What is Module.symversion used?

[Durga Prasad]

Hello, 

When compiling a kernel module, i see a Module.symvers missing message, like:

  WARNING: Symbol version dump 
/usr/src/linux-2.6.27.19-5-obj/ia64/debug/Module.symvers
           is 
missing; modules will have no dependencies and modversions.

What is Module.symvers used for? What happens if you ignore this warning? 

Thanks
Durga