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Where to get info about boot loaders?

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raj_rohit10

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hi
I wm new to this field and want to understand boot loader.Can someone provide me the pointer to resource for that
thanking you in advance.
rohit
 

Boot loader

What is a bootloader? then I think that the boot loader is a program which is executed after the execution of the code in BIOS is finished.
What is the task of this program? it should find where is the kernel of the operating system is located and then it should load the kernel plus needed related files into memory and then it should pass the program counter to the kernel.
Example: The really powerful Syslinux bootload is capable of booting your linux based machine from different kind of locations. From a simple hard drive to a usb stick. Please note that the kernel may reside some where on the local area network and your embedded system ( mainly your boot loader ) should read the kernel from network.
have a look at the documentation of dhcp in linux for this issue.
Test syslinux. it is really a greate tool to boot your system in hard conditions.
 

Re: Boot loader

raj_rohit10,

You will have to tell us what type of system you are using to post links to what you want.
Generally a bootloader is used in a FLASH UC. It is a program that (usually)resides at the end of flash memory and is invoked to download a hex program to the flash.
How it normally works (because it is implemented in many different ways) is that in the first couple of instructions in flash is a jump to the bootloader. The bootloader then checks if you want to downlaod a file or not (implememted in many differnet ways from checking if a charactor is recieved on com port to a button press). If a file is to be downloaded, it will work the comms (RS232, I2C, SPI, etc) to recieve the file, and will burn the file to the flash (usually leaving the jump to bootloader at start untoutched).
If no file is to be programed the bootlader will then jump back to the start of memory and start exacuting as normal.

here is a link to an excelent free PIC bootlader.

h**p://www.etc.ugal.ro/cchiculita/software/picbootloader.htm


Hope that helped

Maui
 

Boot loader

the flas programming is just one way, in one group of processors. I usually use DSPs, and they use the bootloader, to copy the program data from flash to the internal, or maybe to an external fast RAM memory. There, the flash programming is another thing.
I think the ARMs use the same method.
there are 2 types: simple auto copy the data from the source (flash), and an more intelligent type: you can handle and control these with linux-like commands, from your PC, to boot, or to program the flash, from serial port. The first type: like TMS... DSPs bootloader in their ROM, and the second: like the Uboot, for ARM, and Blackfin.
 

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