Posted by on Apr 4, 2013 in Cloud Computing, IT Definitions | 0 comments

What is Cloud Computing?

What is Cloud Computing?

Cloud computing has the potential to completely revolutionize how technology is delivered and utilized by both business and personal users alike. However, ask a handful of IT experts to give you a definition of cloud computing and you are likely to receive a variety of answers that leave you scratching your head.

This is not altogether a bad thing. Lively debate amongst experts indicates that cloud computing is still somewhat of an evolving concept. As such, the scope of cloud computing is likely to continue to change as its adaption, influence, innovation and maturity grow in the marketplace.

However, in the here and now, this inability to articulate a consistent message has caused widespread confusion about the role and benefits of cloud computing. It is difficult to apply in the real world something that is still not clear in a theoretical sense.

At the heart of the issue lies the fact that cloud computing covers a very broad spectrum of activity. It incorporates a myriad of IT capabilities. These in turn can be applied across a multitude of configurations to suit both small-scale and large-scale projects. In essence, its big, its dynamic but its also flexible and scalable.

Although cloud computing is a huge concept the underlying principles are relatively simple.
Simply put, Cloud Computing can be defined as:

“…the utilization of computer resources that are: –
     i.   available on-demand
     ii.   accessed via a network
     iii.   charged according to usage
     iv.   provided as a service from a cloud vendor”

Essentially that means using computer hardware (e.g. servers, storage etc.) or software (e.g. applications, programs etc.) in an environment that exhibits all four of the conditions above. To illustrate how the basic fundamentals of cloud computing operate in practice we can compare it to another service we use every day that exhibits similar characteristics – Electricity.

Example 1: – Cloud Computing vs. Electricity

When you turn on a light in your home you are using electricity. That electricity was transmitted into your house from a power grid (an integrated network) and was provided as a service from an electricity company.

Similarly, when you access a cloud facility to store files for example you are using software and hardware resources. These resources are available to you across a network (the internet) and provided as a service from a cloud storage vendor.

Cloud Computing vs Electricity

When your light is turned on you are consuming electricity which incurs a cost. As such, every month or quarter you receive a bill from the electricity company. Your bill will include a cost that is dependent on how much electricity you have used in that period (variable cost).

Likewise, when you use your cloud storage facility you will also be charged depending on factors such as storage space used and upload/download bandwidth.

This model of comparison with electricity can be applied to illustrate a number of other cloud computing concepts. For example:

   –  Adding another light (on-demand scalability)
   –  Adding other electrical appliances (accessibility and multi-tenancy)
   –  Power Outages (availability, redundancy and backups)
   –  Using solar panels at home (private networks and cloud bursting)

Additionally, this model can also be applied more holistically to illustrate the concept of cloud computing more broadly.

Example 2: – Generic Cloud Computing Model

As mentioned previously the concept of cloud computing covers many aspects. The model described below (see Example 2) attempts to demonstrate its capabilities more broadly through the following five areas: –

1. The types of services offered through cloud computing can be grouped into three main categories – Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS).

2. Access to these services can be achieved through any device that can connect to a network (e.g. phones, tablets, cameras, computers, servers, terminals etc.).

3. Delivery of services can occur over a public cloud (i.e. over the internet), a private cloud (a network specifically for access by a single entity or organization), or a hybrid cloud (combination of the both public and private clouds).

4. Charges remain according to usage however pricing can be structured more flexibly. For example, making an initial upfront payment may reduce the individual cost per unit, resulting in lower variable costs. Alternatively, a fixed monthly price may be set to utilize a set of resources up to a certain limit.

5. Numerous vendors of varying sizes exist in the cloud computing marketplace. These vendors can specialize in a single area or cover a wide range of cloud services, consulting and support.

ZeusDB Cloud Taxonomy

What are SaaS, PaaS and IaaS?

As mentioned previously, SaaS, Paas and IaaS categorize the services available through cloud computing. As the cloud continues to evolve the distinction between these categories is becoming less clear. A basic definition for each is listed below.

SaaS: – relates to cloud services where fully functional applications are provided from vendors. End users may be able to change some general operational configurations in the application’s interface but the underlying code, data, operating system and infrastructure are managed by the vendor. An example of SaaS would be Webmail.

PaaS: – refers to services where cloud vendors provide end users the resources (hardware and software) that enable them to develop, code and deploy their own applications. The underlying operating system and infrastructure are still managed by the vendor.

IaaS: – are the provision of cloud services that allow end users to control various aspects of hardware and software including servers, storage space, operating systems, software and applications. Cloud vendors still manage the physical infrastructure.

A web host provider is a good example of both PaaS and IaaS. Basic hosting packages allow people to create websites without having to manage any underlying infrastructure. Many hosting companies now also offer Virtual, Dedicated and Cloud Servers to end users, expanding into the IaaS space.


Cloud computing is both a very simple and very complex concept. It covers a huge part of the IT spectrum and as such often causes confusion as to its application, even amongst experts. We hope this article will be helpful in outlining the key components that make up cloud computing.

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