what is DMA and why should I turn it OFF

[barth]

As a dedicated mac user who recently bought a wintel just for svcd burning, I was wondering
I've noticed a dramatic system improvement with DMA turned while capturing video.
what is dma and why do I have the choice to turn it off. Are there any disadvantages if left on any time?

[MOVIEGEEK]

I'm no Mac expert but DMA stands for Direct Memory Access.It allows
the hard-drive & cd-rom to run without accessing the cpu allowing
faster throughput(usually).If your bios was made before 6/2000 then
I would leave DMA off.

[vitualis]

There is no reason to turn off DMA unless you are having problems with it on (and there shouldn't be).

You should turn/leave DMA on for all systems that support it (which definitely includes PCs before 6/2000).

Regards.

[khelms]

I'm no Mac expert but DMA stands for Direct Memory Access.It allows
the hard-drive & cd-rom to run without accessing the cpu allowing
faster throughput(usually).If your bios was made before 6/2000 then
I would leave DMA off.

DMA has been around for years. I would not use 6/2000 as a cutoff date for turning it off. In fact, I can't think of a reason to ever turn it off unless a device doesn't work properly with it on. DMA allows data to be read from or written to drives without involving the CPU, which frees the CPU up for other operations. It greatly reduces the risk of buffer underruns.