[syslinux] memdisk fails with 4 hdds

[H. Peter Anvin]

Knut Petersen wrote:
> 
> This bug is definitely not related to the Award 4.51PG/6.0PG
> el-torito/noemul/nohdds bug. As I´m the man that sent you that "sick, 
> sick, sick"
> hack [-hpa in december 2002] you decided not to integrate into isolinux,
> I feel qualified to give this diagnosis.  [off topic on:] A quick search 
> with
> google gave lots of complaints about isolinux on those systems. As Award
> is unwilling to fix the bug for at least 7 years, wouln´t it be a good 
> idea to
> integrate the workaround in isolinux? [off topic off]
> 

I'm a bit nervous, since I don't have any chance to test it myself.  As 
it falls in the "sick and brilliant" category, it makes me nervous, and 
I can also recognize the value of it :-/

> All this leads me to suspect that there is some kind of bug in the 13h isr
> of memdisk. Do you have an extended memdisk-debug version that shows
> exactly the parameters and return values of the int 13 calls?

I don't; I tend to debug it in emulation, but that doesn't work if it's 
a specific BIOS that triggers the bug.

> Is there anybody reading this list who can confirm that a pxelinux/memdisk
> DOS boot works (or not) on his system with 4 hdds installed?

I can try it tomorrow; I have a machine which I think have 4 
BIOS-visible hard drives.

	-hpa