Question

How is a computer different from other machines

Answer 1

Primarily because it has a Central Processing Unit (CPU) and a sequence of instructions known as software or firmware (and an array of memory, too). The CPU is a general-purpose device that can do basic arithmetic, conditional, and data movement operations. By “conditional operations” I mean “if this is true, do that”. Other electronic devices are very fixed in their purpose and operation; they are designed to do only one thing. A computer is designed, in its most basic form, to do an arbitrary and even near-infinite array of things; all you have to do is change the software. (In practice some computers have fixed software and limited hardware to do one task, but in principle they can still do a variety of things.) It’s like the difference between a picture you draw which represents one concept, and an alphabet and corresponding language which can express an infinite number of ideas.