KNOPPIX DMA

[brunomfpaula]

Hello all, I'm using knoppix live CD and i would like to know if activating "knoppix dma" during the boot really incrises the speed or if it makes any harm for my PC.

I'll wait for an answer, thaks anyway.

[Harry Kuhman]

Hello all, I'm using knoppix live CD and i would like to know if activating "knoppix dma" during the boot really incrises the speed or if it makes any harm for my PC.

I'll wait for an answer, thaks anyway.

AFAIK, DMA is now the default. Some older systems need the nodma cheat code, but the DMA cheat code should have no effect.

[Cuddles]

Hello all, I'm using knoppix live CD and i would like to know if activating "knoppix dma" during the boot really incrises the speed or if it makes any harm for my PC.

I'll wait for an answer, thaks anyway.

I know I posted this FAQ in a previous posting ( sometime ), but, could not locate the thread I had put it into, so, here goes again...

From the "Microsoft Support" web site:

Here is the LINK

This is the "Definitions of Common Integrated Drive Electronics (IDE) Terms"

And here is the "snippet" of the DMA definition:

Direct Memory Access (DMA):
A method of ATA transfer that makes use of DMA controller to bypass the CPU. Also supports bursting and bus-mastering to achieve higher transfer rates. There are 3 overall standards that are further divided: Single Word (mode 0 - mode 2) supporting speeds from 1.04 Mbps to 4.14 Mbps, Multiple Word (mode 0 - mode 2) supporting speeds from 4.17 Mbps to 16.7 Mbps, and Synchronous DMA (mode 0 - mode 4) supporting speeds from 16.6 Mbps to 66.6 Mbps.

and to include the ATA "snippet" definition:

AT Attachment (ATA):
The specification or standard that an IDE device should conform to for connecting to a computer.

just to include this, the definition of IDE:

Integrated Drive Electronics:
A generic term term that can be applied to any drive with an integrated controller.

I can easily say, I have a hard drive ( Samsung ), that refuses to let me use DMA on it, I usually have to "force" DMA off on this drive, or I get floods of errors in my system log when the drive is either mounted or touched. Having DMA dissabled on one drive, while the other drive has it enabled, has not proven to be a problem; I have had no errors, and no "noticable" speed / transfer rate issues. From the above "quotes", I gather that DMA is only for having "faster" speeds of drives, and if you dont notice the usage, or lack of, using DMA, then its only "water under the bridge" kind of thing...

Upon, running around to locate the above links and data, I did come about "programming" at the system level for Windows Server, and the "census" of Microsoft is, that some devices, of these being of the "older" age, may not allow usage of DMA on them, and, being the "good" OS that Microsoft is, they will "depreciate" any devices that fail with DMA of five or more errors, down to PIO, and dissable the use of DMA on these devices.

So, you may want to try DMA on your devices, and if you get errors, dissable DMA... If all goes well, then leave DMA enabled... This can be for any device, and any age... Since you can buy a new device, but the device may be using a controller that may be older.

Hope this helps, a little
Ms. Cuddles

[brunomfpaula]

Thanks to all, i have no more doubts about it.