the difference between bz image and z image is in compression mode
not only compression mode
there are many differnces
A uImage file is a kernel with a modified header for u-boot. A tool called mkimage is used to convert a zImage (regular kernel compressed image) to a uImage file. And No, zImage files, as they are, are not compatible with U-Boot. You must convert them
make zImage - Creates a gzip’d kernel image that must be installed manually.
make bzImage - Creates a bzip2’d kernel image that must be installed manual
bz image is compressed image when compared to zimage
suggest me if any thing wrong
Showing posts with label linux kernel. Show all posts
Showing posts with label linux kernel. Show all posts
what is the difference between zimage bz image and u image
Wednesday, December 15, 2010
how to cross compile the kernel for ARM9 minin 2440 friendly arm mini 2440 for ubantu
In this tutorial, I'll quickly show you how easy it is to compile a kernel for the mini2440. If you haven't already installed git, you should do so now. In Ubuntu, you simply install the package git-core.
Setting up Your Toolchain
Follow the instructions from this tutorial.
http://chaitutechbits.blogspot.com/2010/12/how-build-arm9-tool-chain-mini-2440.html
Obtaining the Correct Kernel Sources
In order for you to get a kernel thats patched for all the hardware on your Mini2440, you need to get the kernel sources from the correct place. While it's possible to simply go and download a kernel directly from kernel.org and cross compile it, you won't get the patches included with that for all the hardware on the Mini2440.
Create a directory for your source tree and change to it and use git to clone the repository.
Setting up Your Toolchain
Follow the instructions from this tutorial.
http://chaitutechbits.blogspot.com/2010/12/how-build-arm9-tool-chain-mini-2440.html
Obtaining the Correct Kernel Sources
In order for you to get a kernel thats patched for all the hardware on your Mini2440, you need to get the kernel sources from the correct place. While it's possible to simply go and download a kernel directly from kernel.org and cross compile it, you won't get the patches included with that for all the hardware on the Mini2440.
Create a directory for your source tree and change to it and use git to clone the repository.
Code:
$ mkdir mini2440-kernel
$ git clone git://repo.or.cz/linux-2.6/mini2440.git
$ cd mini2440
$ git clone git://repo.or.cz/linux-2.6/mini2440.git
$ cd mini2440
how build arm9 tool chain ?? for mini 2440 friendly arm micro 2440
This howto will show you how to quickly and easily set up an ARM toolchain so that you can use openembedded. You can also use this toolchain to compile the linux kernel or anything else that you specifically want to compile for the mini2440.
Download the toolchain here.
After you've downloaded the toolchain, you can untar it into your /usr/local directory or somewhere in your home directory if you don't have root access to the machine you're compiling on.
how to compile u boot for arm9 friendly arm mini 2440 micro 2440 ?? what is uboot
UBoot must usually be installed in a Flash memory to be
executed by the hardware. Depending on the hardware, the installation of UBoot
is done in a different way
The board provides some kind of specific boot monitor, which allows to flash the second stage bootloader. In this case, refer to the board documentation and tools UBoot is already installed, and can be used to Flash a new version of UBoot.
However, be careful: if the new version of UBoot doesn't work, the board is unusable
The board provides a JTAG interface, which allows to write to the
Flash memory remotely, without any system running on the board. It
also allows to rescue a board if the boot loader doesn't work.
The bootloader that comes factory installed on the Micro2440 and the Mini2440 board is called Supervivi. I don't personally like it. It has very limited support and requires a YAFFS filesystem for the root filesystem. So when I bought my board I began to immediately search out an alternative. The bootloader by choice, it seems, is a modified version of U-Boot with modifications for the Mini2440 board's hardware
The code is maintained by a guy named buserror. I'll provide his information at the end of this howto.At the time of writing this, I had some issues with getting Buserror's U-Boot working correctly.
The code that is in his git repository, doesn't run from RAM without a modification to the source. So here are the instructions that I gathered for altering and compiling it, and getting it going on the Mini2440 and Micro2440 board.
For this to work, I'm going to assume that you have a crosscompiler set up. Later on, I will probably write an entry here about setting that up, but not now. I'm also assuming you have git installed.
Step 1: Get the source
mkdir uboot ;
cd uboot git clone git://repo.or.cz/u-boot-openmoko/mini2440.git
Step 2: Set your cross compiler prefix so you don't end up compiling this for x86.
export CROSS_COMPILE=arm-none-linux-gnueabi-
[ebook]Building Embedded Linux Systems Ebook Download
- By Karim Yaghmour
- Publisher: O'Reilly Media
- Released : April 2003
- Pages:416
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.
Embedded Linux Boot- Code Walkthrough
Embedded Linux on Arm:
———————————-
We will walk through boot up code for AT91RM9200 system-on-chip, built around the ARM920T ARM Thumb processor. Kwickbyte builds an embedded board called kb9202 based on AT91RM9200.
Before you start reading this you need to read AT91RM9200 data sheet (specification). You can download the data sheet with the following link.
www.keil.com/dd/docs/datashts/atmel/at91rm9200_ds.pdf
You also need to read ARM Architecture Reference Manual for better understanding the boot process. You can download it with the following link.
http://www.lysator.liu.se/~kjell-e/embedded/ARM-ARM.pdf
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
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
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