for ARMv7, like software developed for x86, is sadly not compatible with the Raspberry Pi’s BCM2835—although developers
can usually convert the software to make it suitable.
That’s not to say you’re going to be restricted in your choices. As you’ll discover later in the book, there is plenty of software
available for the ARMv6 instruction set, and as the Raspberry Pi’s popularity continues to grow, that will only increase. In this
book, you’ll also learn how to create your own software for the Pi even if you have no experience with programming.
Windows vs. Linux
Another important difference between the Raspberry Pi and your desktop or laptop, other than the size and price, is the
operating system—the software that allows you to control the computer.
The majority of desktop and laptop computers available today run one of two operating systems: Microsoft Windows or Apple
OS X. Both platforms are closed source, created in a secretive environment using proprietary techniques.
These operating systems are known as closed source for the nature of their source code, the computer-language recipe that tells
the system what to do. In closed-source software, this recipe is kept a closely-guarded secret. Users are able to obtain the
finished software, but never to see how it’s made.
The Raspberry Pi, by contrast, is designed to run an operating system called GNU/Linux—hereafter referred to simply as Linux.
Unlike Windows or OS X, Linux is open source: it’s possible to download the source code for the entire operating system and
make whatever changes you desire. Nothing is hidden, and all changes are made in full view of the public. This open source
development ethos has allowed Linux to be quickly altered to run on the Raspberry Pi, a process known as porting. At the time
of this writing, several versions of Linux—known as distributions—have been ported to the Raspberry Pi’s BCM2835 chip,
including Debian, Fedora Remix and Arch Linux.
The different distributions cater to different needs, but they all have something in common: they’re all open source. They’re also
all, by and large, compatible with each other: software written on a Debian system will operate perfectly well on Arch Linux and
vice versa.
Linux isn’t exclusive to the Raspberry Pi. Hundreds of different distributions are available for desktops, laptops and even mobile
devices; and Google’s popular Android platform is developed on top of a Linux core. If you find that you enjoy the experience
of using Linux on the Raspberry Pi, you could consider adding it to other computing devices you use as well. It will happily
coexist with your current operating system, allowing you to enjoy the benefits of both while giving you a familiar environment
when your Pi is unavailable.
As with the difference between ARM and x86, there’s a key point to make about the practical difference between Windows,
OS X and Linux: software written for Windows or OS X won’t run on Linux. Thankfully, there are plenty of compatible
alternatives for the overwhelming majority of common software products—better still, the majority are free to use and as open
source as the operating system itself.
Getting Started with the Raspberry Pi
Now that you have a basic understanding of how the Pi differs from other computing devices, it’s time to get started. If you’ve
just received your Pi, take it out of its protective anti-static bag and place it on a flat, non-conductive surface before continuing
with this chapter.
Connecting a Display
Before you can start using your Raspberry Pi, you’re going to need to connect a display. The Pi supports three different video
outputs: composite video, HDMI video and DSI video. Composite video and HDMI video are readily accessible to the end
user, as described in this section, while DSI video requires some specialised hardware.
Composite Video
Composite video, available via the yellow-and-silver port at the top of the Pi known as an RCA phono connector (see Figure 1-
2), is designed for connecting the Raspberry Pi to older display devices. As the name suggests, the connector creates a
composite of the colours found within an image—red, green and blue—and sends it down a single wire to the display device,
typically an old cathode-ray tube (CRT) TV.
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