Technology

Literature review
There have been many discussions that have been written on cloud computing. McEvoy and Schulze discuss the limitations that were experienced with grid computing. These authors believe that the flaws that was experienced with grid computing. One of the problems of grid computing is the fact that it exposes too much detail of the underlying implementation thus making interoperability more complex and scaling almost impossible (McEvoy,  Schulze, 2008). Instead of this being a flaw it became one feature of grid computing. When someone is looking for solution at a more abstract and higher level, that is where cloud computing becomes handy and plays a big role.

Jha, Merzky,  Fox also give a descripti9on of clouds as providing higher level abstraction through which services are delivered to the customer. It is widely agreed that the difference between the cloud and grid is the complexity of the interface through which the services are delivered to the customer and the extent to which the resources underlying are exposed. With cloud computing, the interfaces of higher-level cloud restrict the services to off-the-shelf software, which are deployed as a generic shared platform (Jha, Merzky,  Fox).

Conceptual framework
The theory that this paper will come up with is the fact that computing, with the cloud computing, is effective when centralized. This is because the entire buzz in this area of cloud goes back to centralization. The recent developments in computing shoes a very interesting fact that computing is shifting back to centralized services just the ones we had in the 20th century. We can thus say that the pendulum is swinging back to its original place. The theory behind all these is the fact that computing is going back to the old days of centralized infrastructure. It is therefore worth noting that computing is more efficient when they are centralized.  In my own view, there is the development of computing basing on virtualization. This is because virtualization has been the main pillar in the coming of cloud computing. All the concepts of cloud computing have all originated from virtualization technologies. A brief overview of virtualization shows that cloud computing is in itself a subset of cloud computing.

Berry et al (2005) indicates that the concept of virtual machines started to be in existence since 1960s the time when IBM first developed the act of concurrent and interactive access to a mainframe computer. Each individual virtual machine used to give users the simulation of the real physical machine thus giving them the services that could have been there if they were accessing the machine directly. This gave way to a good, elegant way of sharing resources and time. This also gave way to reduction of costs on the ever-soaring costs of hardware. Each of the virtual machine was fully protected so that each was a separate copy in the underlying operating system. Users could run, and execute applications concurrently without fearing the occurrence of crush in the system. This technology was therefore used to reduce the cost of acquiring new hardware and at the same time improving productivity because users could work at the same time on the same machine.
There has been the practice of this technology in storage devices whereby they have been divided into partitions. A partition is a division which is logical done on the hard disk drive to simulate the effect of two separate hard disks.

The act of virtualization in operating system is where there is the use of software to enable a piece of hardware to run more than one operating system images simultaneously. This technology got its boost from mainframes ten years ago which allowed administrators to bring to an end a waste of expensive processing power.

Virtualization software was adopted at a very fast rate than ever imagined. Even Information Technology experts embraced this technology. Virtualization has been applied in three areas of Information Technology. These areas include networking, storage and servers. Network virtualization is the method of combining the available resources in a network and by splitting the available bandwidth into several channels each of these channels is independent of each other and can be assigned to a particular server or device in real time. The main idea behind network virtualization is so that the network can be divided into different manageable parts.

Storage virtualization is the act of pooling physical storage from multiple network storage devices so that there is a simulation of a single storage on the network which can be managed centrally. This technology is what has been popularly known as storage area networks (SANs).

Server virtualization is the masking of resources that is used by the server which include the number of individual users on the servers and the processors in the servers from the server users. The main aim of server virtualization is so that the user is spared having to understand and manage the complex details of the server resources while striving to increase sharing of resources and utilizing the capacity so that it can be expanded at a later time.

The technology of virtualization can be seen as a subset of the overall trend in information technology where it includes autonomic computing which is a scenario where the environment for information technology can manage itself based on perceived activity and utility computing which is where computer processing power is a utility where clients can pay only as needed. The main aim of virtualization is so that administrative tasks are centralized and improvement of scalability and work-overload is achieved.

From this computing trend, it is clear that computing is headed in developing more and more virtual hardware so that the real hardware is not seen per se but their work and presence is tremendous. This explains the reason we have virtual partition drives in computer hardware, the presence of grid computing.

There are many papers and proceedings which discuss SaaS, cloud computing, virtualization, and grid computing. Several of the most useful references are summarized in this section. The references for both the support and conflicts of the various definitions are all included.

The have been various views about the cloud model. Some authors have argued that cloud computing model incorporates popular trends such as Web 2.0 SaaS, and DaaS. The main aim of all these revolutions is so that we may change the way we compute and shift absolutely from desktop based computing to services and resources which are hosted in the cloud.

There have been other explanations about cloud computing that gives the distinction between cloud services and cloud computing. He argues that a cloud service is any business or consumer service that is consumed and delivered over the Internet in real-time. Cloud computing on the other hand consists of a full information technology environment which consists of all the components of network products that make the delivery of cloud services a reality. This is what enables cloud services to be performed.

Another definition of cloud computing is that it is a style of computing where large and scalable information technology activities are provided as a service using Internet technologies to external customers. Cloud computing are characterized by their self-service nature where users customers acquire resources any time they wish to use these services as long they have an Internet connection and can get rid of these services when they are no longer interested in these services.

A cloud computing system is the environment where the consumption of cloud services is enables and made possible. Cloud computing is a new way where capacity is increased, capabilities added and functionalities exploited without the need to add any infrastructure to the system, train new skills or acquisition of a new software license. In this new setup, the services can be categorized into concepts depending on the needs of the consumer. These categories include Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), managed service providers (MSP), and utility computing which deals with products, services, and solutions that are consumed over the Internet real-time. The users of cloud computing do not possess any infrastructure of the system because there is no initial investment in serves or software licenses. They instead use the resources as a service and pay for the use of these resources which are supplied by the service provider. In this case, most cloud computing providers have options which feature computing items which range from lower-powered system units to units which require extensive multicore CPU systems which require more resources for their operations.

There have been discussions about grid concerning their relationships with cloud computing. Kourpas argues that grid has a set of resources which are physical in nature. Grid provides a way of accessing broad sets of resources. It also provides a way of interactions of IT resources thus giving a way of changing business requirements (Kourpas, 2006). Kourpas has come with five areas where grid computing is used more often which are discussed below

Business analytics
Design and engineering
Development and research
Government development
Enterprises

Kourpas also outlines the evolution of grid computing by showing how virtualization has been developed up to the advanced stages they are today. An important first generation of virtualization development is the logical joining of like resources (Kourpas, 2006). A second stage is bringing together resources which have different platforms like application servers, storage, database, and file systems. All these resources are singly managed by virtualization. The final stage is bringing together grids across organizational and boundaries of the company. Many technology professionals refer to this technology as cloud computing. Cloud computing is one of the latest technologies that is the buzzword in the technology sector today. Many companies are bracing themselves for the use of this technology to leverage their operations and come up with cheaper storage solutions for their businesses. Companies have gone a notch higher to set up their own clouds and thus the coming up of private clouds in companies. The following sections will look into the structure of private cloud as compared with other cloud computing systems like the public cloud and hybrid cloud. It will also look into how companies are using this technology to leverage their businesses for more profitability.
It is through the work of Foster, Kesselman, and Tuecke (2006) who gave the details of grid architecture from the perspective of the Globus Alliance. They break the architecture of the grid into three layers of which each layer provides unique functionalities. These services are offered from within the support of grid versus external grid services like P-a-a-S which is offered to external customers. The grid architecture includes the hardware resources that make up the physical layers in the architecture of the grid.

Messinger,  Piech, (2009) discusses the architectures that are available for cloud computing. According to them, there are three types of cloud computing architectures. The first is the public cloud. This gives a description of cloud computing basing on the traditional mainstream sense. In this, resources are provisioned in a dynamic way and are on a self-service fine-rained basis over the Internet. They are given to the consumers via web applications or web services, from an off-site provider and charge the use of these services on a fine-grained utility computing. Utility computing is the category of computing where consumers need not to purchase licenses and install on their on-site servers. They simply access the service they require from the off-site providers as long as they get access to Internet connection. These services are the computer applications that are normally installed and used on servers within an organization. What they do is to pay for a subscription fee which is proportional to the service used.

The second architecture, discusses by Messinger, and Piech (2009) of cloud computing is the Hybrid computing where there is a composition of multiple internal andor external providers, which is typical for most enterprises. A cloud can be a description of a local device, say a Plug computer with cloud services. It can also describe a configuration which is a combination of virtual and physical assets, for example most environments which have been virtualized require physical servers, routers, or other hardware such as a network appliance acting as a firewall.

The last architecture of cloud computing is the private cloud also known as the internal cloud. These are offerings that represent cloud computing on private networks. This type of cloud computing has been widely claimed to provide benefits like capitalizing on data security, corporate governance and reliability concerns. The disadvantage comes in the sense that consumers still have to buy, build and manage them, which defeats the reason why they shifted to cloud computing in the first place. This also does not benefit from lower-front cost of capital and has less hands-on management, which essentially makes it lack the economic model that makes cloud computing such an intriguing concept. Research has shown that cloud computing will be headed this way in few years to come.

Berry,  Djaoui et al, 2005 discusses the securities that are associated with cloud computing. They did not discuss the data that reside in the cloud.  Cloud computing has some attributes which must be assessed so that all matters of security and privacy is well tackled. The areas of data integrity, privacy of data, recovery of data, and evaluation of legal issues needs to be critically analyzed for risk to be minimized. Cloud computing providers like Google and their Apps engine, Amazon with their EC2 are providers whose computing can be defined as that with scalable IT-enabled capabilities which are delivered as a service to external clients by use of Internet technologies.

It is therefore imperative that customers must demand proper explanation of security policies and should know the measures that these providers are taking in place in order to assure their clients that they will not be exposed to security vulnerabilities in their course of their use of these services. They should also be able to identify vulnerabilities which were not anticipated at first.

The first issue to be considered when deploying cloud computing is the privileges given to users in order to access their data. Data which are stored outside the premises of an enterprise brings with the issue of security. Hoe safe is the data Who else assesses the data Data which have been outsourced bypass the controls of the personnel of the enterprise. The client should get as much information as possible about how the data is stored and how the integrity of this data is catered for. The providers should be asked specific information about their hiring of privileged administrators who will manage the data.

The second issue to be considered is the regulatory compliance. The consumers are responsible for the security and integrity of their own data even when this data is held and stored by other providers. In the case of traditional service providers, they are subjected to external audits by auditors who will normally check on the security policy of that enterprise. The cloud computing providers should accept to undergo these external audits and this should be agreed upon in written form.

The other security policy to be considered is about the location of the cloud. In most cases, consumers do not know where the cloud is located and even dont know which country it is. What they care is that their data is being stored somewhere. The providers should indicate, in written form, their jurisdiction and should accept to obey local security policies on behalf of the consumers.
Another issue is that consumers should be aware of the security breaches present with providers. Providers have always claimed that security is at its tightest in the cloud but this fact alone is not enough to assume security issues. It is good know that all security systems that have been breached were once infallible and so with newer technologies, they can be broken into. An example is Google which was attacked in 2007. Their Gmail services was attacked and had to make apologies. With this in mind, it is a good lesson to learn that even though systems might be tight in the cloud, it is not a full assurance that they will never be hacked. While providers of cloud computing face security threats, research has shown that cloud computing has become very attractive for cyber crooks. As the data become richer in the cloud, so should security become tighter