Syslinux - Apr 2002 - isolinux puzzle

Peter,

Thank you for isolinux. What a relief to be rid of floppy images! 

ISOLINUX works great except in one puzzling instance.

I recently upgraded my system with a Promise Ultra 133 (PDC20269)
controller. In order to boot from either the hard drive or CDROM drive
connected to this controller I set the boot device in the motherboard
BIOS to SCSI. Everything seemingly works great.

Until we get to Linux boot CDs. :-(

In testing CD booting via the Promise controller I discovered that stock
Linux boot CDs such as the RedHat install CDs are not recognized as
bootable by the Promise BIOS. However, the Windows 2000 install CD (no
emulation) is indeed recognized as bootable.

Aha I thought, this must be a problem with floppy emulation. So I
searched the Internet for a "no emulation" boot loader solution and
found ISOLINUX which I was sure would solve the problem. 

And it does work on all other CDROM drives except the one attached to
the Promise controller. I'm really baffled. Why is the WIN2K CD
recognized as bootable, but not the Linux CD created with ISOLINUX? 

I followed your web page ISOLINUX instructions to the letter and as I
mentioned above the CD does boot on other CDROM drives. I'm willing to
roll up my sleeves and do some research, but I'm not sure how to
proceed. I suspect you may have an idea of what the problem area could
be or at least how to go about zeroing in on a solution in the most
efficient way. I am a veteran developer and have previously created
bootable Linux CDs using syslinux, but don't have the expertise to size
up this problem. Any pointers/suggestions would be greatly appreciated.
Thanks.

Regards,

Peter Stein

Peter Stein wrote:
> 
> And it does work on all other CDROM drives except the one attached to
> the Promise controller. I'm really baffled. Why is the WIN2K CD
> recognized as bootable, but not the Linux CD created with ISOLINUX? 
> 
Probably because it's the only one they ever tried, and their BIOS is so 
broken that it's the only thing they'll ever boot.

ISOLINUX actually spends a lot of effort at being similar to the Win2K 
boot, just because too many BIOSes just don't give a shit about anything 
else.  Unfortunately, seems yours is still not happy.
> I followed your web page ISOLINUX instructions to the letter and as I
> mentioned above the CD does boot on other CDROM drives. I'm willing to
> roll up my sleeves and do some research, but I'm not sure how to
> proceed. I suspect you may have an idea of what the problem area could
> be or at least how to go about zeroing in on a solution in the most
> efficient way. I am a veteran developer and have previously created
> bootable Linux CDs using syslinux, but don't have the expertise to size
> up this problem. Any pointers/suggestions would be greatly appreciated.
I suspect the BIOS is buggy as hell and can only boot something that 
looks more-or-less exactly like the Win2K CD.  What exactly it is that 
trips it up is nearly impossible to tell without having both CDs and 
access to the system.

	-hpa