Chapter 2 Operating Systems 69
typically designed with limited CPU and memory
support. For example, they will not support
extensive graphics associated with games or
sophisticated graphic design programs, such as
some web design software or computer-aided
drafting and engineering software. In general, the
mobile operating system is designed to provide
the widest assortment of popular user applications
on limited hardware with a minimal amount of
software required to perform a task. Common
portable device tasks are Internet access and
collaboration activities, such as instant messaging,
texting, Facebook, Twitter, taking photos, and
sharing music and photos. As mobile device
operating systems and mobile devices evolve, it
will soon be difficult to discern between what is
considered a mobile device and what is not.
Cloud Computing
Cloud computing is accessing a shared
pool of resources and specialized services over
the Internet. Examples of shared resources and
services are storage, application software, instant
messaging, e-mail, and database support. The
term cloud is synonymous with the Internet
symbol used in network drawings, Figure 2-34.
The cloud symbol represents the Internet location
of a service. The cloud computing concept is not
as new as you might think. It has actually been
around for many years, even before the term
cloud was used. If you have ever used Hotmail,
Facebook, or an online photo sharing or online
gaming program, then you have used a cloud-
based system.
Cloud services have expanded rapidly in
recent years because of mobile devices, such as
smartphones and tablets. These two types of
mobile devices do not have sufficient memory,
storage space, or powerful CPUs, which is why
the demand for cloud services has increased. The
cloud provides storage services and the ability
to use large software applications, which cannot
possibly be installed on the portable device. For
example, a mobile user can access the complete
Microsoft Office suite via the Internet using a
portable device. The success of mobile devices
depends greatly on cloud computing.
Typically, users install the entire software
application on their computer. After installation,
they have complete access and control over the
use and configuration of the software application.
Users can also store files on their computer as
related to the software application. In a cloud
computing setting, the user would install a small
software application, or app, which allows the
user to access the larger software application on
the cloud service. The software appears to the
user as though it is installed entirely on the PC
or portable device, when in reality the software
application is installed on the cloud server. In this
scenario, the user’s computer is referred to as a
thin client. A thin client depends on the cloud-
based software application to do most of the work.
The user has the option to store the document
on the cloud location or on the computer. When
software applications are provided through cloud
services, it is often referred to as virtualization.
Cloud services can be provided free of charge
or for a cost. When free of charge, fewer services
and less storage space are provided as compared
to pay services. There are many cloud service
providers such as Google, Apple, Microsoft,
Amazon, VMware, IBM, and other private
companies.
The real strength of cloud computing is
resource pooling and sharing of resources.
Computer resources such as documents, pictures,
videos, and other types of files can be easily
shared with members of the cloud service. In
addition to sharing resources, the cloud service
provider typically makes available software
applications appropriate for the type of cloud
Internet
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Figure 2-34. The Internet is represented as a cloud on
network drawings.