3.12. Napster was a famous music exchange system that additionally offered many add-on services. It was sentenced to go out of business due to copyright infringement. The system worked as follows. The Napster server held a database of all music files offered by the participating users. Users had to login to the Napster server, and send the list of files they offered. Each user could then send search requests to the Napster server, in order to receive a list of the users that offered files that matched the query.
The requester could then choose a user from that list, establish a direct connection with him, and request a download of the file.

a. Categorize the relationship between the Napster server and the users of the system as either client/server or peer-to-peer.

b. Categorize the relationship between the users of the system as either client/server or peer-to-peer.

c. Categorize the database of music files as centralized, decentralized, or distributed, and analyze the economic implications on the system.

d. Categorize the database containing the list available music files as either centralized or distributed, and analyze its technical implications.

e. Analyze the relationship between the Napster system architecture and the vulnerability of Napster against legal actions.