Difference between xtd and xsd files

Hi,
After performing dynamics in discover module, I want to perform shear using a script in forcite. From the output  in dynamics I can see .inp and .xtd files but not .xsd file. So, I exported the .xtd file to .xsd and performed the simulation.
Will the forces that I have given during dynamics run  regains in the .xsd file that which I performed simulation?
What is the actual difference between .xtd and .xsd files?  (I'm using Materials Studio 7 version)
Thank you