boot from an ide

[Gin Lin]

I use FILO as the payload to boot from a Hard Disk, which has a installed 
linux on it. I noticed if I enabled the ide stream. It tries to read the ELF 
header from my IDE drive. But I thought the FILO payload should be the one 
to load the image from the IDE drive. When does it come in and play the 
role? Anyone can explain the flow of booting if I try to load the INSTALLED 
linux from a IDE drive.

Gin