how to build embedded linux system in embedded device

Linux is making steady progress in the embedded arena. Because Linux is covered under the GPL (see Resources later in this article), anyone interested in customizing Linux to his PDA, palmtop, or wearable device can download the kernel and applications freely from the Internet and begin porting or developing. Many Linux flavors cater to the embedded/realtime market. These include RTLinux (Real-Time Linux), uclinux (Linux for MMUless devices), Montavista Linux (Linux distributions for ARM, MIPS, PPC), ARM-Linux (Linux on ARM), and others (see Resources for links to these and other terms and products mentioned in this article).
Embedded Linux development broadly involves three tiers: the bootloader, the Linux kernel, and the graphical user interface (or GUI). In this article, we will focus on some basic concepts involving these three tiers; we will provide some insights into how the bootloader, kernel, and filesystem interact; and we will investigate some of the numerous options available for the filesystem, GUI, and bootloaders.
Bootloaders
The bootloader is usually the first piece of code that will be executed on any hardware. In conventional systems like desktops, the bootloader is normally loaded into the MBR (Master Boot Record), or the first sector of the disk where Linux resides. Normally, BIOS will transfer control to the bootloader in the case of desktops or other systems. This poses an interesting question: who loads the bootloader onto the embedded devices, which (in most cases) don't have BIOS?
Two general techniques are used to address this problem: specialized software and tiny bootcode.
Specialized software can directly interact with the flash device on the system remotely and install the bootloader at the given location in flash. Flash devices are special chips that act like storage devices, and they are persistent -- that is, the contents are not erased on reboot.

how to build embedded linux system in embedded device

what is Pervasive & Ubiquitous Computing video lecture with material

what is Pervasive & Ubiquitous Computing video lecture with material

[ebook]Building Embedded Linux Systems Ebook Download

By Karim Yaghmour

Publisher: O'Reilly Media

Released : April 2003

Pages:416

 

 

[ebook]Building Embedded Linux Systems Ebook Download

STARTING LINUX DAEMONS WITH init SCRIPTS

In the world of Linux based systems, and also other Unix-like systems, a daemon is a background process that starts during the system boot and runs forever. A daemon provides some kind of service. Some of the examples of daemons are the secure shell daemon sshd, and the print spooler, cupsd, formally known as the common unix printing system daemon.
In this tutorial, we first take a overview of the Linux boot sequence. We look at the traditional System V init process, the different init levels and the system of init scripts. Then, we look at upstart, which takes a different approach to the same job. Finally, we also look at the structure of a typical init script.

STARTING LINUX DAEMONS WITH init SCRIPTS

what is the Benefits of browsing the Linux source code ?? how to open linux kernel

Going through the Linux source code is like picking the technical nuances of Linux first hand. Without an iota of doubt Linux within it has all the concepts and skills that a system programmer needs, I figured this out the hard way. Programming excellence can be achieved through ripping the source apart and diagnosing it. Let me list you some direct benefits ushered by source code reading

First hand information

You can read from books, get information from the Internet or by other means but nothing like knowing it first hand by exploring the Linux source code. This rich treasure of GNU/C code has got everything that you are looking for. This information leaves absolutely no space for any doubts as this is the final original source of information and there are zero alternates to this. As you comprehend these pieces of code it’s like going through the minds of the people who have actually written it. And this experience and the kind of learning involved will never be found anywhere.

Improve your conceptual clarity

As you follow the flow of the code, the concepts get unfolded and the maze starts to show you the way. Personally I go through this process whenever I’m tied in two minds on a particular OS concept. It cuts down the need for looking for other sources; however this needs some real experience. If you do this exercise regularly then I’m sure cracking or understanding any technical concept, even though it is not related to an OS becomes a piece of cake for you

Efficient code writing style and skill

Just look and appreciate the style and standards followed by this open source marvel that has stood the time and taken the brunt of real time performance and emerged as the best open project ever. The coding standards are so defined and stable that all these varied pieces of code contributions from all over the world has never brought this thing down. So one thing that you undoubtedly get is the skill to code like a top class pro.

Rock solid confidence

This requires serious mention, when I first started off with the initial versions of the Linux kernel the best thing that I got was a truck load of confidence. This single benefit was the sole reason for all my success as a programmer and as a trainer. Lack of confidence can even hinder the growth of a technically sound individual. So get that confidence right now with some useful source code reading

Increased adaptability to change

If you digest the design and frameworks on which these operating systems are build and if you go back to the previous versions of Linux and track down the progression you will no doubt heighten your clarity and grip on the subject. You will also become most adaptable to future changes and you can even predict technological changes, which may often become real. So this skill will equip you with the flexibility and adaptability to changes

Final word

I for sure know that this is a small list of benefits that source code browsing can bring to you. If you have done this before then I request you to add on to this list of benefit through your valuable feedback

credits goes to Raghu Bhardwj 

what is the Benefits of browsing the Linux source code ?? how to open linux kernel

Friendly Arm Samsung S3c2440a

Friendly Arm Samsung S3c2440a

Friendly Arm Samsung S3c2440a

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