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Author Topic: Is Elbox A4000 ATA controller DMA?  (Read 4015 times)

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Offline Kronos

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Re: Is Elbox A4000 ATA controller DMA?
« Reply #14 from previous page: September 03, 2003, 08:16:09 PM »
@PQuasar
Not really in the Amiga-design, but in the Mediator, which just couldn`t handle
such an amount of data (*), the Mediator isn`t a Z3-DMA card itself and has no ROM
to allow autobooting from such a controller.


Nuff said ;)



*Yes I know Elbox's babble bout benchmarks, but these are allway between a PCI card
and a nonexistan PCI-master(shark). Transferrate PCI to Zorro/Amiga are dead slow in
comparison.
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Offline Crumb

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Re: Is Elbox A4000 ATA controller DMA?
« Reply #15 on: September 04, 2003, 11:37:30 AM »
Mediator has not DMA to the Amiga Motherboard because it would be really tricky (if not impossible) to do with the 1200 version.

With the A4000 version (I'll call it Zorro3 version) the situation is quite different because DMA can be done (You can buy fastlanes in ebay, they aren't vapourware and they do DMA to the motherboard). It wasn't implemented due to cost: Initially you may think in Commercial reasons (afaik Buster7 can't do DMA in Zorro3... with the Mediator3/4000(T) it doesn't matter because until Buster11 you couldn't have bus master cards that worked correctly). But then you think... why didn't they put a jumper to select the buster version?
A DMA card is far more complex in zorro3 than a non DMA one and takes much more engineers time to test it, may require more expensive components... I think that the final reason is cost or lack of engineering experience and knowledge of the Zorro3 bus.

On the other hand, it seems they have done a good job if we forget the lack of DMA...
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Offline Kronos

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Re: Is Elbox A4000 ATA controller DMA?
« Reply #16 on: September 04, 2003, 11:52:41 AM »
@Grumb

Z3-DMA just isn't possible with the programmable chips used on the Mediator.

Using different chips would result in a completly different design ;)
(and would cost a fortune with such few units build)
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Offline Damion

Re: Is Elbox A4000 ATA controller DMA?
« Reply #17 on: September 04, 2003, 12:17:31 PM »
The whole point of having a "big box" amiga
are the nice SCSI options! ;)

In a 1200 I would probably rather have the
"powerflyer" over the internal IDE, since
CPU usage is still around 80-99% with
the stock IDE anyway. But IMO the lack of
DMA transfers is a serious drawback for an
expensive controller.

-edit-
Best bet for non-DMA IDE controller on the 1200
is the "IDE Fix Express". Around 5mb/s
and only about 30 euro. This would be nice
for a compact flash to IDE adapter and
32x flash card (4 mb/s) to install your
boot partition on...quick 4 second boots,
and all other partitions/drives on Blizzard SCSI.
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