Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources..

2. 
Cloud computing is a model for enabling ubiquitous, convenient, on-demand
network access to a shared pool of configurable computing resources
(e.g., networks, servers, storage, applications, and services) that can be rapidly
provisioned and released with minimal management effort or service provider
interaction.
NIST
Shared Infrastructure
Dynamic Provisioning
Managed Metering
Network Access

3. Cloud computing is an evolving paradigm. It is a potential technology to
change IT Services. The elasticity of resources plays an important part in
cloud computing.
Cloud computing provides,
OnDemand
Services
Broad
Network
Access
Measured
Services
Resource
Rapid
Pooling
Elasticity

4. Public Cloud
Private Cloud
Community Cloud
Hybrid Cloud

7. SaaS
IaaS
PaaS
Softyware as a Service
Platform as a Service
Infrastructure as a Service
-ERP
-Application Developement
-Caching
-CRM
-Web streaming
-Networking
-Email
-Decision Support
-Security
-Collaborative
CONSUME
-System Management
BUILD
HOST

8. Easy Connectivity
Inexpensive
Efficient Storage and Computing
Widespread Availability
Reliable and Redundant

9. 
Cloud computing makes eminent sense for small scale
enterprises. With no upfront investment; it allows SMEs a cost
effective solution with their capital.

It just a flat monthly rate and you’re sorted; no need to worry
about buying those expensive hardware solutions or to take
care of scalability issues.

As per your business demands; you can scale up and down.
Cloud computing provides better functionality then a
conventional solutions which are so expensive.

10. 
Cloud computing provides mobility; be it your office or a
comfort of your own home, you can access your business
software and all you need to do is ‘Login’.

Cloud computing makes sharing a cake walk. It expands your
business boundaries.

Better resilience and security is a key feature of cloud
computing which SMEs couldn’t afford otherwise.

Cloud computing effectively cuts down the labor cost up to
15-20%.

11. 
When it comes to implying mission-critical application; large
scale enterprise gives cloud system a second thought.

As the mission-critical application has sensitive
information, vulnerability issues are higher; that’s the main
reason for large scale enterprise to not adapt cloud
computing as it still contains some deficiencies.

Though the scenario is changing these days, especially after
Microsoft office 365 adopted cloud computing.

12. 
Hybrid cloud is a solution for large scale enterprises when
affordability of public cloud and security of private cloud is
needed.

Cloud computing provides best breed of services if it is
managed well by the large scale enterprises.

Cloud computing implies “Green approach”, we are not just
talking about environment; cloud computing also cuts down
the expenditures of large scale enterprise by 30%. Energy cost
goes tremendously down by adapting cloud computing.

13. 
Cloud computing has several security loopholes which makes it
vulnerable.

Cloud computing is yet to adhere several regulatory requirements
and security laws.

As cyber policy differs from country to country, there are some
legal issues in cloud computing.

Confidentiality is the major issue in cloud system, as all the
information is stored at remote location.

Another big issue with cloud system is encryption; it is very
essential for ensuring the security of data which is yet to be
implemented.

14. 
Denial of Service attack:
Denial of service attacks are the most common hacking attacks. Hackers flood
network host by invalid requests that occupies all the resources. This ultimately
affects in responding the legitimate requests.

Authentication attack:
In hosted and virtual services, authentication is a weak point. The methods and
mechanism used to secure the authentication process are frequently targeted.

Side channel attack:
Malicious virtual machine in close proximity to host system is placed in host
system. Side channel attack has emerged as effective security threat targeting
systems. Hence resilience to side channel attack is important.

Man in middle attack:
In man in middle attack, attacker gets in the middle of our interactions with
others and eavesdrops on data coming back and forth.

15. Research is being done on security issues in cloud computing
system. Researchers are still discovering the security issues
that are needed to be resolved in order to provide reliable
and robust solutions.