Question: what is the difference between ios and ios xr?
Answer: Differences between IOS and IOS XE On the other hand, IOS XR is based on QNX (since version 5.0 it's also based on linux) where the IOSd application has been separated into many different applications. While IOS XE (IOSd) and IOS share a lot of the same code, IOS XR is a completely different code base.