" Hardware Support and Real Mode DOS didn’t really support hardware devices in the way operating systems support hardware today. Programs that needed to directly access hardware — for example, a DOS game that wanted to use your sound card to output sound — had to support that hardware directly. If you were developing a DOS game or a similar application, you’d have to code in support for all the types of sound cards your users might have. Luckily, many sound cards were Sound Blaster compatible. You’d use a SETUP program to configure this setting separately for each program you used. " https://www.howtogeek.com/188980/pcs-before-windows-what-using-ms-dos-was-actually-like/