Card may not be detected if there is a PCI card using IRQ5. The solution is to edit /etc/rc.d/rcmodules so that the driver is loaded as a kernel module with appropriate settings.
e.g.
.
.
### Sound support ###
# Sound Blaster Pro/16 support:
/sbin/modprobe sb io=0x220 irq=7 dma=3 dma16=5 mpu_io=0x330

It is still working on Debian 3.0r2, Mandrake 8.2, Mandrake 9.0, Mandrake 9.1

The card worked fine for Mandrake 9.1. However FC2 has dropped support for ISA sound cards. :(

Detected and sounded great during FC2 unstall. However, during first bootup and all subsequent boots, a loud hiss comes over the speakers and persists as long as the system is booted. This makes the card unusable in my system. Fortunately, that's OK in this case, as this is going to be my server and won't be doing any games. ;)

works perfect for me

Doesn't work well with ALSA (slow, and quite troublesome). Use OSS instead. Just do "modprobe sb" in case it doesn't get auto-detected (it should if your distro is not using ALSA by default). Hardware MIDI (FM synth) does not get auto-detected, do "modprobe opl3 io=0x388" as root (or with sudo/suid) on a terminal --after the sb module is loaded!!-- and hardware MIDI works. The default OSS volumes for it are too loud (unlike modern cards, the SB16 has a built-in audio amplifier), causing a hiss in the speaker after boot and all the time after - use an utility like aumix to set the volumes to a better level. Other than these, works flawlessly.

I have a special version of this card, which is called a Vibra16X. Linux displays this information in dmesg. The Vibra16X only does half-duplex. In SW7.1, I use:

This is after I use isapnp to initialize the card. On Mandrake 9, there is no need to do this, as the isa-pnp Linux module automatically detects the card and ALSA needs no settings to use the card correctly. On 2.2.x, use the output of isapnp to determine which io, irq, and dma settings to use. Do not specify a value for dma16 if you want your Vibra16X card to work correctly!