Native Command Queuing - NCQ Newbie's Questions

[Crey]

Well, other a mix up with the CPU that I hope will get resolved in a couple days, I'm almost ready to assemble my new computer. However, I've been doing some thinking about my hard drives. I have an Asus A8N-SLI motherboard and two Seagate 160 gig SATA drives with NCQ. Now, I assume the A8N motherboard supports NCQ. With all the boasting of SATA II, it had better support NCQ. But do I need to turn NCQ on in the BIOS or something? Or will this just be something that is detected and used automatically? Is there any way to tell that it's working? I've been searching around for an article about NCQ, but I haven't read anything yet that gives me my answers (or if it did, I missed it). If someone could point me to a helpful article or if someone just knows the answer, I'd be much appreciative.

Thanks in advance,
Crey

 

[RichPLS]

Good question...
I don't know how to check this myself, I have a Raptor 74 gig, and I suppose mine is working?!?

In case of TCQ for SCSI, several commands are marked with a so called tag. A hard drive treats the commands in a certain way, according to their tag:
1: Ordered
Those commands are executed in the same order as they arrive.
2: Head of queue
This command gets executed right after the current command.
3: Simple
In that case the hard disk controls the sequence of all commands in queue. This makes sense, since the hard drive knows its own characteristics (cylinder/heads/sections) best.

Native (NCQ) works just like the "simple" mode of (TCQ), but doesn't offer the other two options.

Command Queuing Puts incoming commands in a line. The length of this line is known as the queue depth. The maximum queue depth for NCQ is 32 commands per initiator. In theory, 216 tags are possible for TCQ, but this has never been used. In real life applications, the common queue depth is most often 64 commands.

Last but not least, there is one more feature that NCQ provides, which TCQ does not. Called 'Out of Order Data,' this feature allows a drive to deliver parts of a demanded data package only, which reduces the search time even more.


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[Merman]

http://www.tomshardware.com/motherboard/20041020/nforce4-04.html

 

[JustysRule]

Well does NCQ and SATA II require a special motherboard, or will it work with a normal SATA motherboard?

 

[jammydodger]

NCQ requires that the SATA controller supports it. The only onboard NCQ compatible controller I know of is Intels ICH6.