What are the main functions of ARPANET?

The main functions of ARPANET included facilitating communication between different computer systems, primarily through protocols that allowed for remote access and sharing of resources. Telnet provided users the ability to log into another computer over a network, effectively enabling remote control of systems. File transfer was another fundamental function, enabling the transfer of files between different machines using protocols designed for efficient data exchange. Email emerged as a significant application on ARPANET, allowing users to send and receive messages over the network, which became a primary mode of communication in the early days of internet development.

The combination of Telnet, file transfer, and email captures the core functionalities that were pivotal in the development of network communication. This selection of functions highlights ARPANET's innovative role in creating a foundational framework for future networking technologies.