Re: grub> ls doesn't show CDROM device

[Jordan Uggla]

On Sat, Oct 29, 2011 at 1:09 AM, Robert <address@hidden> wrote:
> v1.98
>
> Hello, on a very old system I boot e.g. from floppy then want to load linux
> kernel&image from (normal internal IDE) CDROM, then mount a Firewire disk
> paritition as root.
>
> (There seems to be no Firewire mod in Grub2? (and: the usbms,uhci,ohci mods
> also seem to not work correctly?))
>
> Yet "ls" on the grub prompt only shows the (fd0) boot device and an internal
> harddisks, if existing.
> The CDROM device is not visible.
> The iso9660 module is loaded.
> Which modules or ... do I need to see the CDROM from Grub2?
>
> and optionally: how to see USB keys, when not supported by Bios. (tried
>  insmod's:  usb usbms uhci ohci )
>
>
> PS: Yet if I boot e.g. from a super grub disk CD, I see the CDROM as (hd31)
> - and (fd0) also.  why not when booting from any other device?

By default grub only accesses drives through firmware interfaces, not
by accessing hardware directly. Most BIOSs, for whatever reason, only
present a CD drive to bootloaders when the machine was actually booted
from said CD drive. You can work around this by using native grub
drivers. For your IDE CDROM drive and grub 1.98 you would "insmod ata"
to be able to access your CDROM drive. For anything other than ATA you
really need to use grub 1.99 or newer.

-- 
Jordan Uggla (Jordan_U on irc.freenode.net)