On Sunday 28 December 2008 9:15 am, Greg Freemyer wrote:
On Sat, Dec 27, 2008 at 9:47 PM, Robert Paulsen
wrote: <snip> MY QUESTION:
The card is a 32-bit/33mhz PCI card (not PCI express) and claims to support 3.0Gbps. I thought that the PCI bus was not fast enough for 3.0Gbps and PCI express was required. Am I missing something? Am I simply wrong about the PCI bus' capabilities?
Bob
In reality there are 2 basic modes: Sata-1 and Sata-2. The most obvious difference is speed, but sata-2 offers some other features you might want to use.
For some reason, controller / disk manufacturers like to claim 3Gbs capability, when they really mean Sata-2 compatibility. ie. Not only "faster" but also other enhanced features.
As to speed on PCI, I think you are right. The only thing you really get is access to the other enhanced features. (ie. NCQ for one is only supported on SATA-2 drives.)
Also, a single sata drive can NOT saturate a 1.5Gbs connection, so more speed is not needed for point to point connections.
Sata has something called PMP. aiui, it is like a sata-hub. You connect one side to your controller and the other side to a number of different sata-drives. With PMPs in use the controller / hub connection can saturate a 1.5Gbs link, so you would want to use 3.0Gbs for that config.
I am confused by all of the above. Both the drive and that card claim 3Gbps. Are you saying that the drive really doesn't (can't?) xfer data at 3Gbps? You say that I am right (presumably about PCI bus not supporting 3Gbps), but then seem to imply the PCI bus will support multiple drives that add up to over 1.5Gbps? Sorry for being dense! Bob -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org