c est 1.5 et 3 Gb/s, et en plus c est pas le cas...
"Bah c´est simplement le nom de la norme... Pas de gros avantage que ce soit I ou II... Bon il y a aussi l´hot plug entre autre, il n´y a pas que c´est trois là!!!
What´s the real difference between SATA I and SATA II? SATA II is better suited for enterprise environments because of three important features, port multipliers, port selectors and native command queuing.
Port multipliers: In SATA I, parallel ATA drives had to be configured as master and slave and daisy-chained from each controller. The port multiplier spec from the Serial ATA Working Group allows up to 15 drives to be connected to a SATA controller via a port multiplier. Although this is far less than the number of drives that can be connected using Fibre Channel or Serial Attached SCSI (SAS), this will make it much easier to build disk enclosures using SATA drives.
Port selectors: Port selectors will allow two hosts to be connected to one drive. This is useful because it creates a redundant connection to the disk drive. In this way if one of the hosts has a failure, the second host, acting as a spare, can take over and access to the storage is maintained. This sort of redundancy is essential for enterprise environments.
Native command queuing: Native command queuing will improve the performance and efficiency of SATA II drives. Normally commands will arrive at a disk to read or write from different locations on the disk. When commands are executed in the order they arrive, a great deal of mechanical overhead is created when the read/write head is constantly being repositioned. SATA II drives will use an algorithm to determine the most efficient order to execute commands, which creates the least mechanical overhead. In this way native command queuing will improve the performance of SATA II.
Each of these additions to SATA will make it much more useful to enterprise data centers. However, these improvements to SATA don´t mean that enterprises will forget about SCSI and Fibre Channel and run into the arms of SATA. SCSI, Fibre Channel, and soon SAS, will still be the primary candidates for mission critical storage. Rather SATA will be used to solve other problems in enterprise storage, notably nearline storage.
Dispelling the Confusion: SATA II does not mean 3Gb/s
The term SATA II has grown in popularity as the moniker for the SATA 3Gb/s data transfer rate, causing great confusion with customers because, quite simply, it’s a misnomer.
The first step toward a better understanding of SATA is to know that SATA II is not the brand name for SATA’s 3Gb/s data transfer rate, but the name of the organization formed to author the SATA specifications. The group has since changed names, to the Serial ATA International Organization, or SATA-IO.
The 3Gb/s capability is just one of many defined by the former SATA II committee, but because it is among the most prominent features, 3Gb/s has become synonymous with SATA II. Hence, the source of the confusion.