DMA / ATA Hard drive help

[Turnip12]

Could some please explain DMA and ATA to me? Is there a difference or are they the same thing? Say I buy a motherboard with a DMA-100 Controller, will ATA-100 Hard drives work with them and is there anything special I have to do? Any info on the subject would be appreciated, thanks.

[Mykex]

ATA-100 is the transfer rate and DMA is Direct memory access you can have an ATA100 controler not a DMA 100. If you have an ATA100 controler you can enable DMA on the HDD device to improve performance. Hope this helps a little.....

[Brangwen]

Turnip:

The previous post is accurate. I have an IBM ATA/100 hard drive cabled to my motherboard. Before enabling DMA, my drive benchmark using Sandra was less than UDMA/33! After enabling DMA (Direct Memory Access), the Sandra benchmark for my hard drive was incredibly high. ATA/100 (I believe - more knowledgeable members will be able to provide you with more information) refers to data transfer rate, and I believe more specifically "data burst" speed or size. Enabling DMA dramatically increases the hard drive performance, but I will leave it for the more knowledgeable members to explain to you exactly how this is accomplished. I believe I knew at onetime, but have forgotten.

If you bought a mobo that supported ATA100, you must use a ATA100 cable. These are usually included with the motherboard. The motherboard may have to be jumpered for ATA100, then again it might be "picked up" or set automatically depending on the board. You will have to go into Device Manager (e.g., Win98se) and enable DMA by checking the DMA box in settings under the HD controller.

Hope this helps!

Brangwen http://www.sysopt.com/forum/wink.gif



[This message has been edited by Brangwen (edited 04-08-2001).]

[Turnip12]

Thanks for the info guys. Just one more qustion to some it up for me then. At a certain website, componentsdirect I think, they list hard drives at either ATA or DMA. Does that mean that the ones they list as ATA can not have DMA enabled and the ones they list as DMA can? Basically ATA is the type of hard drive and DMA is a function that can or can't be enabled on it? Thanks again for the help.

[Fingers]

ATA-100 and U(ltra)DMA-100 are really the same thing. I believe all new IDE hard drives are DMA (Direct Memory Access) capable, whether the manufacturer chooses to label them as ATA-xx or UDMA-xx. Some CD-Roms and CD-R(W)'s are DMA capable; some are not.

[Turnip12]

Thanks for the clarification.