What distinguishes a personal computer from a mainframe?

A personal computer (PC) and a mainframe differ significantly in terms of size and user access. Personal computers are designed for individual users, typically used in homes or offices for tasks like browsing the internet, word processing, and gaming. They are compact and portable, often fitting on a desk or even in a laptop form.

In contrast, mainframes are large, powerful machines designed for processing vast amounts of data. They are built to handle numerous simultaneous users and can support thousands of transactions per second. Mainframes are used in environments where reliability, availability, and security are imperative, such as in banking systems, government, and large corporations. The architecture of a mainframe allows for multiple users to access the system concurrently through terminals or remote connections, showcasing its capacity to handle heavy workloads efficiently.

This significant difference in user access capability, with mainframes catering to multiple users and demanding, high-volume tasks, while PCs focus on individual use, clearly distinguishes the two types of computers. Hence, the difference in size and user access is the key factor that sets personal computers apart from mainframes.