Any concern about programming on Duo Core technology?

I just heard about Duo Core technology. It's about 2 cpus in one chip. Some say some applications running in single thread might run incorrectly with Duo Core cpu. Is that real? And any programming suggestion if we want to take advantages of Duo Core cpu?

Thanks : )

Single threaded applications will run correctly in a single core or multi-core CPU. It is the multi-threaded applications which may have problems on dual core CPU because 2 threads are really running concurrently, whereas in a single core CPU, technically only one thread is running at any given time. This problem can be solved by rewriting the synchronizing mechanisms.