Which is the better scsi card for the A4000?

[AmigaPixel]

They are both pretty crap.

Both are Zorro II without DMA and so offer no bandwidth or CPU load advantages over using the A4000's IDE.

Unless you've got a SCSI device you want to use... I'd leave them "lying around" and save electricity.

I partly disagree, I owned a IVS Trumpcard for my A2000 in 1993, and yes! it was flaky. Although some improvement came after I upgraded the rom.

I switched to The Expansion Systems Data Flyer Plus-SCSI/IDE combo board. It has ran flawlessly for 16 years until recently. However that is an issue with the PSU failing. Correct me if I am wrong but isn't even SCSI I still have a faster throughput than the early IDE channels found on classic Amigas? even with out the DMA, I could be all wet on this, it has been a long time in the classic Amiga hardware era for me. Maybe the later EIDE AtA 66, and ATA100 were better performers

[AmigaPixel]

I don't think so. Both are PIO and both are 16-bit.

I see your point, I was thinking SCSI I was 32bit. I just remember SCSI(at least SCSI II and  III) was the preferred hard drive/interface for video editing and animation for a long time. I guess unless you have Zorro 3 SCSI II or III board, sticking to the IDE on an A4000 would be a better choice. That is unless you have SCSI devices that you really need to use.

[AmigaPixel]

I am still a little confused at how and when the Amiga made use of PIO versus DMA, specifically with SCSI and IDE configurations. I remember it was always a big deal that the Amiga had DMA channels

[AmigaPixel]

@alexh

OK thanks for clearing that up. Is Gayle the IDE controller in AGA machines?

[AmigaPixel]

Yes I think this is true. A GVP controller with RAM for example has DMA. You must use the memory mask fields in the RDB to constrict the memory the SCSI driver will use.

Obviously this RAM is 16-bit and has a bandwidth limitation when used by a 32-bit CPU.

Some accelerators have their own 32-bit CPU, 32-bit RAM, SCSI controller and DMA controller to overcome these problems. (Cyberstorm for example.)

I had a Phase 5 Blizzard 060 and SCSI II controller in my A1200, I wonder if controller was 32bit with DMA? I don't remember the specs. The SCSI board also supported 72 pin SIMMs like the 060 accelerator.

[AmigaPixel]

The ram was 32bit & supported dma. You wouldn't need to have a simm on the blizzard scsi board, it's just for extra ram expansion. But you would at least need some ram on the accelerator.

Actually I think it was the Blizzard IV SCSI II controller, which according to "The Big Book of Amiga Hardware" was a 32 bit DMA able. At the time I had a 16MB SIMM on the accelerator and 4MB SIMM on the SCSI. That little 060 ran hot, I use to take the trap door off and raise it up about 1/2 inch for better air flow. I then aimed a house fan on the A1200 when I was rendering 3D animations. I sometimes wished I hadn't sold all of it.