FOSSIL driver

FOSSIL stands for Fido/Opus/SEAdog Standard Interface Layer and was born in the FidoNet world. The driver loaded as a TSR and offered a uniform set of calls through INT 14h; programs like Synchronet, mailers and door games talked to it instead of poking the UART registers directly.

The payoff was that a single driver — X00 and BNU were the common ones — handled buffering, flow control and odd serial hardware, so every BBS package was spared rewriting the same code. An early example of a driver layer abstracting the port away, exactly the job operating systems later took over.