Hardware Reference
In-Depth Information
❍
media
—his is a special directory for removable storage devices, like USB memory
sticks or external CD drives.
❍
mnt—
his folder is used to manually
mount
storage devices, such as external hard
drives.
❍
opt—
his stores optional software that is not part of the operating system itself. If
you install new software to your Pi, it will usually go here.
❍
proc
—his is another virtual directory, containing information about running pro-
grams which are known in Linux as
processes
.
❍
selinux
—Files related to
Security Enhanced Linux
, a suite of security utilities originally
developed by the US National Security Agency.
❍
sbin
—his stores special binary iles, primarily used by the root (superuser) account
for system maintenance.
❍
sys
—his directory is where special operating system iles are stored.
❍
tmp
—Temporary iles are stored here automatically.
❍
usr
—his directory provides storage for user-accessible programs.
❍
var
—his is a virtual directory that programs use to store changing values or
variables
.
Physical Layout
Although the preceding list is how the ile system appears to the Linux operating system, it's
not how it's laid out on the SD card itself. For the default Debian distribution, the SD card is
organised into two main sections, known as
partitions
because they split the device into dif-
ferent areas in much the same way as the chapters of this topic help to organise its contents.
he irst partition on the disk is a small (75 MB) partition formatted as VFAT, the same par-
tition format used by Microsoft Windows for removable drives. his is
mounted
, or
made
accessible, by Linux in the
/boot
directory and contains all the iles required to conigure
the Raspberry Pi and to load Linux itself.
he second partition is far larger and formatted as EXT4, a native Linux ile system designed
for high-speed access and data safety. his partition contains the main chunk of the distribu-
tion. All the programs, the desktop, the users' iles and any software that you install yourself
are stored here. his takes up the bulk of the SD card.
