Amiga.org
Amiga computer related discussion => Amiga Marketplace => Topic started by: redrumloa on March 06, 2004, 10:02:24 PM
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Make an offer for the bare motherboard with 128Meg of Resistered SDRAM, or if you wish I can quote a built complete system. If you wish a quote for a complete built system, state what specs you require.
This being a pre-April means DMA is completely disabled. This is good for maybe a developer board or to wet your feet in the world of Pegasos.
-Edit- And before you ask, no this is not from my Peggy system.
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This being a pre-April means DMA is completely disabled.
Erm... if you run MorphOS on it you always have DMA _enabled_. It is still good for development purposes but proper precautions (i.e. backups) are recommended :-)
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(http://www.odin1.dds.nl/junk/redrum.jpg)
Slight typing error there redrum :-)
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odin wrote:
Slight typing error there redrum :-)
Umm.. yeah.. I'll speak with my marketing department! Thanks for the tip :-D
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I spoke with marketing, they fixed it. Thanks again:-D
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:-D
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as i'm not a hardware nerd, but I have a Pre-April peg. tell me what "DMA is completely disabled" means.
I use the system only to test software since the USB port isn't working at the moment (I may need to make some connections, have to investigate that).
Since the USB ports are not working I can't copy any files FROM the peg, but I can burn files on CD's to get stuff onTO the peg. it's all one way atm.
anyway, that's besides my point. I just want to know what this DMA means to me, if anything.
thanks.
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Well, DMA is an abbrevation for 'Direct Memory Access'. Meaning that the chip concerned can read/write directly to memory. I.e. it doesn't need to use the main CPU to read/write, thus taking load of the CPU leaving that free to do more important stuff :-). With DMA data moves directly between chip<->RAM, without DMA it moves in the following fashion: chip<->CPU<->RAM.
In the case of the peg (and A1) this story concerns DMA of the IDE controller, supposedly the controller has hardware bugs.
Not 100% of that...(Bill Buck seems to be though and Alan Redhouse not (or something);-)).
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hmm, ok. so that would make things slightly "slower". well, no biggy as it all seems mighty fast to me!
thanks.
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@odin
Semi right, the problem concerns DMA access period, not just of the IDE bus. If you run SCSI, Firewire, ethernet, etc, all of it can use DMA, and in these motherboards, DMA does not work. This makes all of it slower than otherwise.
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@cecilia
With a high MHz CPU it probably doesn't matter too much, I guess. However I sometimes still bang my head against the wall for not getting a BlizzardPPC with SCSI onboard, I'm still stuck with the crappy onboard IDE controller (and a lousy 040 for that matter).
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@downix
Ah okay.....
/me waits for other people to contradict ;-).
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Ah okay.....
/me waits for other people to contradict .
Rogue has been contradicting Downix for a long time on this matter. Recent statements by Rogue have declared DMA to be known working with some functions of the AmigaOne board under OS4 (like ethernet, as Downix noted is able to utilize DMA). IDE DMA has been said by Rogue to be working, but not with the driver system of OS4 yet, not because it can't, but because they haven't yet implemented it in the driver.
This was just a day or two back at AmigaWorld.net
Paul
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It's now on eBay (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2792462803)!
:-)
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How much ?
I'll offer TEN BOB..... curiosity value
:-o :-o
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hi Cecilia
Since the USB ports are not working I can't copy any files FROM the peg, but I can burn files on CD's to get stuff onTO the peg. it's all one way atm.
have you tryed to contact DCE? They may fix the problem in a reasonable time :roll:
Ciao ;-)
PS- ops sorry, i wanted to say. . . . to contact BPlan that then will . . . .
/troll mode END
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by downix on 2004/3/7 2:12:52
@odin
Semi right, the problem concerns DMA access period, not just of the IDE bus. If you run SCSI, Firewire, ethernet, etc, all of it can use DMA, and in these motherboards, DMA does not work. This makes all of it slower than otherwise.
ok downix but whats about the "audio corruption" and "IDE Lockup" of those hardware revision?
It isn't a mere "speed" problem!
Ciao :-)
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It's sold! :-)
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@Framiga
With DMA disabled, neither occurs, hence slowness becomes the problem.
If you choose to use DMA in a DMA-unsafe situation, corruption will occur, weither this means sound corruption, memory thrashing, etc. Then the situation becomes one of the consumer running the machine in a non-prescribed manner.
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@Paul
Rogue can contradict me until the cows come home.
Has he ever designed a motherboard using the Articia-S? No.
Has he ever even taken an EE course? No.
Has he ever even run a circuit diagnosis? No.
Fact is, he is not in any position to discuss a hardware problem. He is a talented software engineer. When all you have is a hammer, all of your problems look like nails. That is the case here.