GUF-Yocto-jethro-9.0-r7707-0
i.MX6
User Manual
2
Overview
A Garz & Fricke Linux System generally consists of four basic components:
the bootloader
the Linux kernel
the root file system
the device configuration
These software components are usually installed on separate partitions on the backing storage of the embedded
system.
Newer Garz & Fricke devices are shipped with a separate small ramdisk-based Linux system called
Flash-N-Go
System
which is installed in parallel to the main operating system. The purpose of Flash-N-Go is to provide the
user a comfortable and secure update mechanism for the main operating system components.
2.1
The bootloader
There are several bootloaders available for the various Linux platforms in the big Linux world. For desktop PC
Linux systems, GRUB or LILO are commonly used. Those bootloaders are started by hardwired PC-BIOS.
Embedded Systems do not have a PC-like BIOS. In most cases they are started from raw flash memory or an
eMMC device. For this purpose, there are certain open source boot loaders available, like RedBoot, U-Boot or
Barebox. Furthermore, Garz & Fricke provides its own bootloader called
Flash-N-Go Boot
for its newer platforms
(e.g. SANTARO).
i.MX6 uses the bootloader
Flash-N-Go Boot
.
2.2
The Linux kernel
The Linux OS kernel includes the micro kernel specific parts of the Linux OS and several internal device and
subsystem drivers.
2.3
The root file system
The root file system is simply a file system. It contains the Linux file system hierarchy folders and files. Depending
on the system configuration, the root file system may contain:
system configuration files
shared runtime libraries
dynamic device and subsystem drivers - so called
loadable kernel modules
- in contrast to kernel-included
device and subsystem drivers
executable programs for system handling
fonts
etc.
Usually, a certain standard set of runtime libraries can be found in almost every Linux system, including standard
C/C++ runtime libraries, math support libraries, threading support libraries, etc.
Embedded Linux systems principally differ in dealing with the graphical user interface (GUI). The following list
gives some examples for GUI systems that are commonly used in embedded Linux systems:
no GUI framework
Qt Embedded on top of a Linux frame buffer device
Qt Embedded on top of DirectFB graphics acceleration library
Qt Embedded on top of an X-Server
GTK+ on top of DirectFB graphics acceleration library
GTK+ on top of a X-Server
Nano-X / Microwindows on top of a Linux frame buffer device
Some system may additionally be equipped with a window manager of small footprint or a desktop system like
KDE ore GNOME. However, in practice most embedded Linux Systems are running only one GUI application and
a desktop system generates useless overhead.
i.MX6 is equipped with
Qt5 on top of a X-Server
.
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