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CDrom access via BIOS
Posted: Sun Feb 29, 2004 1:39 am
by mr. xsism
if i were to burn a 512byte bootsector to a CD rom how would i go about loading my kernel form the CD rom? How can i do it via BIOS?
What other ways besides BIOS are there that i could do in under 2KB?
Thanks :]
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 2:10 am
by FlashBurn
Maybe you are interested in my loader. It can load files from everywhere from the cd and at the moment it is 1,64kb small. But the code isn?t commented ::)
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Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 3:03 am
by mr. xsism
holy ow that's exactly what i needed. Now i just need to make some notes on the interrupt used and write a tutorial on it. WOW, where did u find that info? Ralpha Brown's list?
Thanks
--
i found some info this:
http://www.bitzenbytes.com/101/r115-int13.htm
so i guess DL is useful after all. From this lil tid bit i can now write a bootloader for hard drive, floppy drive, and cd rom. Thanks again!
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 8:04 am
by FlashBurn
There is a nice site and they have Ralph?s interrupt list in HTML. From there I get most of my information about the BIOS!
http://www.ctyme.com/rbrown.htm
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 9:37 am
by ASHLEY4
Hi
FlashBurn's code is a good bit of code.
But if you get any floppy disk that's bootable, and make a image of it, burn it to cd with easy burn or nero burn etc ,by burning it as a bootable.
Then the cd emulat's a floppy drive,Put's your real floppy drive from say A: to B: drive etc.
This work really good eg: no floppy clicking sound and it loads quicker.
I am making a 32bit atapi drive that that you can load from the floppy image and when you put the 1.44 floppy image on the cd ,With this diver you can load from the rest of the cd .eg: 600 mb ;D.
ASHLEY4.
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 10:39 am
by mr. xsism
So if i put my FAT12 image on a CD it will boot without moddification? Does this default on ALL systems? x86 anyway? Flashburn's code is still useful for ISO CD info.
Thanks
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 11:28 am
by FlashBurn
Maybe someone is interested in. If you modify the code a little bit so that the loader init the segment regs you can use it as a bootsector and load all of your files or just the kernel. The advantage of the cd is that you can load more than 1 sector by the BIOS.
Edit::
The reason why I didn?t want to use the floppy, is 1st the FAT filesystem, cause I?m understanding the cd filesystem much better than the FAT and 2nd can I have the same dir structure as on a harddisk
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 11:29 am
by ASHLEY4
mr. xsism wrote:
So if i put my FAT12 image on a CD it will boot without moddification? Does this default on ALL systems? x86 anyway? Flashburn's code is still useful for ISO CD info.
Thanks
Yes,Any bootable floppy,But the size is standard floppy size's.(eg: most will be 1.44mb)the pc is tricked into thing that its a floppy or HD etc.
You can also do the same with a bootable HD image.
And like i said Flashburn's code is very good.
You used to hand code it, But now the cd burning software does the hare work for you. ;D
ASHLEY4.
Re:CDrom access via BIOS
Posted: Sun Feb 29, 2004 11:47 am
by ASHLEY4
FlashBurn wrote:
Edit::
The reason why I didn?t want to use the floppy, is 1st the FAT filesystem, cause I?m understanding the cd filesystem much better than the FAT and 2nd can I have the same dir structure as on a harddisk
Flashburn you can do the same with a HD image.
I was going to use the iso 9660.
as a file sys, when i first started making a os.But i soon found that it was no good,(its a big compromize)
And you are going to need a atapi driver in your os any way. so Y not make it a the begining.
ASHLEY4.