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Bootable CD
Posted: Thu Sep 06, 2007 8:40 am
by ezome
Does anyone know a good tutorial about this topic?
-whats the filesystem on a cd?
-access from real mode (bootloader)
-access from protected mode (c kernel)
Re: Bootable CD
Posted: Thu Sep 06, 2007 9:48 am
by Candy
ezome wrote:Does anyone know a good tutorial about this topic?
-whats the filesystem on a cd?
ISO9660 (wikipedia), with El Torito bootloading extensions (also wikipedia, most likely a few OSdev websites, a few threads here)
-access from real mode (bootloader)
Depending on the emulation, whatever it emulates or a plain IDE CDROM drive.
-access from protected mode (c kernel)
IDE ATAPI drive, SATA ATAPI drive, whatever else it is? Try the PCI IDE documents, Hale Landis' driver, AHCI documentation...
Re: Bootable CD
Posted: Thu Sep 06, 2007 9:57 am
by ezome
Candy wrote:Depending on the emulation, whatever it emulates or a plain IDE CDROM drive.
whats the most common way a boot cd is accessed from real mode today?
how do the linux/windows boot cds do it?
Re: Bootable CD
Posted: Thu Sep 06, 2007 10:12 am
by Brynet-Inc
ezome wrote:Candy wrote:Depending on the emulation, whatever it emulates or a plain IDE CDROM drive.
whats the most common way a boot cd is accessed from real mode today?
how do the linux/windows boot cds do it?
When the El Torito standard was in its infancy, It was common for bootable CD's to emulate a Floppy or Hard Disk Drive.
These days, most systems are fully capable of supporting "native" CD-ROM booting without the need of emulation.
Accessing the contents of the CD-ROM drive is something you'll have to read up on yourself..
http://en.wikipedia.org/wiki/ISO9660
http://en.wikipedia.org/wiki/El_Torito_ ... tandard%29
Posted: Thu Sep 06, 2007 1:02 pm
by Dex
Its simple you take a bootable floppy image and use that to make a CD bootable.
Most burn software have a opion (something like make bootable) click on it, and it will ask for a bootable floppy image or Hdd or you can point it to a floppy drive with a bootable floppy in it.
What ever way you use, once you point it to a .img it will add 2 .bin file to the CD image, you can then add more stuff, but unless you make a ATAPI driver you can only get at whats in the image.
Now remember emulation only works in realmode, so you need to load the stuff from the image to below 1 MB than move it on or go to and from pmode to realmode to load stuff.
I use this floppy emulation even though i have a ATAPI driver.
Posted: Thu Sep 06, 2007 1:19 pm
by ezome
ok thanks for the info guys
ill try that