"No. DMA access to the A4000 motherboard is too slow for PCI cards."
Excuse me but Zorro3 scsi cards use DMA without problems the bandwitch is more than enough to develope scsi drivers or ethernet100 drivers that write directly to the fast ram.
Every data you want to take from the mediator and put in the Fast Ram as to pass trough the Zorro3 bus. With a cpu you have to move everything by yourself and depending on the load of the cpu you may not get 100% of the bandwitch, but with DMA you will get more speed than using the CPU because you can write in fast ram/Zorro3 memory area at the maximum speed your memory allows.
BTW can you prove that using the cpu to move data from a ZorroIII memory area to fastram is faster using the cpu than using DMA? If you plug some ram in a Zorro3 ram card you should get nearly the maximum speed of Zorro3, and with a buffers from a harddisk for example created in that memory you wouldn't be able to get more speed writting and reading using the cpu... the maximum speed you can read/write to the PCI gfx ram depends a lot on the mediator. If it had a better design that allowed you to read/write at 16MB/s, then the current design would be somewhat strange but it would be OK. The problem is that the speed is limited by the mediator to ~9MB/s (remember that I'm talking about A3000/4000 version, and they work in a slightly different way than A1200 versions...)
In conclusion:
how can you say that the Mediator4k is well implemented when you can write to a CV64 (not 3D) at 16MB/s and a Mediator4k in the same machine with a Voodoo5 only gives you ~9MB/s?
"CPU sends data from the graphic card memory to fast ram as fast as the turbo/processor card allows. [...] This speed has nothing to do with Mediator. Mediator is prepared for much higher
speeds, up to 132MB/s."
Sorry, that speed is only achieved between PCI slots, and we are talking about the A4000 version, so the design of the mediator as a lot to do with speed... It works as a ZorroIII card and for your information not all ZorroIII cards work as well, you have excellent implementations like CV64 (not 3D) and crappy ones like CV3D. You can use DMA like in a FastLane Z3 or you can use the CPU like in a PoweflyerZ4. There are different ways of making a ZorroIII card and Mediator3000/4000 is far from being optimal...
"What is a problem? It is obvious that if you would like to use DMA to the motherboard you need to update the buster to rev.9 as a minimum."
The problem is that it gets exactly the same speed because every data movement from the mediator to the fastram is done by the cpu, just because it doesn't do DMA between the Mediator and the FastRam... That's the reason the Buster doesn't matter
"Quote:
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Zorro3 should give you a bandwitch of 16MB/s with a gfx card (like a CV64 not 3D), not around 10MB (on the 4k version) like now with a Mediator4k or a Picasso4...
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This bandwidth depends on the processor card, not on Mediator."
In the 1200 version yes, in the 4000 version NO. In the 4000 version Mediator is no more than a Z3 card and mediator's design affects a lot to the performance of PCI cards.
"I have never heard that anybody has more than two stable operating DMA cards with a Grex.
So, drivers for them are useless "
Maybe you are talking about the 1200 version, which only has 2 DMA slots. In the G-Rex 4000 all slots have DMA.
"USB for Grex is vapourware."
at the moment yes.
"OpenPCI is nothing interesting for Mediator users. Mediator has MANY more drivers than other PCI solutions. See here "
Voodoo3/4/5, Permedia2, SiS, BT878/848, SB128, Terratec,Ethernet10/Ethernet100,etc... The only driver Mediator has and G-Rex has not is USB.
Anyway you can't register Poseidon if you buy a Spider now, so it's a card without drivers unless you are a pirate.
So I guess I can say that the Spider is "vapourware" because you have not (legal) way to make it work (or you won't have in 10 days if Elbox doesn't come to an agreement with Chris Hodges).
LOL :-D
