I think Michael made a slight mistake w/ regard to Rev.9 Buster and an A4091. The 4091 won't work at all w/o a Rev.11 Buster in the A3000 or A4000 desktops. When said card is installed with a Rev.11 in these desktop versions; you can't install a Deneb and operate it in DMA mode. You'd have to use the PIO mode as the 4091 operates as the sole Zorro III busmaster. I think he meant to say the Rev.11 only allows one DMA Zorro III Busmaster, either an A4091, Fastlane or Deneb. If you have a Rev.9 Buster, you can operate a Fastlane and a Deneb in DMA mode because the Rev.9 chip allows more than one Busmaster and both the Fastlane and the Deneb have workarounds to allow for Rev.9 and the conflict problem (though your mileage may vary).
The A4000T is different because it implements the A4091 on the m/b and there is an additional busmastering conflict as a result, which prevents use of the Deneb whatsoever in DMA mode (and maybe even PIO mode, though I'm not certain). Since all A4000Ts also have Rev.11, even if you don't use the on-board SCSI controller, they again allow only one ZIII busmaster (e.g. a Deneb, Fastlane, etc.). So again I think what he's saying is if you have more than one DMA ZIII card in an A4000T w/Rev.11 (really this is limited to either a Fastlane or Deneb) you'd have to run the Deneb in PIO mode and let the Fastlane run in DMA mode. There shouldn't be a problem with other ZIII cards like the PicassoIV, Cybervision64, Prometheus, etc. as these are not true ZIII busmastering cards (though that may change with the Prometheus as I've read E3B is working on a DMA fix for that card).
.....My apologies to Michael if I got this wrong.
