The newer 1522B and 1520B controller has the SCSISelect BIOS and an option to set the DMA channel, yet the transfer rate is fixed on PIO mode. On this older 1522 card, if you set the DT jumper, the text on the screen at boot claims the transfer mode is DMA. Perhaps this is a feature Adaptec removed from the newer 1522B units?
At any rate, the older 1522 card hangs on trying to query the SCSI HDD. I checked all the jumpers. I'm not sure why this is as the same setup works fine on the newer 1520B card I have. Perhaps the issue is related to using the terminator jumpers on the HDD rather than a terminated cable?
I also have a 1540CP card with true DMA bus mastering. This card doesn't work on some 386 boards in combination with the DLC/SXL series of CPUs.
Ideally, I would like to benchmark the 1522 in "2nd-party DMA" and PIO, and compare the results to the newer 1520B and the 1540CP. Anyone run through the various DOS HDD benchmarks to see which are the most sensitive in benchmarks? It is likely that these 3 controllers will be on par, so a very sensitive benchmark would be ideal.
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