Relation between DMA and AHCI technologies

[Aariyan]

Hello Everybody,
AHCI is defined as "a data movement engine between Memory and SATA devices". So DMA also acts as a "data movement engine between memory and storage devices". So, Is AHCI is enhanced version of DMA? Can anybody give me more clarification on this?

Thanks
Aariyan

[Touchclarity]

I believe that AHCI enables NCQ support as well as hot-plug capability, Performace difference is negligible..

Steve..

[Doomer]

DMA is a protocol
AHCI is an interface

They not comparable

[Vulcan]

@Aariyan,

I agree with Doomer. Here are a few more comments...

AHCI is defined as "a data movement engine between Memory and SATA devices".

No it isn't. You don't explain the source of this (misinformed) definition, but I suggest you read some more about AHCI, and read (at least some) of the specification itself:
http://www.intel.com/technology/serialata/ahci.htm
http://download.intel.com/technology/se ... rev1_3.pdf
A useful starting point for you, would be section 1.7 "Theory of Operation" in the AHCI spec v1.3 that I linked above.

So, Is AHCI is enhanced version of DMA?

No.

Can anybody give me more clarification on this?

As an example: For part of its operation, an AHCI HBA uses DMA to access data in system memory, acting as a PCI bus master. However, as you will read in the specification, the AHCI specification defines much more than this.