As I understand, the concept 'computation' started dependent on hardware (like looms for instance). The Hardware defines (physical cascades) what happens between input and output. I think I saw in a CS class, a mention about universal calculation where software is not limited by hardware? It's hard to find a succint answer. What makes a universal calculator, universal? (I'm not a CS major, so forgive my unprofessional terms and wordings)Thank you.  
How does universal calculator work?
computation models;turing completeness