The Serial ATA International Organisation has revealed the specifications of SATA revision 3.2. This new version adopts recent market developments, such as SATA Express and the M.2 form factor. It also pays attention to hybrid drives and power management. The standard ensures all manufacturer will use the same dimensions and connectors, thus guaranteeing compatibility.
SATA Express was officially introduced in January and combines SATA and PCI-Express, allowing for greater performance. Using two PCI-Express 3.0 lanes, the theoretical maximum speed is 2 GByte/s. This is of particular interest for SSDs and so-called SSHDs, the hybrid drives. Devices whose bottleneck isn't the SATA-interface, including optical drives and traditional hard drives, will keep using the regular SATA-interface in revision 3.2.
In addition to these performance improvements, the M.2 form factor has been officially adopted into the standard. This will make it easier to add all sorts of functionality to slim devices such as tablets and notebooks. M.2 is even smaller than mSATA and can vary in length: 42, 60, 80 or 110 millimetres. The standard only specifies the interface and dimensions, manufacturer can develop their own applications, such as WiFi, WWAN, USB, PCI-Express and of course SATA.
The Crucial M500 in M.2 form factor
microSSD has also been added as a feature, allowing developers to create embedded SSD solutions with a single chip. Universal Storage Module (USM) was already part of the standard but is now also available as USM Slim, allowing removable and expandable storage to slim down even further. An important development in the field of energy efficiency is DevSleep, a special sleep mode for hard drives and SSDs. Transitional Energy Reporting also assists in decreasing power consumption: a drive can now provide more detailed information about its status, allowing the host to make more educated power management decisions. Lastly, the recovery speed of RAID-configurations has been increased thanks to Rebuild Assist.
As mentioned, the SATA-organisation has also thought of hybrid drives: a host can now provide information on data-caching to a drive, potentially leading to better performance.