Into how many major types can general-purpose computers be classified?

General-purpose computers are traditionally classified according to how they process data, into three major types:

• Analog computers, which process continuously varying physical quantities (such as voltage, temperature, or pressure) rather than discrete numbers.
• Digital computers, which process data represented as discrete binary digits (0s and 1s); this is the type used in almost all modern desktops, laptops, and mobile devices.
• Hybrid computers, which combine both analog and digital processing techniques, commonly used in specialised scientific and medical equipment.

This three-way classification, based on the mode of data processing, is the standard one taught at this level, so the correct number of major types is three, not four, five, or six.

Examination reminder: keep this classification (analog, digital, hybrid) separate from a classification by size or capacity (supercomputer, mainframe, minicomputer, microcomputer), which is a different, size-based scheme with its own number of categories.