CompTIA A+ Certification All-in-One Exam Guide

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Mobile Operating Systems
Most mobile devices run either Apple iOS or Google Android. This section
discusses their development and implementation models, as well as some of
their major features, including how their app stores work.
Development Models
Before we look at each mobile operating system in detail, let’s step back to
consider the big picture. The different underlying philosophies inspiring these
operating systems—and guiding the companies that make them—help us
understand why they do something one way instead of another. We’ll start
with a look at closed source and open source as development models. You
may have heard these terms regarding how software is released and licensed
(if not, Chapter 27, “Securing Computers,” will discuss how these terms
apply to licensing), but they also provide an interesting framework for
looking at how products are developed and released. Then we’ll discuss how
these models apply to operating systems.
Closed Source
When it comes to development models, it may help to think of closed source
as another way to refer to the traditional practice of making and selling a
product without telling anyone how you made it. The traditional model
makes intuitive sense, at least in our culture; how your product is made is a
trade secret—something that gives you a competitive edge—and sharing it
could inspire competitors to use your design, or potential customers to make
it themselves.
Vendor-Specific and Proprietary We sometimes apply the terms
proprietary or vendor-specific to a closed-source product or technology, most
often when we’re trying to highlight something that doesn’t use common,