Welcome, Guest. Please login or register.

Author Topic: AmigaOne DMA Problem  (Read 11587 times)

Description:

0 Members and 1 Guest are viewing this topic.

Offline captainmoomooTopic starter

  • Jr. Member
  • **
  • Join Date: Sep 2003
  • Posts: 70
    • Show only replies by captainmoomoo
AmigaOne DMA Problem
« on: June 28, 2004, 10:44:28 PM »
Hi - what is the deal with the DMA problem in the AmigaOne hardware? Will this also be an issue for the microA1? If so, what are the implications? Is this a problem for AmigaOS4 as well as Linux?

I've tried searching around on the net for info on this, but havent really found a coherent explanation. Any help on this matter here would be greatly appreciated, as it is a factor in me deciding whether or not to buy an AmigaOne/microA1.

Thanks
 

Offline SamuraiCrow

  • Hero Member
  • *****
  • Join Date: Feb 2002
  • Posts: 2281
  • Country: us
  • Gender: Male
    • Show only replies by SamuraiCrow
Re: AmigaOne DMA Problem
« Reply #1 on: June 29, 2004, 12:04:37 AM »
For a full explanation read here.  But suffice to say that the DMA bug only affects Linux not AmigaOS 4.
 

Offline KennyR

  • Hero Member
  • *****
  • Join Date: Mar 2002
  • Posts: 8081
    • Show only replies by KennyR
    • http://wrongpla.net
Re: AmigaOne DMA Problem
« Reply #2 on: June 29, 2004, 12:32:27 AM »
OS4 has workarounds for the Articia bugs. Whether or not they give full performance is yet to be seen. MicroA1 also has Articia. Linux doesn't have these workarounds, which is why UDMA on A1/Linux doesn't work properly.
 

Offline takemehomegrandma

  • Hero Member
  • *****
  • Join Date: Oct 2002
  • Posts: 2990
    • Show only replies by takemehomegrandma
Re: AmigaOne DMA Problem
« Reply #3 on: June 29, 2004, 01:05:25 AM »
The A1 "hardware issues" derives from the MAI Articia S Northbridge. But there seems to be split opinions whether the "issues" are good or bad.

Some people thinks that it's an unknown/undocumented *feature* of the Northbridge hardware, and that it's the LinuxPPC operating system that is problematic and unstable, and that is the explanation to why the OS crashes and files gets corrupted.

Other people thinks that it's a bug in the Northbridge hardware and has either dropped development of the boards based on this chip and/or developed hardware patches (in plural) for it. The LinuxPPC operating system works fine with these patches, and even better when the Articia northbridge is completely left out of the picture in favour of another one.

Some people has also observed that even the MAI data-sheets about the Articia S no longer mentions DMA support, nor did the Article about MAI products in "IBM PowerPc News" (compare the different chips in the "Miscellaneous" row of the table, two has DMA, one has not (guess which one)). So to some people it seems obvious that not even the manufacturer themselves is prepared to sell the Articia northbridge used in the A1 as DMA capable anymore. You asked: "Hi - what is the deal with the DMA problem in the AmigaOne hardware"? The answer would be: There is none! No DMA that is! :lol:  :-P At least if you should believe the manufacturers themselves ...  

The Articia S has a lot of other issues too; it is very picky when it comes to peripheral hardware (and the way you connect them), such as memory, CD-ROM drives, etc. It also uses a kind of memory that is getting quite old, expensive, rare and hard to get. Only to mention a few things ...
MorphOS is Amiga done right! :)
 

Offline HotRod

  • Sr. Member
  • ****
  • Join Date: Mar 2002
  • Posts: 370
    • Show only replies by HotRod
Re: AmigaOne DMA Problem
« Reply #4 on: June 29, 2004, 01:20:45 AM »
There are no bugs only claims. I've read the specs for the Atricia S since some months back (allmost a year) and I haven't seen DMA mentioned for the Atricia S. It's handled in software, not in hardware.

The AOS 4 driver works. It is 100% reliable.

It is picky about the RAM-chips being used. Except from that I haven't seen any problems and I use regular PC-stuff with different brands. I've tried three different gfx-cards, different soundcards, network-cards and so on and they have all worked.

There are more claims than truth. The only thing that is true is that it's picky about the kind of RAM-chips being used. That is easily solved. Just buy the brand that works.
 

Offline itix

  • Hero Member
  • *****
  • Join Date: Oct 2002
  • Posts: 2380
    • Show only replies by itix
Re: AmigaOne DMA Problem
« Reply #5 on: June 29, 2004, 02:01:29 AM »
Quote
There are no bugs only claims.

How about tv cards?
My Amigas: A500, Mac Mini and PowerBook
 

Offline adolescent

  • Hero Member
  • *****
  • Join Date: Sep 2003
  • Posts: 3056
    • Show only replies by adolescent
Re: AmigaOne DMA Problem
« Reply #6 on: June 29, 2004, 02:03:52 AM »
Quote

HotRod wrote:
The AOS 4 driver works. It is 100% reliable.


But at what speed?  I'd venture to guess that sofware DMA is slow and CPU hungry.  Also, I see a few posts about very slow CD-ROM speeds on OS4.  Is this due to not having DMA?
Time to move on.  Bye Amiga.org.  :(
 

Offline graffias79

  • Sr. Member
  • ****
  • Join Date: Sep 2003
  • Posts: 335
  • Country: us
  • Gender: Male
    • Show only replies by graffias79
Re: AmigaOne DMA Problem
« Reply #7 on: June 29, 2004, 03:40:13 AM »
Quote

adolescent wrote:

But at what speed?  I'd venture to guess that sofware DMA is slow and CPU hungry.  Also, I see a few posts about very slow CD-ROM speeds on OS4.  Is this due to not having DMA?


If the DMA mode used was CPU hungry it would defeat the purpose of Direct Memory Access, wouldn't it?

-Jamie
 

Offline Bodie

  • Hero Member
  • *****
  • Join Date: Dec 2002
  • Posts: 671
    • Show only replies by Bodie
Re: AmigaOne DMA Problem
« Reply #8 on: June 29, 2004, 03:41:40 AM »
Quote

itix wrote:
Quote

There are no bugs only claims.


How about tv cards?


My tv card works fine here.
 

Offline itix

  • Hero Member
  • *****
  • Join Date: Oct 2002
  • Posts: 2380
    • Show only replies by itix
Re: AmigaOne DMA Problem
« Reply #9 on: June 29, 2004, 04:50:25 AM »
Quote
Quote
Quote
There are no bugs only claims.
How about tv cards?
My tv card works fine here.

Bug or not?
My Amigas: A500, Mac Mini and PowerBook
 

Offline Bodie

  • Hero Member
  • *****
  • Join Date: Dec 2002
  • Posts: 671
    • Show only replies by Bodie
Re: AmigaOne DMA Problem
« Reply #10 on: June 29, 2004, 05:04:52 AM »
Quote

itix wrote:



Bug or not?
[/quote]

Don't know, I can't speak for PegI owners ;-) . All I know is that I can view tv (yes, before you ask, with sound) on my A1 under Linux.



 

Offline captainmoomooTopic starter

  • Jr. Member
  • **
  • Join Date: Sep 2003
  • Posts: 70
    • Show only replies by captainmoomoo
Re: AmigaOne DMA Problem
« Reply #11 on: June 29, 2004, 08:30:19 AM »
everything i read seems to make me lean towards a pegasos2 rather than an amigaone.

but then i also read somewhere that MorphOS might be released for the Mac, in which case I might just be better off getting a cheap one of those.

too much choice...

- announcement by mikeymike: off-topic -
 

Offline Miky060

  • Newbie
  • *
  • Join Date: Apr 2002
  • Posts: 17
    • Show only replies by Miky060
Re: AmigaOne DMA Problem
« Reply #12 on: June 29, 2004, 09:21:28 AM »
> everything i read seems to make me lean towards a pegasos2 rather than an amigaone.
> but then i also read somewhere that MorphOS might be released for the Mac..

Naa, IF it will happen, this will happen NOT TOMORROW, neighter the day after tomorrow..
So buy a PegasosII, it's cheap, damn fast and it has MorphOS. Believe me, when you will try MorphOS on Peg you will want one immediately! ;-)

- announcement by mikeymike:  off topic -
------------------------------
PegasosII G4 \\\'Elite\\\' Machine
------------------------------
Ram: 512 MB DDR
Gfx: Radeon 7000 PCI + Voodoo5 5500 AGP
TV board: Terratec TV Value
Audio: Creative Sound Blaster Audigy
Monitor: Lacie ElectronBlue 22\\"  :-D
------------------------------
http://www.pegasos-italia.com
------------------------------
 

Offline mikeymike

  • Hero Member
  • *****
  • Join Date: Nov 2002
  • Posts: 3420
  • Country: 00
    • Show only replies by mikeymike
Re: AmigaOne DMA Problem
« Reply #13 on: June 29, 2004, 09:31:09 AM »
The original poster wasn't asking about the Peg, but about the A1.

Regarding the A1 and DMA, what I would really like to see now is someone who is as unbiased as possible to run lots of practical and synthetic tests on it running OS4 and post the results/their findings.

As a potential customer, I would feel a lot more comfortable about an A1 purchase once I had seen both official and unofficial reports that sound sane and essentially agree with each other.  I'm not implying the opposite (or near opposite) has happened at any point either.
 

Offline Hooligan_DCS

  • Hero Member
  • *****
  • Join Date: Jul 2002
  • Posts: 522
    • Show only replies by Hooligan_DCS
Re: AmigaOne DMA Problem
« Reply #14 on: June 29, 2004, 09:37:53 AM »
The original poster himself "drew" Pegasos into this thread.. sort of... too...