Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Dragster on September 02, 2003, 10:59:14 PM
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Hi folks!
As you can see in the topic, I'd like to know if the elbox FAST ATA 4000 controller (the Zorro III card) does DMA on an A4000 as I'm thinking of recommending an IDE CDRW but I don't know if it will behave like in the 1200 powerflyer (speedy, but HIGH cpu usage).
Regards,
Dragster
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Unfortunatelly, no. I have The latest Elbox Fast ATA 4000 controller in my A4000 setup (the MK2), and it is still not DMA. However, it's a very good product. Gives you an opportunity of using widely available and up to date ATA devices. It is probably on par speed wise with all the most popular SCSI controllers, if you do not mind CPU usage. It also autoboots. I've made a decision of using it over the SCSI 3 controller in my CSPPC, in order to be able to quickly recover to a new device in case lets say a hard drive dies or so. So in a nutshell, in my opinion, although it's not DMA it is very useful as it allows usage of easily obtainable fast and cheap ATA devices.
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Adding DMA support to card would have increased the costs but the main problem would have been old buster versions...and incompatibilities with other cards due to the use of Z3 DMA. I can't remember many Zorro3 DMA cards. I only remember the old cbm 4091 and the FastlaneZ3, both seem to cause problems. It seems it's difficult to implement z3 dma correctly.
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IMO what would be the point in buying the controller.
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In your opinion? I have no idea. In my opinion, some people still enjoy working with Amiga hardware. :-P
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@mikeymike
being able to burn CDs fast with cheap cd writers is a good point ;-)
Or just to get faster access to your hd...
depending on the number of drives you want to use an ide<->scsi adaptor would be a good idea... it wouldn't slow down your system and still would allow you to buy cheap drives...
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@crumb
I have an DKB 4091 in my 4000 since years and never had problems !
Buster Rev. 11 is needed ofcourse :-D
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@duesi:
Well, I didn't mean that using that cards always gives problems, but if one of these cards don't like the other you'll run into problems... A friend of mine (Hi Reg0 ;-) )has a Picasso4, a Faslane and some other cards and he has problems... And these problems would be even bigger if he used to dma zorro3 cards (an hypotethic ide dma and a scsi dma controller for example...)
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If you want to use modern IDE DMA modes on a classic Amiga - you can't. There's never been an addon that can do it and never will be. The AmigaONE is the only real shot on an "Amiga branded" machine.
pio modes really suck - for classic Amiga systems I'd strongly recommend SCSI, especially BPPC/CPPC SCSI.
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Thanks everybody
Well, the idea was to use cheap IDE CDR(W) drives without having the machine freeze while burning. I guess SCSI is the only real option to use DMA but at a much higher price :-(
Cheers
Dragster
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@ Crumb
"fast" access without DMA? I suppose that depends on your definition of fast. Any time I've had to use IDE devices without DMA support I've likened the experience to nails being scraped down a blackboard :-)
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@mikeymike
my definition of "fast" is being able to burn cds at the maximum cd writer speed instead of 4x
PIO 0 (that's the internal 1200 port) sucks even more than PIO 4. If you don't believe me go to a peecee and force all your drives to run in PIO-0.
Now force all your drives to PIO-4. Is it a big improvement or not?
With a powerflyer you should get around 5MB/s, just like many scsi drives with A1200 controllers...
As I have said that investment depends on the number of drives you plan to use. If you only need a big and fast hard drive, buy an IDE 120GB hard drive for 100€, plug in a scsi<-->ide adaptor and you will get a smooth and fast system. With a cyberstormMK3 or PPC it will probably be the best option (and you will be able to use it with your peggy/AmigaOne if your machine dies).
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I have asked Elbox a couple of months ago if it was possible to create a DMA controller for A1200 and/or A3000/A4000.
They ensured me that it is impossible because of a couple of things in the Amiga design otherwise they would have done it allready.
So basiclly; this is never going to happen. Not because of the cost but because of some design problems which can not be overcome.
It would have helpen or slow processors a lot!
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Oh, and I also asked about a driver for a PCI DMA IDE controller card for the Mediator and that is also not going to happen because of the same reasons in the Amiga design.
A shame really but there is allways AmigaOne with OS 4 when it's ready.
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@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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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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@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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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.
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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.