Operation Manual

Chapter 1: Meet the Raspberry Pi
Your Raspberry Pi board is a miniature marvel, packing considerable computing power into a footprint no larger than a credit
card. It’s capable of some amazing things, but there are a few things you’re going to need to know before you plunge head-first
into the bramble patch.
If you’re eager to get started, skip ahead a couple of pages to find out how to connect your Raspberry Pi to a display, keyboard and mouse.
ARM vs. x86
The processor at the heart of the Raspberry Pi system is a Broadcom BCM2835 system-on-chip (SoC) multimedia processor.
This means that the vast majority of the system’s components, including its central and graphics processing units along with the
audio and communications hardware, are built onto that single component hidden beneath the 256 MB memory chip at the
centre of the board (see Figure 1-1).
It’s not just this SoC design that makes the BCM2835 different to the processor found in your desktop or laptop, however. It
also uses a different instruction set architecture (ISA), known as ARM.
Figure 1-1: The BCM2835 SoC, located beneath a Hynix memory chip
Developed by Acorn Computers back in the late 1980s, the ARM architecture is a relatively uncommon sight in the desktop
world. Where it excels, however, is in mobile devices: the phone in your pocket almost certainly has at least one ARM-based
processing core hidden away inside. Its combination of a simple reduced instruction set (RISC) architecture and low power
draw make it the perfect choice over desktop chips with high power demands and complex instruction set (CISC) architectures.
The ARM-based BCM2835 is the secret of how the Raspberry Pi is able to operate on just the 5V 1A power supply provided
by the onboard micro-USB port. It’s also the reason why you won’t find any heat-sinks on the device: the chip’s low power
draw directly translates into very little waste heat, even during complicated processing tasks.
It does, however, mean that the Raspberry Pi isn’t compatible with traditional PC software. The majority of software for
desktops and laptops is built with the x86 instruction set architecture in mind, as found in processors from the likes of AMD,
Intel and VIA. As a result, it won’t run on the ARM-based Raspberry Pi.
The BCM2835 uses a generation of ARM’s processor design known as ARM11, which in turn is designed around a version of
the instruction set architecture known as ARMv6. This is worth remembering: ARMv6 is a lightweight and powerful architecture,
but has a rival in the more advanced ARMv7 architecture used by the ARM Cortex family of processors. Software developed