Complex sentence: On the ARPANET, hosts were given names to be used in place of numeric addresses and a HOSTS.TXT file was distributed by the NIC and manually installed on each host on the network to provide a mapping between these names and their corresponding network address.
Split into simpler sentences: On the ARPANET, hosts were given names to be used in place of numeric addresses. A file named HOSTS.TXT was distributed by the NIC and manually installed on each host on the network to provide a mapping between these names and their corresponding network address.