Cloud computing allows users to access files and applications over the internet from any device. There are two models of cloud computing - deployment models which define access types like public, private, hybrid and community clouds, and service models which are infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS). IaaS provides on-demand access to servers, storage, networking and operating systems, PaaS provides platforms for developers to create and deploy applications, and SaaS provides access to applications over the internet.

1. TYPES OF CLOUD COMPUTING
BY,
BALARAMAN

2. Cloud computing:
Cloud Computing is the use of hardware and
software to deliver a service over a network
(typically the Internet). With cloud computing,
users can access files and use applications
from any device that can access the Internet.
Eg: Gmail - Gmail users can access files and
applications hosted by Google via the internet
from any device.

3. Working models for cloud
computing:
There are two working models for cloud
computing. They are
• Deployment Model
• Service Model

4. Deployment Model:
It define the type of access to the cloud.
Cloud can have any of the four types of the
access:
• Public
• Private
• Community
• Hybrid

5. Contd.:
• PUBLIC CLOUD :
It allows systems and services to be easily
accessible to the general public. Public cloud may
be less secure because of its openness.
Eg: E-Mail
• PRIVATE CLOUD : The Private Cloud allows
systems and services to be accessible within an
organization. It offers increased security because
of its private nature.

6. Contd.:
• COMMUNITY CLOUD : The Community Cloud
allows systems and services to be accessible by
group of organizations.
• HYBRID CLOUD : The Hybrid Cloud is mixture
of public and private cloud. However, the critical
activities are performed using private cloud
while the non-critical activities are performed
using public cloud.

7. Service Model:
Cloud computing is based on service model.
There are three service model available...
• Infrastructure as a Service - (IaaS)
• Platform as a Service - (PaaS)
• Software as a Service - (SaaS)

8. Infrastructure as a Service - IaaS:
• IaaS is a way to deliver a cloud computing infrastructure
like server, storage, network and operating system.
• The customers can access these resources over cloud
computing platform i.e Internet as an on-demand
service.
• In IaaS, you buy complete resources rather than
purchasing server, software, datacenter space or network
equipment.
• IaaS was earlier called as Hardware as a Service(HaaS). It
is a Cloud computing platform based model.
• Eg.: Amazon Web Services (AWS), Microsoft Azure

9. IaaS contd.:
• Advantage:
 Cost saving
 Flexibility
 It can also run when server goes down
 On-demand scalability- One of the greatest
benefits of IaaS is that we don’t have to upgrade
software, hardware or troubleshoot equipment
problems. It can be scaled up and down quickly in
response to a company’s requirements

10. IaaS:
• Disadvantage:
 Technical Problems:
Organizations faces some downtime with
IaaS, and it will restrict their access to
applications and data.
Internet connection is a must.
IaaS depends on virtualization services.

11. Platform as a Service - (PaaS):
• PaaS is a programming platform for developers.
This platform is generated for the programmers
to create, test, run and manage the applications.
• A developer can easily write the application and
deploy it directly into PaaS layer.
• PaaS gives the runtime environment for
application development and deployment tools.
• Google Apps Engine(GAE), Windows Azure,
SalesForce.com are the examples of PaaS.

12. PaaS:
• Advantage:
 PaaS is easier to develop.
Developer can concentrate
on the development and
innovation without worrying
about the infrastructure.
 In PaaS, developer only
requires a PC and an Internet
connection to start building
applications.
• Disadvantage:
 One developer can write
the applications as per
the platform provided by
PaaS vendor hence the
moving the application
to another PaaS vendor
is a problem.

13. Software as a Service - (SaaS):
• Software as a service (or SaaS) is a way of
delivering applications over the Internet—as a
service. Instead of installing and maintaining
software, you simply access it via the Internet.
• SaaS applications are sometimes called Web-
based software, on-demand software, or
hosted software.
• Eg.: Youtube, hotstar, Google Apps, Netflix etc.

14. SaaS:
• Advantage:
 Easy to buy
 Minimization of
Hardware Requirement
 Low Maintenance: SaaS
removes the daily
problem of installing,
maintaining and
updating software.
• Disadvantage:
• Internet Connection: is
a major issue. Without
internet connection,
SaaS applications are
unusable.
• Slower speeds.