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SATA standards have gone through some upheaval recently. The governing body for the SATA standards has changed names, and there is plenty of confusion in the market place (much of it created by HD makers hijacking standards for marketing gain) on what SATA terms mean what. Here's some more info, which will hopefully cut through the fog.
The Serial ATA (which, if you ever wondered, ATA stands for AT Attachment, and AT in turn stands for Advanced Technology, a throwback to the IBM XT/AT PC days of the 1980s) governing body is, at present, the SATA International Organization. They have a website here. They work with storage vendors to develop, ratify, and document SATA standards and features. This is all well and good for consumers - it assures that a drive from maker x will work with a controller from vendor n, and that drives from makers x and y will interface equally well with a given controller. This is the minimum standard that drives must meet to be certified as an SATA device - they must use a common protocol and common cables/connections, and all SATA devices must meet these standards to operate as an SATA device.
The SATA-IO has standardized extra features for this new interface, such as hot plug support, native command queuing (NCQ), port multipliers, higher 3 gbps interface transfer rates and other features outlined in this document. However, there is a catch here, and this is where the confusion begins. These standards are only a framework for compatibility, not rigid requirements. Neither drive nor host makers are required to implement any of these advanced features. They may mix and match features to suit the needs of their customers. The only requirement is that they must follow the standards should they desire to implement those features. Once again, the goal of these standards is to ensure interoperability between products from the myriad of vendors out there, not force every SATA device to have a common feature set. SATA-IO also mandates backward comaptibility so that drives with advanced features will work with basic controllers and vice versa, the advanced features are simply disabled. So, drive and host makers are free to implement - or leave out - any of these advanced, or if you will, "second generation" features. To make the confusion over these features even worse, the SATA-IO's predecessor, shortly before its demise, developed a standard called "SATA-II" that incorporated many of the same features seen in the new SATA-IO's standards. These new SATA-IO standards are referred to, as a suite, as SATA-3G. This means that there are many "SATA-II" drives and hosts on the market that do NOT SUPPORT all of the SATA-3G features.
What does this mean to you? This means that a drive (or host controller) that is advertised as being "SATA-II" doesn't necessarily (and the vast majority of the time does not) implement all of the SATA-IO's next generation features and standards. The maker may implement as few as one of the new features and call it a second generation SATA product. When shopping for SATA products, if you require one of the new features, you need to make sure that all devices involved, both hosts and drives, explicitly support that feature.
Furthermore, none of these new features will improve the mechanical performance of a hard drive. You will see the same transfer rates and seek times with a 3gbps NCQ drive as the same drive running @ 1.5gbps without NCQ. Burst transfer rates will be higher at 3 gbps, but their impact on actual application level performance is small at most.
Support for NCQ and the higher 3gbps transfer rates are common on many newer drives and hosts. However, some of the more exciting technologies, such as port multipliers, haven't gained broad market acceptance yet. When the market is ready for these features and products that support them become available, you can be sure that the SATA-IO standards will ensure a smooth transition to the new features (in theory at least)
The Serial ATA (which, if you ever wondered, ATA stands for AT Attachment, and AT in turn stands for Advanced Technology, a throwback to the IBM XT/AT PC days of the 1980s) governing body is, at present, the SATA International Organization. They have a website here. They work with storage vendors to develop, ratify, and document SATA standards and features. This is all well and good for consumers - it assures that a drive from maker x will work with a controller from vendor n, and that drives from makers x and y will interface equally well with a given controller. This is the minimum standard that drives must meet to be certified as an SATA device - they must use a common protocol and common cables/connections, and all SATA devices must meet these standards to operate as an SATA device.
The SATA-IO has standardized extra features for this new interface, such as hot plug support, native command queuing (NCQ), port multipliers, higher 3 gbps interface transfer rates and other features outlined in this document. However, there is a catch here, and this is where the confusion begins. These standards are only a framework for compatibility, not rigid requirements. Neither drive nor host makers are required to implement any of these advanced features. They may mix and match features to suit the needs of their customers. The only requirement is that they must follow the standards should they desire to implement those features. Once again, the goal of these standards is to ensure interoperability between products from the myriad of vendors out there, not force every SATA device to have a common feature set. SATA-IO also mandates backward comaptibility so that drives with advanced features will work with basic controllers and vice versa, the advanced features are simply disabled. So, drive and host makers are free to implement - or leave out - any of these advanced, or if you will, "second generation" features. To make the confusion over these features even worse, the SATA-IO's predecessor, shortly before its demise, developed a standard called "SATA-II" that incorporated many of the same features seen in the new SATA-IO's standards. These new SATA-IO standards are referred to, as a suite, as SATA-3G. This means that there are many "SATA-II" drives and hosts on the market that do NOT SUPPORT all of the SATA-3G features.
What does this mean to you? This means that a drive (or host controller) that is advertised as being "SATA-II" doesn't necessarily (and the vast majority of the time does not) implement all of the SATA-IO's next generation features and standards. The maker may implement as few as one of the new features and call it a second generation SATA product. When shopping for SATA products, if you require one of the new features, you need to make sure that all devices involved, both hosts and drives, explicitly support that feature.
Furthermore, none of these new features will improve the mechanical performance of a hard drive. You will see the same transfer rates and seek times with a 3gbps NCQ drive as the same drive running @ 1.5gbps without NCQ. Burst transfer rates will be higher at 3 gbps, but their impact on actual application level performance is small at most.
Support for NCQ and the higher 3gbps transfer rates are common on many newer drives and hosts. However, some of the more exciting technologies, such as port multipliers, haven't gained broad market acceptance yet. When the market is ready for these features and products that support them become available, you can be sure that the SATA-IO standards will ensure a smooth transition to the new features (in theory at least)