Unit-1

Cloud Computing means storing and accessing the data and programs on remote servers
that are hosted on the internet instead of the computer’s hard drive or local server. Cloud
computing is also referred to as Internet-based computing, it is a technology where the
resource is provided as a service through the Internet to the user. The data that is stored
can be files, images, documents, or any other storable document.

How Cloud Computing Works?

Cloud computing helps users in easily accessing computing resources like storage and
processing over the internet rather than local hardware. Here we are discussing how it
works in a nutshell:
 Infrastructure: Cloud computing depends on remote network servers hosted on internet
for store, manage, and process the data.
 On-Demand Access: Users can access cloud services and resources based on-
demand they can scale up or down the without having to invest for physical hardware.
 Types of Services: Cloud computing offers various benefits such as cost saving,
scalability, reliability and accessibility it reduces capital expenditures, improves
efficiency.

History of Cloud Computing

 Before Computing was come into existence, client Server Architecture was used where
all the data and control of client resides in Server side. If a single user want to access
some data, firstly user need to connect to the server and after that user will get
appropriate access. But it has many disadvantages. So, After Client Server computing,
Distributed Computing was come into existence, in this type of computing all computers
are networked together with the help of this, user can share their resources when
needed. It also has certain limitations. So in order to remove limitations faced in
distributed system, cloud computing was emerged.
 During 1961, John MacCharty delivered his speech at MIT that “Computing Can be sold
as a Utility, like Water and Electricity.” According to John MacCharty it was a brilliant
idea. But people at that time don’t want to adopt this technology. They thought the
technology they are using efficient enough for them. So, this concept of computing was
not appreciated much so and very less will research on it. But as the time fleet the
technology caught the idea after few years this idea is implemented. So, this is
implemented by Salesforce.com in 1999.

 This company started delivering an enterprise application over the internet and this way
the boom of Cloud Computing was started.

 In 2002, Amazon started Amazon Web Services (AWS), Amazon will provide storage,
computation over the internet. In 2006 Amazon will launch Elastic Compute Cloud
Commercial Service which is open for Everybody to use.

 After that in 2009, Google Play also started providing Cloud Computing Enterprise
Application as other companies will see the emergence of cloud Computing they also
started providing their cloud services. Thus, in 2009, Microsoft launch Microsoft Azure
and after that other companies like Alibaba, IBM, Oracle, HP also introduces their Cloud
Services. In today the Cloud Computing become very popular and important skill.
Advantages
The following are some of the benefits of using cloud computing:
 It is easier to get backup in cloud.
 It allows us easy and quick access stored information anywhere and anytime.
 It allows us to access data via mobile.
 It reduces both hardware ad Software cost, and it is easily maintainable.
 One of the biggest advantage of Cloud Computing is Database Security.
Disadvantages
The following are some of disadvantages you will face while using cloud computing:
 It requires good internet connection.
 User have limited control on the data.

Architecture Of Cloud Computing

Cloud computing architecture refers to the components and sub-components required for
cloud computing. These components typically refer to:
1. Front end ( Fat client, Thin client)
2. Back-end platforms ( Servers, Storage )
3. Cloud-based delivery and a network ( Internet, Intranet, Intercloud )

1. Front End ( User Interaction Enhancement )

The User Interface of Cloud Computing consists of 2 sections of clients. The Thin
clients are the ones that use web browsers facilitating portable and lightweight
accessibilities and others are known as Fat Clients that use many functionalities for
offering a strong user experience.
2. Back-end Platforms ( Cloud Computing Engine )
The core of cloud computing is made at back-end platforms with several servers for
storage and processing computing. Management of Applications logic is managed
through servers and effective data handling is provided by storage. The combination
of these platforms at the backend offers the processing power, and capacity to
manage and store data behind the cloud.
3. Cloud-Based Delivery and Network
On-demand access to the computer and resources is provided over the Internet,
Intranet, and Intercloud. The Internet comes with global accessibility, the Intranet helps in
internal communications of the services within the organization and the Intercloud enables
interoperability across various cloud services. This dynamic network connectivity ensures
an essential component of cloud computing architecture on guaranteeing easy access and
data transfer.

Evolution of Cloud Computing

“Cloud Computing” was first introduced in the 1950s to describe internet-related services,
and it evolved from distributed computing to the modern technology known as cloud
computing. Cloud services include those provided by Amazon, Google, and Microsoft.
Cloud computing allows users to access a wide range of services stored in the cloud or on
the Internet. Cloud computing services include computer resources, data storage, apps,
servers, development tools, and networking protocols.

1. Mainframe Computing(1950-1970)
Mainframes which first came into existence in 1951 are highly powerful and reliable
computing machines. These are responsible for handling large data such as massive input-
output operations. Even today these are used for bulk processing tasks such as online
transactions etc. These systems have almost no downtime with high fault tolerance. After
distributed computing, these increased the processing capabilities of the system. But these
were very expensive. To reduce this cost, cluster computing came as an alternative to
mainframe technology.
2. Distributed Systems(1970-1980)
Distributed System is a composition of multiple independent systems but all of them are
depicted as a single entity to the users. The purpose of distributed systems is to share
resources and also use them effectively and efficiently. Distributed systems possess
characteristics such as scalability, concurrency, continuous availability, heterogeneity, and
independence in failures. But the main problem with this system was that all the systems
were required to be present at the same geographical location. Thus to solve this problem,
distributed computing led to three more types of computing and they were-Mainframe
computing, cluster computing, and grid computing.
3. Cluster Computing(1980-1990)
In 1980s, cluster computing came as an alternative to mainframe computing. Each machine
in the cluster was connected to each other by a network with high bandwidth. These were
way cheaper than those mainframe systems. These were equally capable of high
computations. Also, new nodes could easily be added to the cluster if it was required. Thus,
the problem of the cost was solved to some extent but the problem related to geographical
restrictions still pertained. To solve this, the concept of grid computing was introduced.
4. Grid Computing(1990-2000)
In 1990s, the concept of grid computing was introduced. It means that different systems
were placed at entirely different geographical locations and these all were connected via the
internet. These systems belonged to different organizations and thus the grid consisted of
heterogeneous nodes. Although it solved some problems but new problems emerged as the
distance between the nodes increased. The main problem which was encountered was the
low availability of high bandwidth connectivity and with it other network associated issues.
Thus. cloud computing is often referred to as “Successor of grid computing”.
5. Utility Computing(Late 1990-2000)
Utility Computing is a computing model that defines service provisioning techniques for
services such as compute services along with other major services such as storage,
infrastructure, etc which are provisioned on a pay-per-use basis.
6. Virtualization(1980-Present)
Virtualization was introduced nearly 40 years back. It refers to the process of creating a
virtual layer over the hardware which allows the user to run multiple instances
simultaneously on the hardware. It is a key technology used in cloud computing. It is the
base on which major cloud computing services such as Amazon EC2, VMware vCloud, etc
work on. Hardware virtualization is still one of the most common types of virtualization.
7. Web 2.0
Web 2.0 is the interface through which the cloud computing services interact with the
clients. It is because of Web 2.0 that we have interactive and dynamic web pages. It also
increases flexibility among web pages. Popular examples of web 2.0 include Google Maps,
Facebook, Twitter, etc. Needless to say, social media is possible because of this
technology only. It gained major popularity in 2004.
8. Service Orientation
A service orientation acts as a reference model for cloud computing. It supports low-cost,
flexible, and evolvable applications. Two important concepts were introduced in this
computing model. These were Quality of Service (QoS) which also includes the SLA
(Service Level Agreement) and Software as a Service (SaaS) .
What Are Cloud Deployment Models?
The following are the Cloud Deployment Models:
1. Private Deployment Model
It provides an enhancement in protection and customization by cloud resource utilization as
per particular specified requirements. It is perfect for companies which looking for security
and compliance needs.
2. Public Deployment Model
It comes with offering a pay-as-you-go principle for scalability and accessibility of cloud
resources for numerous users. it ensures cost-effectiveness by providing enterprise-needed
services.
3. Hybrid Deployment Model
It comes up with a combination of elements of both private and public clouds providing
seamless data and application processing in between environments. It offers flexibility in
optimizing resources such as sensitive data in private clouds and important scalable
applications in the public cloud.

Characteristics Of Cloud Computing

The following are the characterisitics of Cloud Computing:
1. Scalability
With Cloud hosting, it is easy to grow and shrink the number and size of servers based on
the need. This is done by either increasing or decreasing the resources in the cloud. This
ability to alter plans due to fluctuations in business size and needs is a superb benefit of
cloud computing, especially when experiencing a sudden growth in demand.
2. Save Money
An advantage of cloud computing is the reduction in hardware costs. Instead of purchasing
in-house equipment, hardware needs are left to the vendor. For companies that are growing
rapidly, new hardware can be large, expensive, and inconvenient. Cloud computing
alleviates these issues because resources can be acquired quickly and easily. Even better,
the cost of repairing or replacing equipment is passed to the vendors. Along with purchase
costs, off-site hardware cuts internal power costs and saves space. Large data centers can
take up precious office space and produce a large amount of heat. Moving to cloud
applications or storage can help maximize space and significantly cut energy expenditures.
3. Reliability
Rather than being hosted on one single instance of a physical server, hosting is delivered
on a virtual partition that draws its resource, such as disk space, from an extensive network
of underlying physical servers. If one server goes offline it will have no effect on availability,
as the virtual servers will continue to pull resources from the remaining network of servers.
4. Physical Security
The underlying physical servers are still housed within data centers and so benefit from the
security measures that those facilities implement to prevent people from accessing or
disrupting them on-site.
5. Outsource Management
When you are managing the business, Someone else manages your computing
infrastructure. You do not need to worry about management as well as degradation.

Cloud services are divided into three categories based on functionality:

1. Infrastructure as a Service (IaaS)
 Provides virtualized computing resources over the internet.
 Example: AWS EC2, Google Compute Engine, Microsoft Azure Virtual Machines.
2. Platform as a Service (PaaS)
 Offers a managed platform with built-in tools for developers.
 Example: AWS Elastic Beanstalk, Google App Engine, Heroku.
3. Software as a Service (SaaS)
 Delivers ready-to-use software applications over the internet.
 Example: Google Drive, Dropbox, Salesforce.

Advantages of Cloud Computing

 Cost Saving
 Data Redundancy and Replication
 Ransomware/Malware Protection
 Flexibility
 Reliability
 High Accessibility
 Scalable
Disadvantages of Cloud Computing
 Internet Dependency
 Issues in Security and Privacy
 Data Breaches
 Limitations on Control