Strictly speaking, PC soundcards are very dumb today.
In the mid-late 90s, they reached their pinnacle.
PCM output does essentially mean that they do have an DAC, a D/A Converter (Digital-Analog Converter).
That so-called "digital audio" or "digital speech" of the 80s/90s was referring
to the same and shouldn't be confused with real digital audio, such as SPDIF or HDMI audio.
What late PCM soundcards still supported was sample-rate conversion.
Ie, they could convert an audio stream to their native sampling rate (say 48KHz).
By contrast, older cards like SB16 or WSS could still natively run at different sampling rates (8000, 11025, 22050, 44100, 48000 Hz)..
Speaking under correction, though.
Other platforms had more intelligent soundcards.
The Amiga for example, had 4 independent mono channels that could pan to left/center/right and run at different sampling rates.
That's why authentic playback of 4 channel MODs is so tricky.
All channels must be mixed together to same sampling rate, so that dumb PC soundcards can handle them (have merely zwo channels, which must use same sampling rate, even!).
The up conversion will cause loss a bit of information, though.
90s cards like GUS or AWE were at least capable of mixing in hardware.
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