In the subsection "Device Drivers", the following paragraph metioned the device "Ensoniq IS1370" as an example:

So the es1370.ko sound card device driver might connect the \verb|/dev/sound| device file to the Ensoniq IS1370 sound card.
A userspace program like mp3blaster can use \verb|/dev/sound| without ever knowing what kind of sound card is installed.

but I can't found this device, also the example module name was "es1370.ko". I think it’s referring to the Ensoniq ES1370?