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AHA-1542CF + PAS16 = problem

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Xacalite

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I've got a 386DX/40, which was working fine with AHA-1520B (non-bus-master, DMA disabled) and Pro Audio Spectrum 16.
But I've replaced the SCSI host adapter with AHA-1542CF (bus-master, needs DMA).
Seemed to work great, disk throughput increased by 40%.
But then I tried to play some music - WAV files using PLAYFILE, and MOD files using Inertia Player - and it turned out that simultaneous sound playing and disk activity is impossible, the sound just stops.

It can't be typical resource conflict:
AHA-1542CF is set to 130h, IRQ 11, DMA 6
PAS16 is set to 388h, IRQ 7, DMA 5 (and 220h/5/1 for SB emulation, though only using native software here)

Changing AHA-1542CF DMA channel to 0 helps a little - the sound doesn't stop at once, but distortions can still be heard.
Also, disk throughput is a little slower - obviously because DMA 0 is 8-bit.

Any idea what's going on?
Are there any known issues with AHA-1542CF?
I thought it was the best ISA SCSI host adapter ever, but now I'm thinking about going back to AHA-1520B...
 
DMA is a pretty limited resource on the ISA bus. I suspect that it may be the root of your problem. Have you tried a SCSI controller that uses programmed I/O?
 
Chuck(G) said:
DMA is a pretty limited resource on the ISA bus. I suspect that it may be the root of your problem. Have you tried a SCSI controller that uses programmed I/O?
Click to expand...

Yes, I was running AHA-1520B in PIO mode - worked fine, with HDD throughput of 882 KB/s.
AFAIR I also experimented with DMA mode, but there was no performance increase.
AHA-1542CF achieves 1200+ KB/s, so I don't want to go back to AHA-1520B if there's a better solution.

Trixter said:
The solution in that post is "In the manual is a "work-around" for DOS where you can adjust the Bus-on/off-time of the AHA. Then it work fine (under Dos !)."
Click to expand...

So I tried this, the Adaptec EZ-SCSI manual recommends the following solution to problems with floppy tape/drive backup software:
ASPI4DOS.SYS /f12 /n4
Sound playing is better, but still not perfect, and the HDD transfer rate is down to 663 KB/s.
The longest bus-off and the shortest bus-on combination (/f64 /n2) slows down the HDD to 85 KB/s, where playing CD-quality WAVs is certainly impossible.

This sucks.
I think I'm going to try replacing the PAS16 with some boring SB16, as soon as I get one...
 
Well, I will also be looking for yet another SCSI card.
BTW: there's also a DMA-using NIC (channel 7) in that 386 - works fine together with AHA-1542CF.
Also, no problem playing sound in SB mode - but it's only 22kHz/8-bit/mono...
 
The problem is that legacy DMA can't do much better than 1 MBps in real-world settings--and often much worse than that. Busmastering DMA can do better, but at the expense of legacy DMA. You can't really win this one with ISA DMA.
 
Xacalite said:
I've got a 386DX/40, which was working fine with AHA-1520B (non-bus-master, DMA disabled) and Pro Audio Spectrum 16.
But I've replaced the SCSI host adapter with AHA-1542CF (bus-master, needs DMA).
Seemed to work great, disk throughput increased by 40%.
But then I tried to play some music - WAV files using PLAYFILE, and MOD files using Inertia Player - and it turned out that simultaneous sound playing and disk activity is impossible, the sound just stops.

It can't be typical resource conflict:
AHA-1542CF is set to 130h, IRQ 11, DMA 6
PAS16 is set to 388h, IRQ 7, DMA 5 (and 220h/5/1 for SB emulation, though only using native software here)

Changing AHA-1542CF DMA channel to 0 helps a little - the sound doesn't stop at once, but distortions can still be heard.
Also, disk throughput is a little slower - obviously because DMA 0 is 8-bit.

Any idea what's going on?
Are there any known issues with AHA-1542CF?
I thought it was the best ISA SCSI host adapter ever, but now I'm thinking about going back to AHA-1520B...
Click to expand...
I had my 1542CF at port 140, IRQ 11 and set it as legacy ISA in the board Bios. Don't think I ever mucked about with DMA in those days.

Kev
 
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