@wook_sf,

ELF existed before ARM. It's used by most Linux/Unix operating systems, and is architecture-independent, meaning it can be used for x86, ARM, or whatever. Originally it was used for x86.

AFAIK Symbian used an ELF-like (or ELF-derived) format, but not quite ELF.

I'm not aware of any Windows (CE or not) versions using ELF natively. Windows (including CE) uses PE (portable executable).