It is hard to imagine that a spacecraft with a computer that has a fraction of the computing power of a modern smartphone was able to successfully get men to the moon and back in the late 1960's and 1970's. 

However there were actually 4 computers controlling the Apollo spacecraft and they had no GUI's or touch screens to waste their resources on. 

These computers were specialized for their tasks and therefore they did what they were programmed to very well, so it is hard to compare them with modern computers. 

The redundancy was built into the software itself and was designed to keep mission critical programs running, even during failures. 

Check out the interesting video below to learn more and don't forget to leave a comment and let me know what you think!