Hardware Reference
In-Depth Information
he most popular operating system for the Raspberry Pi is Linux. he widescale use of
Linux (just think how many Raspberry Pis there are, not to mention Android phones, web
servers, and so on) shows how much an idea can grow. After you start tinkering with the
Raspberry Pi, one of your ideas might grow to be as big (or bigger) than Torvalds's or those of
the founders of the Raspberry Pi, and you too will make a real impact on the world. So let's
get started!
Getting the OS on an SD Card
he Raspberry Pi doesn't know how to coordinate its hardware without an OS. When it is
powered up, it looks on the SD card to start loading the OS. As such, you're going to need an
SD card with an OS on it.
You can either buy an SD card that already has an OS on it, or you can copy an OS to your
own SD card with a PC. A premade card is simplest, but more expensive. Creating your own
isn't too diicult, but it is slightly more involved than just copying a ile.
Premade Cards
Premade cards are bundled in kits or available to purchase from element14, RS or
other online stores. A 4GB card should be big enough for getting started and cost less
than £10.
Filesystems
Computer storage like SD cards, USB memory sticks and hard disks essentially contain mil-
lions of separate compartments that store small amounts of data in large grids. The indi-
vidual compartments, called
blocks,
are addressed by a coordinate system - you can think
of them as a piece of squared paper the size of a sports ield. The sports ield is partitioned
into areas of blocks that are handled by the operating system to provide
ilesystems.
It is
the OS's job to manage how data is written to this massive storage area, so that when a
user refers to a ile by name, all the tiny blocks of data are fetched and combined in the cor-
rect order. There are different ways in which the blocks are formatted, with different fea-
tures. As such, an identical ile will be stored differently on the underlying grid by different
ilesystems.
Typically, Microsoft Windows uses FAT or NTFS, OS X uses HFS Plus and Linux uses ext.
Most blank SD cards are formatted as FAT by default. Because the Raspberry Pi runs Linux,
it uses the ext ilesystem, which must be set up and populated with iles.
