Environmental Engineering Reference
In-Depth Information
Cloud) is a web service that provide computing
capacity in the cloud. Amazon EC2's web service
interface allows clients to obtain and configure
capacity. It runs within Amazon's data centers,
and is managed by Amazon's technical support
staff. Amazon EC2 helps provision new server
resources via the Internet without the hardware
and operational expenses (Poniatowski, 2010).
Cloud computing is a way to increase capac-
ity and add capabilities without investing in new
infrastructure, training new staff and licensing new
software. By pooling resources into large clouds,
companies can cut down costs and increase uti-
lization by delivering resources only for as long
as those resources are needed. Cloud computing
allows individuals, teams and organizations to
streamline procurement processes and eliminate
the need to duplicate certain computer adminis-
trative skills related to configuration and support.
A cloud computing have the potential to reduce
enterprise energy dependency. Today data cen-
ters are overcrowded, consuming a huge amount
of energy resources. Cloud computing allows
companies to evolve to a greener, more holistic
approach for data center management, permits
to achieve greater economies of scale, workload
balancing and the integration of IT services with
power and facilities management. With its focus
on resource conservation, cloud computing en-
courages goods service management practices
like enterprise content management, which helps
keep the volume of active data under control via
regular archival and disposal of redundant data.
Companies and government agencies are using
cloud computing to make services and applica-
tions accessible and economical for emerging
nations - providing the means to improve their
agriculture production, healthcare, education
systems (CIO, 2009). Around the world people
with mobile devices will be able to connect with
a cloud infrastructure for real-time services and
information. IBM recommends that companies put
in place three fundamental prerequisites in order
return on investment: dynamic infrastructure, IT
services affinity assessment and cloud strategy.
Virtualization, which is regarded as the corner-
stone technology for all cloud computing archi-
tecture is mainly used for abstraction and sharing
the IT resources. Virtualization allows unifying
raw hardware, storage and network resources as
well as encapsulation of resources i.e. applications
ultimately improve security, manageability and
isolation. Another important feature of clouds is
the integration of hardware and system software
with applications. Both hardware and system
software, or infrastructure and the applications
are offered as a service in an integrated manner.
IaaS (Infrastructure as a Service) offers com-
prise computing resources such as processing
or storage which can be obtained as a service.
Examples are Amazon Web Services with its EC2
(Elastic Compute Cloud) for processing and S3
(Simple Storage Service) for storage. Instead of
selling raw hardware infrastructure, IaaS provid-
ers typically offer virtualized infrastructure as a
service. Therefore, hardware level resources are
abstracted and encapsulated and exposed to up-
per layer and to end users through standardized
interface as unified resources. PaaS (Platforms as
a Service) offers are targeted at software devel-
opers, which can write applications according to
the specification of a particular platform without
needing to worry about the underlying hardware
infrastructure. PaaS offers can cover all phases
of software development or may be specialized
around a specific area like content management.
Examples are the Google App Engine, which
allows applications to be run on Google' infra-
structure and Salesforce's Force.com platform.
Software as a Service (SaaS) is software that is
managed and distributed in a pay-per-use man-
ner. For user, obtaining software as a service is
mainly motivated by cost advantages due to the
utility-based payment model. Examples of SaaS
offers are Salesforce.com and Google Apps such
as Google Mail and Google Docs and Spreadsheets
(Stanoevska-Slabeva & Wozniak, 2010a).
