The curious thing about this feature starts from its name. DevS sleep, DevSlp or SATA DEVSLPIn any of the three ways this feature can be named and although it is the only original one, jargon has done its job and currently two official variations as far as this technology is allowed.
DevS sleep was introduced with an overview of SATA 3.2
It was August 8, 2013 that the Consortium known as the seri ATA International Organization, also known as SATA-IO
In this review, short but sharp, it was explained in a brief and straightforward way what one of the new features of future HDDs and SSDs will mean: Sleep.
To truly quote the Consortium: DevS sleep is a very low power management environment, where the unit shuts down almost completely to meet the needs of a new "compact, durable" computer for mobile devices, such as Ultrabook.
As we can see, it is very common even though it is the Consortium that owns the SATA standard, so it later became more and more detailed: it is a stand-alone device, either an HDD or an SSD, which lowers its capacity, because this is 5 mW and 2.5 mW
This leaves two separate regimes known as Partial or Sleep Mode, which the Host or device can now use directly by moving commands. PM_REQ_P and PM-REQ_S.
The intermediate state between sleep and normal is off
This situation, to put it simply, is the latest mode for existing disks. It is not a complete sleep state such as a normal hibernation, or a normal shutdown state, but an intermediate state that has absolutely no latency and reduces consumption significantly.
To accomplish this, SATA-IO had to redefine the deputy power supply 3.3 volts, where it introduces the DEVSLP signal. This organization allowed its approval without needing a change to Hardware, in the simplest and only way after that BIOS / UEFI update support well.
When activated, the controller AHCI It will show support in the skill register, while the device, whether HDD or SSD, notifies that it is compatible with DevS sleep. This way they both interact and make no mistake with Slumber or Parity state, being able to benefit from the benefits of this new technology.