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Old 13 August 2013, 21:07   #61
Kin Hell
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Join Date: Mar 2009
Location: Cornwall, UK
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Originally Posted by Schoenfeld View Post
There is no DMA on my cards, and neither is there any DMA in the usual way on *any* PCI implementation of the Amiga. What they do is a DMA into PCI gfx card memory (which works great), and then polled-IO to transfer the data from GFX mem into Amiga memory. In essence, the DMA part on the PCI boards is a detour, because most PCI chipsets don't allow direct PIO.

X-Surf (both the 10MBit and 100MBit versions) are pure PIO designs, so in comparison to PCI cards, you skip one step in data transfer, which makes things faster. Remember the prime directive of optimization: The fastest operation is one that you don't execute. Network data doesn't belong in GFX memory.

There is only very few real DMA cards for the Amiga: GVP SCSI controllers, Fastlane (=4091) and Deneb.

I'm aiming at the "Subway" ballpark with the USB module price. You get two High-speed USB ports and a Poseidon license.

WOW! I wasn't aware there were so few DMA compliant cards for the Amiga & yes, Elbox PCI solutions do work quite well despite their DMA fudge/patch, which is where I kinda was with thinking most ZORRO cards were DMA compliant. Digressing, I guess the DMA compliant G-REX4000 ZORRO board blows the Elbox solution because of it's 64Bit memory addressing straight onto the CPU card rather than through the ZORRO III mobo wait-states.
However, with your pricing for the USB module, the Subway gives you 4 ports & an included Poseidon License so shouldn't your price reflect this having only 2 ports & Poseidon now being free? <--- Maybe I read wrong about Poseidon now being free.

Originally Posted by fitzsteve View Post
@Jens, internal USB header would be great if possible on the UBS card for using internal Disk readers, etc
Again Jens, fitz does have a valid point here, especially based on your 2 port only pricing suggestion. - An internal one would offer a far better solution to house some USB device or other within the Amiga case & across many several Big Box Amiga's

Originally Posted by hooverphonique View Post
so this polled-IO is some form of short DMA transfer (64bits?) of data from gfx memory to the pci busboard and then to the cpu via the zorro bus?
ZORRO III is only 32Bit, an upgrade from ZORROII which was 16Bit. Afaik, the only 64Bit operations in an Amiga is via either the CSMKIII or the CSPPC card, where the memory is in essence addressed via two 32Bit channels @ the same time, much like Dual Channel ram is in modern day PeeCees.
Some Graphics cards may also have 64Bit addressing via their RAM but please, please don't shoot me down on this. I am merely thinking this way with the way VRAM works & that is a can of worms I don't even want to try & understand. VRAM blows SDRAM....
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