[syslinux] Fair warning regarding the future of the COM32 format

H. Peter Anvin hpa at zytor.com
Wed Aug 30 17:11:10 PDT 2006

Hi all,

I just want to give everyone a heads-up that I'm considering removing 
support for COM32 in favour of relocatable (-fPIC) ELF files, or some 
other relocatable format.  This would allow one "ELFCOM" file to call 
out to another, and then return.

Part of the idea here is to run the main syslinux UI and probably the 
filesystem drivers in "ELFCOM" code, which doesn't work too well with 
everything being statically linked to a fixed address.

The other option, which I am also considering, is to do the same thing 
by playing games with segments.  This would break COM32 files which rely 
on touching fixed addresses (which most of them currently do), but would 
otherwise be a relatively straightforward operation.  If I do that, I'll 
  introduce a standard GDT which would have flat segments as well as 
fixed-offset ones, but you'd still have to convert pointers before 
passing them to something.  It's not clear to me at this time which way 
is better, although I think I am leaning toward the former.


More information about the Syslinux mailing list