What distinguishes first generation computers?

First generation computers are distinguished by their use of vacuum tubes and electromechanical switches for processing information. This technology was foundational in early computer design and allowed for the manipulation of data in a way that hadn't been possible before. The reliance on these components meant that first generation computers were large, consumed a significant amount of electricity, and produced considerable heat, which necessitated special cooling systems.

While other options mention characteristics such as utilizing software, running on microprocessors, or processing text files, these features are not traits of first generation computers. The development of software was still in its infancy during this era, microprocessors emerged in later generations, and text file processing became more commonplace with subsequent advancements in computing technology. Thus, the defining characteristic of first generation computers being the use of electric motors and electromechanical switches highlights their role in the evolution of computing hardware.