Definition: Cloud Computing
By David W Christie
We all keep hearing the term "Cloud Services" or "Cloud Computing, but what is it referring
to? The Internet has for many years been referred to as the Cloud, with TCP/IP being the suite
of protocols used to make the Internet function. Data goes into the cloud and is delivered
to another area of the World determined by a unique destination IP Address.
Cloud computing is constantly evolving, but is essentially a network infrastructure with
servers, platforms, applications and storage facilities. A network of shared resources that
can be quickly provisioned in response to customer demand. If you need computer storage space
for a day, a week or a year, there are many providers who will offer that service for a competitive
price. Cloud Computing allows us to have an On-Demand service from anywhere in the World, provided
we have an Internet connection.
There are quite a few service models evolving, but the fundamental service models are:
1. IaaS - Infrastructure as a Service
2. PaaS - Platform as a Service
- Software as a Service
Software as a Service (SaaS) allows subscribers to use the Cloud Provider's software
applications running on their infrastructure from a subscribers terminals connected to the
Internet. It often requires the use of Thin Client software running through a local Web Browser
application. The subscriber merely uses the provider's network with all its complexity to carry
out the required tasks.
Platform as a Service (PaaS) allows the subscriber to use computer or server platforms
to host and run their own applications. The provider controls the use of the infrastructure,
platforms and services. The subscriber controls the use of their own applications and the environment
they run in.
Infrastructure as a Service (IaaS) provides the subscriber with an infrastructure
over which to conduct their network operations. The subscriber is given control of specific
infrastructure such as servers, operating systems, storage devices and security devices to
name a few.
The biggest use of the Cloud is probably the ability to store personal or company information
and the ability to access that information.
Although the biggest area of this type of computing is in the Public Domain, where providers
offer these services to the general public, either private individuals or companies, there
are other models for the use of Cloud Computing.
Up to now we have eluded to the Public cloud. but other network types include:
Private Cloud - This is a network that is operated on behalf of a company or organisation.
In some cases it may be managed or hosted by a third party organisation, but is still solely
for the use of a single organisation.
Community Cloud - As it's name suggests, the network resources are shared by a
number of organisations or businesses that have a common purpose. Again this type of network
can be managed by the organisations themselves or by a third party organisation.
Hybrid Cloud - This can be a complex network with elements of public, private
and community cloud networks that run common technologies.
There have been, and still are, security concerns over this type of computing. We all know
that the Internet can be a dangerous place with more vulnerabilities being uncovered almost daily.
Company and private networks are open to attacks for all sorts of reasons, which result
in malicious damage or compromise of data.
A provider that hosts services such as storage for many thousands of organisations or
companies is almost certainly identified as a more important target to those that might want
to breach any security. A breach would yield access to much more data and therefore the
damage could be much more severe. I suppose the question to ask is "do you trust your
provider to keep your data safe"?
There is no doubt about it that Cloud Computing is here to stay and will only continue
to grow, but it is up to individual organisations to weigh up the advantages and assess the
security risks before accessing these services.
This article relating to Cloud Computing was written by David Christie, MD at
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