to underlying technology, restricted to what is available, other dependencies to Infrastructure provide computer and Storage clouds Virtualization layers.Infrastructure and platforms with basic functionality Sometimes requires uses specific platforms or infrastructure for management, dependent on Cloud providers6-CONCLUSION:Finally, cloud apps don’t eat up your valuable IT resources, so your CFO will love it. This lets you focus on deploying more apps, new projects, and innovation.Cloud computing is a simple idea, but it can have a huge impact on your business.