Final answer:
Grid computing differs from multiprocessing and parallel processing as it relies on a collective of distributed computers working jointly, while the others refer to multi-core usage within one system or supercomputers.
Step-by-step explanation:
A key difference between grid computing, multiprocessing, and parallel processing is that grid computing relies on a community of computers acting together. Unlike grid computing, which can utilize a wide range of computers over a long distance, multiprocessing refers to a computer using multiple CPU cores to perform more than one task at the same time. Parallel processing is a broader term that can be applied in both supercomputing and in traditional multi-core processors, where tasks are carried out simultaneously by dividing them into smaller sub-tasks. This is different from grid computing in which discrete computers that may be spread across diverse physical locations work on different parts or chunks of a larger computing task.
A key difference between grid computing, multiprocessing, and parallel processing is that grid computing relies on a community of computers acting together, whereas multiprocessing involves the simultaneous execution of multiple processes on the same computer, and parallel processing refers to the simultaneous execution of multiple tasks or instructions in parallel by breaking them down into smaller subtasks that can be executed simultaneously.