[LinuxBIOS] Filo boot from CD-Rom syntax

[Russ Whitaker]

On Tue, 30 Jan 2007, Takeshi Sone wrote:

> On Tue, Jan 30, 2007 at 12:40:26AM -0800, Russ Whitaker wrote:
>> On Sun, 28 Jan 2007, roger wrote:
>>> Can somebody please update the Filo README file (and/or the Linuxbios
>>> Filo documentation) to including the following concerning CD-ROM device
>>> file syntax?
>>>
>>> ie. CD-ROM device is to be specified as "hdc1" and not "hdc"!
> <snip>
>> Personally I think that is a "bug" in FILO.
>
> No, this is not a bug.
>
>>    "hdx"   refers to the entire device "x"
>>    "hdx1"  refers to the first primary partition of "x"
>>    "hdx2"  refers to the second primary partition of "x"
>
> "hdb" refers to the entire CD-ROM.
> "hdb1" refers to the "boot disk image" in the CD-ROM.
>
> "Boot disk image" is something like 1.44MB floppy disk image, as
> specified in El Torito.

The "1" is misleading. It is not a partition. Perhaps it should have
been named "hdbi" or the like.

The El Torito spec says:
   "... int 41 is not valid on a CD-ROM."
      (int 41 reads/writes the partition table)

    Bios int 13 (low-level disc i/o) is used to fetch a "mode" from the CD:
       No Emulation Mode
       Drive A:  1.2
       Drive A:  1.44
       Drive A:  2.88
       Drive C:  hard drive

reference:
http://www.phoenix.com/NR/rdonlyres/98D3219C-9CC9-4DF5-B496-A286D893E36A/0/specscdrom.pdf

(Interesting read, and it's not very long - 19 pages and a blank page)

    Russ