Practice a Create-Performance-Task-style written response about the Internet, fault tolerance, and parallel computing. Write your response, then reveal the model answer to see exactly what earns each point.
Note: The AP CSP exam is all multiple-choice; extended writing appears in the Create Performance Task. This question gives you practice with that style of written response.
A company runs a popular video-streaming website. Users all over the world request videos, which are sent from the company's servers across the Internet to each user's device.
The video data is broken into many small packets, each labeled with the destination device's IP address. These packets travel independently across the Internet, forwarded by routers along paths toward that address, and may take different routes. When they arrive at the user's device, they are reassembled in the correct order to recreate the video.
Because the Internet has redundancy — many connections and multiple possible paths between the server and the user — the packets can simply be routed around the failed router along a different path, so the video still arrives. This ability to keep working even when a component fails is called fault tolerance.
Splitting the conversion job across many separate networked computers is distributed computing (it would be parallel computing if it used multiple processors within a single machine). A key benefit is speedup: dividing the work lets many videos be converted at the same time, finishing far faster than one computer working sequentially. A limitation is that the speedup is not unlimited — coordinating the computers adds overhead, and any part of the task that must be done in order cannot be sped up by adding more machines.