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and/or resources they request or need will be available, just like electricity
from the wall socket. And, when it comes to requirements in terms of device
independence and availability, the bar is continually being raised by the
rapid adoption of smart devices (phones, tablets, handhelds and pocket
PCs). Cloud computing is currently one of the strongest trends in the IT
industry.
To be able to understand how the Cloud concept, its various trends,
reservations and lines of argument came about, it is useful to take a closer
look at historic developments in data processing, and the underlying
technologies and approaches that have served both as precursors and
trailblazers for the Cloud. The initial spark for Cloud computing was given by
the success and propagation of virtualisation technologies, and also by
massive improvements in network efficiency. When virtualisation was
extended to disk storage systems and networks, this was the breakthrough
that allowed an abstraction of the hardware layer from the higher‐level
layers. Large‐scale automation, self‐service and elastic provisioning became
the major ingredients for Cloud computing; but these technologies, too,
needed to mature and assert themselves in the course of time, and it is
important to view them in a wider context.
2.1
Cloud Technology
How to evaluate suitability of Cloud computing for your organisation
The suitability of Cloud is dependant on the company or organisation and, of
course, which business it is in. If seen from a software business standpoint,
then there will be more interest in providing a Cloud service and less in
consuming a Cloud service, although there are interesting services for a
software developer as we will see later on in this chapter.
5
The prime considerations can be split into two main domains, the consumer
and the provider of the service. Consumers that are using an IT service,
could be using either a public or a private service. In this book we speak
about a Cloud service and if the service meets the definition for Cloud by the
NIST (National Institute of Standards and Technology).
i.
Public Cloud Services are shared resources that are used by the
general public, and there is normally little or no customisation of this
service possible by the user.
5
An expanded version of this chapter can be found under
