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• Cloud computing is Internet-based
computing, whereby shared resources,
software, and information are provided to
computers and other devices on demand.
• This frequently takes the form of web-based
tools or applications that users can access
and use through a web browser as if it were a
program installed locally on their own
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• Most cloud computing infrastructures consist
of services delivered through common centers
and built on servers.
• Clouds often appear as single points of access
for all consumers' computing needs.
• The major cloud service providers include
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• Customers do not own the physical
• They consume resources as a service and pay
only for resources that they use.
• Sharing "perishable and intangible" computing
power among multiple tenants can improve
utilization rates, as servers are not unnecessarily
left idle (which can reduce costs significantly
while increasing the speed of application
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THREE KINDS OF CLOUD SERVICES
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Software as a Service (SaaS)
• A Software that is deployed over the internet.
• A SaaS application runs entirely in the cloud
that is, on servers at an Internet-accessible
• The on-premises client is typically a browser
or some other simple client.
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Example of a SaaS applications
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• An on-premises application can sometimes
enhance its functions by accessing application-
specific services provided in the cloud.
• Because these services are usable only by this
particular application, they can be thought of as
attached to it.
• One popular consumer example of this is Apple’s
iTunes: The desktop application is useful for
playing music and more, while an attached service
allows buying new audio and video content.
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Example of Attached Services
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Cloud Platforms or
Platform as a Service (PaaS)
• A cloud platform provides cloud-based
services for creating applications.
• Rather than building their own custom
foundation, for example, the creators of a
new SaaS application could instead build on a
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Example of Cloud Platforms or
Platform as a Service (PaaS)
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• Autonomic computing — "computer systems capable of self-
• Client–server computing refers broadly to any distributed
application that distinguishes between service providers
(servers) and service requesters (clients).
• Grid computing — "a form of distributed computing and
parallel computing, whereby a 'super and virtual computer' is
composed of a cluster of networked, loosely coupled
computers acting in concert to perform very large tasks“
• Peer-to-peer – a distributed architecture without the need for
central coordination, with participants being at the same time
both suppliers and consumers of resources.
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4 Cloud Deployment Models
• Private cloud
– enterprise owned or leased
• Community cloud
– shared infrastructure for specific community
• Public cloud
– Sold to the public, mega-scale infrastructure
• Hybrid cloud
– composition of two or more clouds
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Cloud Definition Framework
CloudCloudPrivate CloudPrivate Cloud Public CloudPublic Cloud
Software as a
Platform as a
Infrastructure as a
Broad Network Access Rapid Elasticity
On Demand Self-Service
Low Cost Software
Virtualization Service Orientation
Massive Scale Resilient Computing
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• Agility improves with users' ability to rapidly
and inexpensively re-provision technological
• Cost is claimed to be greatly reduced and
capital expenditure is converted to
• Device and location independence enable
users to access systems using a web browser
regardless of their location or what device
they are using (e.g., PC, mobile).
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Key features (Cont.)
• Multi-tenancy enables sharing of resources
and costs across a large pool of users thus
– Centralization of infrastructure in locations with
lower costs (such as real estate, electricity, etc.)
– Peak-load capacity increases (users need not
engineer for highest possible load-levels)
– Utilization and efficiency improvements for
systems that are often only 10–20% utilized.
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Key features (Cont.)
• Security could improve due to centralization
of data, increased security-focused resources,
etc., but concerns can persist about loss of
control over certain sensitive data, and the
lack of security for stored kernels.
• Security is often as good as or better than
under traditional systems, in part because
providers are able to devote resources to
solving security issues that many customers
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Key features (Cont.)
• Maintenance cloud computing applications
are easier to maintain, since they don't have
to be installed on each user's computer
• The cloud is becoming increasingly associated
with small and medium enterprises (SMEs) as
in many cases they cannot justify or afford the
large capital expenditure of traditional IT.
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• Privacy: Companies hosting the Cloud services
control, and thus, can monitor at will, lawfully or
unlawfully, the communication and data stored
between the user and the host company.
– The relative security of cloud computing services is a
contentious issue which may be delaying its adoption.
– Some argue that customer data is more secure when
managed internally, while others argue that cloud
providers have a strong incentive to maintain trust
and as such employ a higher level of security
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• Availability and Performance:
– Businesses are worried about acceptable levels of
availability and performance of applications
hosted in the cloud.
– There are also concerns about a cloud provider
shutting down for financial or legal reasons, which
has happened in a number of cases.
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• Sustainability and siting
• Cloud computing is often assumed to be a form
of "green computing"
• Siting the servers affects the environmental
effects, of cloud computing.
• In areas where climate favors natural cooling and
renewable electricity is readily available, the
environmental effects will be more moderate.
• Thus countries with favorable conditions, such as
Finland, Sweden and Switzerland, are trying to
attract cloud computing data centers.
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Cloud Computing in HR
Services Being Offered Presently
Leave Application system
Employee data management
Booking of company resources
Performance and talent management modules
Training and development modules etc.
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