The PSS cards and other ECHO based cards provide an onboard DSP with 
downloadable programs and also has an AD1848 "Microsoft Sound System" 
device. The PSS driver enables MSS and MPU401 modes of the card. SB 
is not enabled since it doesn't work concurrently with MSS. 

If you build this driver as a module then the driver takes the folowing
parameters

pss_io. 	The I/O base the PSS card is configured at (normally 0x220
		or 0x240)

mss_io		The base address of the Microsoft Sound System interface.
		This is normally 0x530, but may be 0x604 or other addresses.

mss_irq		The interrupt assigned to the Microsoft Sound System
		emulation. IRQ's 3,5,7,9,10,11 and 12 are available. If you
		get IRQ errors be sure to check the interrupt is set to 
		"ISA/Legacy" in the BIOS on modern machines.

mss_dma		The DMA channel used by the Microsoft Sound System.
		This can be 0, 1, or 3. DMA 0 is not available on older 
		machines and will cause a crash on them.

mpu_io		The MPU emulation base address. This sets the base of the
		synthesizer. It is typically 0x330 but can be altered.

mpu_irq		The interrupt to use for the synthesizer. It must differ
		from the IRQ used by the Microsoft Sound System port.


The mpu_io/mpu_irq fields are optional. If they are not specified the 
synthesizer parts are not configured.

When the module is loaded it looks for a file called 
/etc/sound/pss_synth. This is the firmware file from the DOS install disks.
This fil holds a general MIDI emulation. The file expected is called
genmidi.ld on newer DOS driver install disks and synth.ld on older ones.

You can also load alternative DSP algorithms into the card if you wish. One
alternative driver can be found at http://www.mpg123.de/