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can bios boot a system?
Posted: Fri May 09, 2003 10:37 pm
by yan
hi,sirs
i wonder that if bios can boot a system.
sometimes we could write bios using softwares,now if we try to change the exit,can we run our systems?
Re:can bios boot a system?
Posted: Sat May 10, 2003 7:02 am
by Pype.Clicker
sorry , i don't get your point ... could you rephrase ?
Re:can bios boot a system?
Posted: Sat May 10, 2003 2:10 pm
by udarkman
I think changing the code of bios to boot is theoretically possible.
As we know, in startup procedure, bios does lots of tests and those are done according to the software in ROM(and resently in flash roms). If you change the code in flash ROM with using special software, I think it may be possible to use bios to boot a system.But what could be the reason using bios for a boot loader?
Re:can bios boot a system?
Posted: Sat May 10, 2003 7:43 pm
by yan
yes sir,you r right!
you know,floppy drive will be taken by usb,and isn't it a trouble thing to boot from it?now if we could boot skipping floppy drive,we will not listen to noisy it makes and slow speed it lead to.
what we should do is to put the exit(opposite entrance)which point to start floppy drive to the boot program.
Re:can bios boot a system?
Posted: Sun May 11, 2003 2:00 am
by beyond infinity lazy
Like OpenBootProm or similar (MacIntosch'es used to keep part of the os in the Prom: the very low level structures of it)?
But Bios does this already, what you say: it searches for a device to boot a system from and then kicks it on.tzhis is the bios' task, nothing more.
why you rant about floppy I don't understand.
Re:can bios boot a system?
Posted: Sun May 11, 2003 6:13 am
by yan
Maybe i need some knowledge about BIOS,and talk later.
is there anything for program in Bios?
Re:can bios boot a system?
Posted: Sun May 11, 2003 9:49 am
by bgcq
there have a few stuff of bios-seg ::)
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Re:can bios boot a system?
Posted: Sun May 11, 2003 8:55 pm
by Pinczakko
I've implement one, it works. Unfortunately, right now still in real mode (the protected mode setup stuff still buggy). I'm using a PCI PnP Option ROM on my LAN Card, it works this way: The whole OS is in an Atmel 64 KB Flashrom located in the Lan Card, when booting (during int 19h) I trap it using BEV (bootstrap entry vector) mechanism (explained in PnP bios spec. version 1.0A and PCI spec 2.2 and Bios Boot Spec by Intel and Phoenix ), then I load my OS from the ROM into RAM, but this stuff is still obscured on how it really works since I can't find any docs that explain how it really implemented, but it's working. Then I jum into my OS code in RAM and execute it there, this technique can be extended as we wish. That's all I know
