EDD error RE: [syslinux] Re: SYSLINUX 2.12-pre7 released

[H. Peter Anvin]

Blaauw,Bernd B. wrote:
> (Sorry, Outlook webmail prohibits me from proper replying/quoting)
> 
> 
>>it has the nice effect that you can load the El Torito 
>>CD-ROM driver.
> 
> 
> Which seems logical if you boot a kernel (like Linux, or Memdisk with an imagefile), but not when doing a local boot (diskette/harddisk)
> In other words: boot from cdrom, and if you then load a disk-image, eltorito.sys should load. If not loading a kernel or disk-image (but booting C: for example, or A:), then, IMHO, eltorito.sys should not be able to load (as the user opted to chainload instead of continuing to boot from cdrom).
> I wish I could provide an ISO or diskimage, but the 'bios EDD error' only occurs on MSDOS (IO.SYS) kernel, so I can't spread/provide that disk image.
> I'll manage, though. It's just making my testing a tiny bit more difficult (hit ESC each time the machine boots, then select floppy, instead of let isolinux boot and then select 'A' for localboot 0x80 as defined in my isolinux.cfg file)
> 
> UDMA2 author mailed this:
> ------------
> and avoids addressing over 20 bits.   Re: the "Int 13h" function codes used
> by UDMA2, they are (A) 41h to see if an EDD BIOS is present, 48h to request
> EDD parameters for every disk and 08h to request CHS values for every disk.
> All are "basic" functions that any (good) EDD BIOS should support.   If, in 
> 

The way the El Torito CD-ROM is going to look like to the program, is 
that it looks like an additional hard disk which a very high drive 
number (typically 9Fh or so); MS-DOS will normally ignore this since it 
asks the BIOS how many drives there are and ignores the rest.

Does the error message come from UDMA2.SYS or...?

	-hpa