Back in the day, there was just one file:
It contained a name-to-address mapping for every entity within ARPANET.
/etc/hosts used to be compiled from
It didn't scale for a number of reasons:
- As soon as administrators pulled the latest version of HOSTS.TXT, it would already be out of date
- There was no way to enforce constraints eg; no duplicates on hostnames
- It took a lot of resources to serve it up to every administrator