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| CLOUD COMPUTING |
The Greek myths tell
of creatures plucked from the surface of the Earth and enshrined as
constellations in the night sky. Something similar is happening today in the
world of computing. Data and programs are being swept up from desktop PCs and
corporate server rooms and installed in “the compute cloud”. In general, there
is a shift in the geography of computation.
An
emerging computer paradigm where data and services reside in massively scalable
data centers in the cloud and can be accessed from any connected devices over
the internet. Like other definitions of topics like these, an understanding of
the term cloud computing requires an understanding of various other terms which
are closely related to this. While there is a lack of precise scientific definitions
for many of these terms, general definitions can be given. Cloud computing is
an emerging paradigm in the computer industry where the computing is moved to a
cloud of computers. It has become one of the buzz words of the industry. The
core concept of cloud computing is, quite simply, that the vast computing
resources that we need will reside somewhere out there in the cloud of computers
and we’ll connect to them and use them as and when needed. Computing can be
described as any activity of using and/or developing computer hardware and
software. It includes everything that sits in the bottom layer, i.e. everything
from raw compute power to storage capabilities. Cloud computing ties together
all these entities and delivers them as a single integrated entity under its
own sophisticated management.
Cloud
is a term used as a metaphor for the wide area networks (like internet)or any
such large networked environment. It came partly from the cloud-like symbol used
to represent the complexities of the networks in the schematic diagrams. It represents
all the complexities of the network which may include everything from cables,
routers, servers, data centers and all such other devices.
Computing
started off with the mainframe era. There were big mainframes and everyone
connected to them via “dumb” terminals. This old model of business computing
was frustrating for the people sitting at the dumb terminals because they could
do only what they were “authorized” to do. They were dependent on the computer
administrators to give them permission or to fix their problems. They had no
way of staying up to the latest innovations. The personal computer was a
rebellion against the tyranny of centralized computing operations. There was a
kind of freedom in the use of personal computers. But this was later replaced
by server architectures with enterprise servers and others showing up in the
industry. This made sure that the computing was done and it did not eat up any
of the resources that one had with him. All the computing was performed at
servers. Internet grew in the lap of these servers. With cloud computing we
have come a full circle. We come back to the centralized computing
infrastructure. But this time it is something which can easily be accessed via
the internet and something over which we have all the control.
There are
many types of public cloud computing:
- Infrastructure as a service (IaaS)
- Platform as a service (PaaS)
- Software as a service (SaaS)
- Storage as a service (STaaS)
- Security as a service (SECaaS)Data as a service (DaaS)
- Test environment as a service (TEaaS)
- Desktop as a service (DaaS)
- API as a service (APIaaS)
Software as a Service (SaaS)
This is the most
widely used Cloud Computing approach to date. A business application can be run
on the centralized servers(cloud) rather than running them on on-site
servers/software systems. On Demand
Software as a
service, delivers a single application through the browser to thousands of
customers using a multitenant architecture. In the cloud service side, it only
requires to maintain and manage one application on the cloud and in the client
side, there are no any need of upfront investing on servers, software and
license etc.
EXAMPLE
“Salesforce, Google,
NetSuit, Taleo, Concur Technologies”
Platform as a Service (PaaS)
PaaS delivers
development environments as a service. You build your own applications that run
on the provider's infrastructure and are delivered to your users via the
Internet from the provider's servers.
EXAMPLE
“Salesforce's
platform, WSo2 Stratos, Amazon Elastic Compute Cloud (EC2), Google App Engine,
Coghead, Yahoo pipes, Windows Azure”
Infrastructure as a Service (IaaS)
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| CLOUD COMPUTING |
Infrastructure as a
Service, is very much the backbone of the entire cloud computing concept. A
well known examples include, Infrastructure vendors environments like Google
gears which allow users to build applications and Cloud storages, such as
Amazon Simple Storage Service (S3) which allows user to store and retrieve any
amount of data, at any time, from anywhere on the web.
EXAMPLE
“Google Gears, Amazon
S3”
Types
of clouds
There are different types of clouds
that you can subscribe to depending on your needs. As a home user or small
business owner, you will most likely use public cloud services.
1.Public Cloud - A public cloud can be
accessed by any subscriber with an internet connection and access to the cloud
space.
2.Private Cloud - A private cloud is
established for a specific group or organization and limits access to just that
group.
3.Community Cloud - A community cloud
is shared among two or more organizations that have similar cloud requirements.
4.Hybrid Cloud - A hybrid cloud is
essentially a combination of at least two clouds, where the clouds included are
a mixture of public, private, or community.
Characteristics of Cloud Computing
1. Self Healing
Any application or any service
running in a cloud computing environment has the property of self healing. In
case of failure of the application, there is always a hot backup of the
application ready to take over without disruption. There are multiple copies of
the same application - each copy updating itself regularly so that at times of
failure there is at least one copy of the application which can take over
without even the slightest change in its running state.
2. Multi-tenancy
With
cloud computing, any application supports multi-tenancy - that is multiple
tenants at the same instant of time. The system allows several customers to
share the infrastructure allotted to them without any of them being aware of
the sharing. This is done by virtualizing the servers on the available machine
pool and then allotting the servers to multiple users. This is done in such a
way that the privacy of the users or the security of their data is not
compromised.
3. Linearly Scalable
Cloud
computing services are linearly scalable. The system is able to break down the
workloads into pieces and service it across the infrastructure. An exact idea
of linear scalability can be obtained from the fact that if one server is able
to process say 1000 transactions per second, then two servers can process 2000
transactions per second.
4. Service-oriented
Cloud
computing systems are all service oriented - i.e. the systems are such that
they are created out of other discrete services. Many such discrete services
which are independent of each other are combined together to form this service.
This allows re-use of the different services that are available and that are
being created. Using the services that were just created, other such services
can be created.
5. SLA Driven
Usually
businesses have agreements on the amount of services. Scalability and
availability issues cause clients to break these agreements. But cloud
computing services are SLA driven such that when the system experiences peaks
of load, it will automatically adjust itself so as to comply with the
service-level agreements. The services will create additional instances of the
applications on more servers so that the load can be easily managed.
6. Virtualized
The
applications in cloud computing are fully decoupled from the underlying
hardware. The cloud computing environment is a fully virtualized environment.
7. Flexible
Another
feature of the cloud computing services is that they are flexible. They can be
used to serve a large variety of workload types -varying from small loads of a
small consumer application to very heavy loads of a commercial application.
Cloud
Computing Services
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| CLOUD COMPUTING |
Even though cloud computing is a
pretty new technology, there are many companies offering cloud computing
services. Different companies like Amazon, Google, Yahoo, IBM and Microsoft are
all players in the cloud computing services industry. But Amazon is the pioneer
in the cloud computing industry with services like EC2 (Elastic Compute Cloud)
and S3 (Simple Storage Service) dominating the industry. Amazon has an
expertise in this industry and has a small advantage over the others because of
this. Microsoft has good knowledge of the fundamentals of cloud science and is
building massive data centers. IBM, the king of business computing and
traditional supercomputers, teams up with Google to get a foothold in the clouds.
Google is far and away the leader in cloud computing with the company itself
built from the ground up on hardware.
Benefits:
Cloud
services free businesses and consumers from having to invest in hardware or
install software on their devices. They reduce maintenance and hardware upgrading
needs; because the solutions are all Web-based, even older computers can be
used to access cloud services.
For
mobile users especially, cloud computing provides incredible flexibility with
which professionals can work from any computing device, as long as they have
access to the Web. It also makes collaboration easier, since distributed teams
(or a combination of mobile workers and in-office staff) can work on shared
information stored centrally in the cloud via, for example, online group ware applications.
Working in the
Cloud:
There
are some obstacles to cloud computing. An Internet connection is obviously necessary to take full advantage
of a cloud service. When you’re offline–or if there are any disruptions with
the cloud service itself–the data may not be accessible at all. (Some cloud
apps, like Gmail, have offline capability; others, like Mint, require an
Internet connection. The note taking application, Ever note, offers a good
in-between or hybrid solution, with both desktop/phone software and an online
service that syncs your notes to the cloud.)
But
generally, in my opinion, For now cloud computing’s greatest beneficiaries may
be remote workers, as Web-based apps empower us to be truly mobile and still
accomplish our work.
How can you use the cloud?
The cloud makes it possible for you to access your information
from anywhere at any time. While a traditional computer setup requires you to
be in the same location as your data storage device, the cloud takes away that
step. The cloud removes the need for you to be in the same physical location as
the hardware that stores your data. Your cloud provider can both own and house
the hardware and software necessary to run your home or business applications.
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| CLOUD COMPUTING |
This
is especially helpful for businesses that cannot afford the same amount of
hardware and storage space as a bigger company. Small companies can store their
information in the cloud, removing the cost of purchasing and storing memory
devices. Additionally, because you only need to buy the amount of storage space
you will use, a business can purchase more space or reduce their subscription
as their business grows or as they find they need less storage space.
One requirement is that you need to have an internet connection in
order to access the cloud. This means that if you want to look at a specific
document you have housed in the cloud, you must first establish an internet
connection either through a wireless or wired internet or a mobile broadband
connection. The benefit is that you can access that same document from wherever
you are with any device that can access the internet. These devices could be a
desktop, laptop, tablet, or phone. This can also help your business to function
more smoothly because anyone who can connect to the internet and your cloud can
work on documents, access software, and store data. Imagine picking up your
smartphone and downloading a .pdf document to review instead of having to stop
by the office to print it or upload it to your laptop. This is the freedom that
the cloud can provide for you or your organization.
Risks |
| CLOUD COMPUTING PROS AND CONS |
- Dependency on the Network
The simplest and most obvious
drawback to cloud computing arises out of its most important characteristic: it
is network based. Like anything else dependent on internet connectivity, it is
susceptible to outages and service interruptions at any time. On the other
hand, in-house servers are hard-wired. While users may not be able to access
the data from anywhere, they can be certain that while in the office, their
connection to the server will remain steady. Furthermore, cloud computing is
also susceptible to simple bandwidth issues. Everyone has most likely
experienced this when attempting to utilize the internet at “peak hours” (this
is especially true on college campuses such as Princeton, typically between the
hours of 10pm and 1am, when the sheer number of users strains the network and
as a result, everyone's connection speed suffers). In the context of cloud
computing, if the vendor's servers are being strained at peak hours, both the
performance and availability of its services suffers for its clients. While
most vendors have the redundancy to handle their peak load, there is always the
risk of unforeseen events, server failures, or outside attack; any of which
would threaten client access.
- Difficulty Creating Hybrid Systems—For some users, such as the federal government, some data is just too sensitive to transfer off-site, regardless of the benefits to efficiency or performance. Furthermore, those same larger companies who already fund their own in-house IT department are typically reluctant to throw away their substantial investment in technicians, hardware, and software. Because of the difficulty to integrate an in-house IT department with a cloud service, these groups typically avoid the move to cloud computing, despite all the benefits. Why is it so difficult to integrate an in-house IT department with a cloud service? Each IT department is usually internally consistent, but there is no standardized form from business to business. Therefore, integrating an in-house department with a cloud service is like trying to fit a square peg in a round hole: no matter how hard you force it, it just isn't going to go in.
- Centralization—This risk arises out of an aspect of cloud computing that is central to its existence: centralization of both computing and data. Firms outsource their data to a third-party; thus, they become dependent on that company, and a certain symbiotic relationship forms. If the cloud provider has a glitch in their system, or if an upgrade goes bad, their clients could be offline for extended periods of time.
- Data Integrity—Last, but certainly not least, there is always the risk of a security breach within the confines of a huge firm, regardless of the security precautions. This fear becomes even greater when dealing with data storage off-site. Because clients no longer have control over their data, they must trust the cloud vendor to monitor for cybercrime. Furthermore, once you begin to depend on the internet to transfer data between two points, there is also chance that it will be intercepted by a third-party. Current encryption technology makes this point almost moot, but it is important to identify it, since the computing world is constantly changing, both for the good guys, and for the bad. The complexity of the security measures that must be taken increases greatly when data is distributed over a greater area and number of devices
ADVANTAGES
1. Software as a Subscription
1. Software as a Subscription
In a cloud, software resides on a service providers servers external to a
user's computer. In a sense users would not have to buy software for their
computers because the software is loaded per use while the user is online (via
a browser or some kind of connector application). The only models that would
support this type of software use would be a subscription based or pay as you
go model. Instead of shelling $149 for Office Home & Student, a user may
pay a set fee/month; say $5.95/month and the user can tailor their subscription
to meet their needs. This will keep users from buying software that is bundled
with applications the user may not care for. A perfect example of this is the
Office Suite.
2. Reduced Software Maintenance
By keeping the software in the ‘clouds' users can reduce the amount of
maintenance on their computers. Nowadays essentially every program installed on
a computer has an update function that searches for the latest software changes
in order to patch security flaws, correct software issues, and/or introduce new
functionality. When upgrades are made to software on the cloud it does not
affect the user\'s computer, it would not require for the user to restart their
computers, it would simply mean that unless the change affects functionality or
visual elements, the user will be oblivious to those updates and their
computers will never be affected by those updates. A reasonable reduction in
systems maintenance would be expected as a result of this.
3. Increased Reliability
Increased reliability stems from the fact that the cloud runs on systems that
are extremely reliable and provide some form of redundancy. Unless a user takes
the time to setup a backup system for their files or sets up some kind of
redundancy with offsite backups, etc. Users run the risk of losing valuable and
sometime unrecoverable data on their computers. In the case of grid computing
if a storage server on the cloud fails due to hardware or software issues, the
service provider needs only to shift the load over to other servers or bring up
a backup server in its place. If it occurred at a users premises with installed
software a simple issue can turn to hours of technical support over the phone,
costly downtime, and unhappy users and customers.
4. Increased Scalability
Running out of hard drive space at home? Looks like an additional hard drive
along with a visit to a computer technician for installation will solve the
problem. However in a cloud computing environment, storage is not an issue, as
long as you can pay for it. Service providers need only to add servers or shift
load from one server to another to accommodate for the additional use of space.
The same goes for application use, instead of a small business adding
additional servers to handle business transactions all they have to do is contact
the service provider to let them know that they will need additional resources.
5. Cost Reduction
Costs are reduced in a number of ways. Capital expenditures are reduced because
a lot of the load and storage will be shifted over to the service provider who
can provide that service at a lower cost. Aside from decreased capital
expenditures associated with hardware purchases, users would see the cost of
software decrease due to the reduced cost of subscription software. IT staff at
businesses would be reduced because the majority of the maintenance is
performed at the service provider.
6. Environmentally Friendly
One of the greatest advantages of cloud computing is the increased longevity
and use of older hardware used by data centers. This in turn lessens the amount
of electronic waste dumped because equipment is older and increased use of
those resources. When businesses use current assets instead of purchasing
additional hardware they reduce the size of their carbon footprint because it
is one less server that is put into service, it is one less server that is
consuming electricity.
7. Matches Current Computing Trends
The introduction of the netbooks has moved a lot of sales from computers and
laptops with more powerful processors and extended capabilities to less
powerful and more efficient platforms . This signals that users are looking for
computers that meet their needs and are affordable. The advent of cloud
computing will be able to match this trend because a lot of the processing
overhead is performed at the servers and not the computer, so the need for an
extremely powerful computer is muted. As cloud computing matures and more and
more processing is shifted to the cloud, computers will require less processing
power and will have basic functionality.
8. Portability/Accessibility
One the greatest advantages to grid computing is the availability of files and
software anywhere that there is an active internet connection. This brings
forth added accessibility and productivity for those that are on the road and
require access to files and software. With a large number of companies looking
for alternatives to employees working at the office and the increasing number
of employees making up a mobile workforce. The reduction in application costs
and technical support would easily continue to support this trend towards a
mobile workforce that would utilize the computer grid.
9. Efficient Use of Computer Resources
The advent of virtualization has provided companies with ways to efficiently
used their computer resources. Users no longer require separate servers for
different applications. With virtualization multiple server technologies can
run from a single server. This shift to virtualization supports the growth of
cloud computing due to the increased capabilities of servers. Cloud computing
would also simplify IT's role in computer management because computers would be
software agnostic.
10. Version less Software
Version less software refers to the elimination of software upgrade projects.
Changes and updates to software would be constant and version numbers would be
transparent to the user, all the user would see is added functionality. It
would also give users '…access to new technology early and often rather than
forcing them to wait for a final, packaged product to be shipped. ' This
concept will enable the enterprise to remain in the cutting edge of technology
and would reduce training costs associated with new software releases.
As one can see the case for cloud computing is quite appealing. The shift
towards cloud computing would enable businesses to save money while minimizing
their impact on the environments. Users would have the flexibility of accessing
information from anywhere on the planet where an internet connection exists.
Everyone will benefit from the increased availability and affordability of
applications that were beyond their reach due to cost and complexity with
maintenance and installation. Lastly the need for additional training
associated with new product releases would be eliminated to due to the nature
of the applications constant changing state.
DISADVANTAGES
Unfortunately, Cloud Computing might also be costly to consumers. Although some
web-based apps are free, it's expected that some applications will require a
monthly or yearly fee. In the end, these fees might add up to more than what
you would pay to download and install the software to your computer. There is
also the concern of not being able to work on your files when you do not have
access to the Internet. Business travelers may have to take this into
consideration when deciding to use software online or offline.
Security is another issue. In Cloud Computing, your files are stored on a
remote server, instead of within the privacy of your own home computer.
Although your data is protected by a username and password, some worry that
files will be more accessable to hackers, or that glitches on the part of the
software company may expose private information. The flipside of this concern
is that many home computers are easily compromised, due to viruses, spyware
Still, software companies
are changing gears and giving people the opportunity to use their services
online. Users are starting to reconsider their ideas of what they actually need
to install on their computer, and what they can comfortably store online.
WHAT IS CLOUD COMPUTING
WHAT IS CLOUD COMPUTING? WHAT ARE ITS ADVANTAGES?
