2. Chapter Two: Literature Review
To better understand what readiness factors for different types of cloud computing are and how to measure them, the literature review focuses on two parts.
The first part consists of the introduction of cloud computing and features of cloud computing. The second part reviews the literature relating to the readiness of cloud computing.
2.1 Cloud computing
2.1.1 Introduction of Cloud Computing
Cloud computing has become a prominent battleground among major IT vendors because there is an increasingly pervasive trend where IT vendors make most of their products online – whether it be hardware, software or network infrastructure (Hunter, 2009). As a matter of fact, cloud implementation is now a business imperative. In addition to virtualized technology, cloud computing is the culmination of several years of technology innovations and on-demand access to a shared pool of virtual computing resources stemming from years of technological development (Goodburn and Hill, 2010).
On the whole, cloud computing may be considered as having four layers of structure and three types of applications. In many cases, organizations will put one or more service structures and types of application into practice (IBM, 2010). According to Mell and Grance (2010), the common cloud service structures are as follows:
(1) IaaS (Infrastructure as a Service)
This structure consists of the use of the most fundamental computing structures, which is often rendered by cloud providers. The capability provided to the consumer is provision processing, storage, networks, and other fundamental computing resources, and the consumer is able to deploy and run arbitrary software.
(2) PaaS (Platform as a Service)
PaaS is based on IaaS. The capability provided by PaaS is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the IaaS layer.
(3) SaaS (Software as a Service)
SaaS, the most accessible layer, provides users with the cloud providers’
applications running on a cloud infrastructure. The services offered by providers are accessible from various client devices via the Internet. Consumers do not manage or control the underlying cloud infrastructure, including the network, servers, operating systems, and storage.
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clouds, each defined by the relationship between cloud providers and cloud users. The most common three types of application are as follows (Harris, 2011)
(1) Private Cloud
Private clouds are often owned and operated exclusively by one corporation.
With all their infrastructure and structure built behind an organization’s firewall, these clouds provide services for the organization’s employees and sometimes users outside the scope of the organization.
(2) Public cloud
Public clouds often refer to computing and IT infrastructure that is owned by an organization but that provides computing and information services to external users or subscribers.
(3) Hybrid cloud
These clouds are a mixture of public clouds and private clouds. They may be useful for some well-established corporations that already have their own computing and IT infrastructure but require additional computing and IT services or vice-versa.
However, this study focuses solely on the readiness for public and private clouds.
We define companies that self-own the IaaS layer of cloud computing as private cloud users even if these companies outsource the rest of the three layers to other cloud providers.
2.1.2 Features of Cloud Computing
Considering the convenience and benefits brought by cloud computing, companies are leaning toward adopting it. However, to what extent may a company be considered a fully cloud-adopting one? The answer varies according to their initial goals and purposes (Reynolds and Bess, 2009). Generally speaking, the adoption of innovations consists of a sequence of stages in which an individual or decision-making unit gains initial knowledge about an innovation, forms an attitude toward the innovation, and makes a decision to adopt or reject it (Rogers, 2003). As the adoption sequence proceeds, it will be gradual as the organization obtains a better understanding about cloud computing and as cloud computing technologies become more mature, which result in more benefits gained from cloud computing (Simalango, Kang, and Oh, 2010).
On the whole, companies must know the features of cloud computing before adoption (Emerson, 2010). We summarize the characteristics in the following table.
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Table 2-1. Features of Cloud Computing
Public CloudName Year Description Features of
Cloud Goodburn and Hill 2010 The cloud has proven itself an
effective tactic for achieving greater efficiency in applications ranging from email to photo storage to Web
2012 Public clouds are always provided by outside providers to organizations requiring them.
Third-party outsourcing Won Kim et al. 2009 A third-party computing provider
helps an enterprise store data and shares them with other enterprises.
Third-party outsourcing Knorr and Gruman 2008 The public type of cloud computing
delivers a single application through the browser to thousands of customers using a multitenant architecture.
Accessibility
Hayes 2008 The scalability of cloud computing marshals resources in a way that makes programs run smoothly even with a large number of users.
Scalability
Sudipto Das et al. 2010 Cloud computing has emerged as a pervasive platform for deploying scalable and highly available Internet applications.
Scalability
Bhardwaj, Jain, and
Jain
2010 Public clouds provide organizations with the flexibility to choose between multiple cloud computing vendors and a pay-as-you-go feature.
Third-party flexibility than past computing methods.
flexibility
Private Cloud
Sotomayor et al. 2009 Private cloud deployments provide local users with a flexible and agile
Self-owned infrastructure
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private infrastructure to operate service workloads within their administrative domain.
Chow et al. 2009 Traditional security, availability, and third-party data control are prompting some companies to build private Sultan 2009 A private cloud requires a team of
network, database, and system management experts to maintain the system.
Cloud service sustainability
Chang, Wills, and Roure
2010 Cloud computing provides added value for organizations, saving costs in operations, resources and staff, as well as providing new business opportunities for service-oriented models. Achieving long-term sustainability is an important success factor for organizations.
Cloud service sustainability
The previous literature review allows us to conclude that there are three features of public clouds:
(1) Third-party outsourcing – Cloud-implementing companies must outsource the implementation to a third-party company due to a relative lack of knowledge regarding cloud implementation.
(2) Accessibility – The concept of accessibility may be provided via the Internet, which is also critical to cloud computing, as cloud computing services should be accessible to all those qualified to access it.
(3) Scalability and flexibility – Business fluctuates according to high and low seasons. During high seasons, companies ought to meet a large amount of need coming from its customers, and it is superfluous to own a massive quantity of software and hardware simply to meet that need. Therefore, cloud computing should allow companies to scale up and down computing capacity and to be flexible in switching between different services when necessary.
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We also summarize two features of private clouds:
(1) Self-owned infrastructure – Private clouds enable companies to have more control of the technology, which stems from the increased possession of cloud software and hardware. Companies may either build their own infrastructure maintained by their staff or own a private computing site external to their organization that is used solely by them.
(2) Cloud service sustainability – Due to the nature of private clouds, companies adopting this type of cloud service must maintain its operation and even have a group of IT maintainers responsible for providing services in order and in use.
This research concludes several features of both public and private clouds. To ensure that these features will result in positive effects and benefits, companies should be aware of their readiness to implement cloud computing.