In the old good days until the middle 1990’s, the sound cards equipped on the PC were all ISA cards. Their typical feature was SoundBlaster16 compatible, that is, 16 bit stereo PCM (pulse code modulation) playback and capture1 . Almost all DOS and Windows games at that time supported the SB16-compatible cards. It had an MPU401 (a serial MIDI) interface shared with a joystick port. It satisfied the demands of both hobby gamers and musicians. The full-duplex capability was not a must.