As I understand it, the oss-compat package is supposed to enable ALSA's OSS compatibility layer to create /dev/dsp files for your sound devices for compatibility with older applications. It's description states:
The purpose of this package is for applications that only support OSS
to depend on it, hence preventing common "/dev/dsp not found" errors
that would confuse unexperienced users.
Yet after installing it, no /dev/dsp devices have been added to the system and older applications still have the same problems. Other OSS emulation instructions also did not work.
I though it might have trouble as I have two sound devices (a sound card and tv/fm tuner), but physically removing one device and restarting made no difference.
I have also tried the aoss and padsp OSS wrapper applications but without success (works for applications not seeing /dev/mixer, but not those that require /dev/dsp).