How did ARPANET differ from earlier time-sharing computer systems?

ARPANET differed from earlier time-sharing systems in two fundamental ways:

• Host-to-Host Connectivity: While time-sharing systems focused on allowing multiple users to access a single central computer via remote terminals, ARPANET was designed to connect a network of independent time-sharing computers to one another. This enabled the sharing of computational resources across different research sites rather than just sharing the capacity of one machine.12
• Packet Switching: Unlike traditional networks that relied on dedicated, hardwired circuits—similar to the telephone system—ARPANET utilized packet switching. This technology breaks data into smaller, independent packets that travel along various routes to their destination, where they are reassembled. This decentralized the intelligence of the network, ensuring it could remain operational even if parts of the system were destroyed, a feature that was highly attractive for military and academic resilience.12

By moving beyond the limitations of single-system time-sharing, ARPANET established the foundation for modern, general-purpose computer networking.12