Payloads: Difference between revisions
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LinuxBIOS in itself is "only" minimal code for initializing a | LinuxBIOS in itself is "only" minimal code for initializing a | ||
mainboard with peripherals just enough for a Linux kernel to take | mainboard with peripherals just enough for a Linux kernel to take | ||
over and | over and do the rest. LinuxBIOS does not contain a kernel per se. | ||
After the initialization, LinuxBIOS jumps to a payload and while | After the initialization, LinuxBIOS jumps to a '''payload''' and while | ||
there has been discussion about stacking payloads that's currently | there has been discussion about stacking payloads that's currently | ||
not in practice. | not in practice. | ||
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ROM room for a kernel. 512KB can be seen here-and-there and a few | ROM room for a kernel. 512KB can be seen here-and-there and a few | ||
boards come with 1MB. Recent kernels really want that MB, and then | boards come with 1MB. Recent kernels really want that MB, and then | ||
you'll only have room for | you'll only have room for 300-400 KB of initial ramdisk, which could | ||
be too small too, depending on the application. | be too small too, depending on the application. | ||
So, other payloads are used; the two major ones are FILO and | So, other payloads are used; the two major ones are [[FILO]] and | ||
Etherboot. FILO loads a kernel from a filesystem on an IDE device and | [[Etherboot]]. FILO loads a kernel from a filesystem on an IDE device and | ||
Etherboot loads a kernel from the network or from a filesystem on an | Etherboot loads a kernel from the network or from a filesystem on an | ||
IDE device. | IDE device. | ||
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root and init commandline so that it can start init. | root and init commandline so that it can start init. | ||
== Possible Payloads == | |||
[[Etherboot]] | * [[Etherboot]] — Includes FILO, and its FILO supports SATA and USB booting. | ||
* [[FILO]] — Simple bootloader with filesystem support. | |||
[[FILO]] | * [http://www.openbios.org/ OpenBIOS] — IEEE1275-1994 Open Firmware | ||
* [[ADLO]] — Glue layer to 16-bit Bochs BIOS. Allows booting Windows. | |||
[http://www.openbios.org/ OpenBIOS] | * [[memtest86]] — Can stress-test your RAM. | ||
[[ADLO]] | |||
Revision as of 14:31, 5 October 2006
LinuxBIOS in itself is "only" minimal code for initializing a mainboard with peripherals just enough for a Linux kernel to take over and do the rest. LinuxBIOS does not contain a kernel per se.
After the initialization, LinuxBIOS jumps to a payload and while there has been discussion about stacking payloads that's currently not in practice.
The payload was originally intended to be a Linux kernel stored in flash. Flash ROM growth rate was anticipated optimistically however, today there are not many mainboards that actually have enough flash ROM room for a kernel. 512KB can be seen here-and-there and a few boards come with 1MB. Recent kernels really want that MB, and then you'll only have room for 300-400 KB of initial ramdisk, which could be too small too, depending on the application.
So, other payloads are used; the two major ones are FILO and Etherboot. FILO loads a kernel from a filesystem on an IDE device and Etherboot loads a kernel from the network or from a filesystem on an IDE device.
If you're using FILO there is no Linux kernel until FILO loads it, and the kernel loaded by FILO (or Etherboot) can absolutely be the one you want to run in your system. Just set it up with the correct root and init commandline so that it can start init.