DevSlp
DevSlp or DevSleep (sometimes referred to as device sleep or SATA DEVSLP) is a feature in some SATA devices which allows them to go into a low power "device sleep" mode when sent the appropriate signal, which uses one or two orders of magnitude less power than a traditional idle (about 5 mW,[1] but some drives can get as low as 2.5 mW[2]). The feature was introduced by SanDisk[3] in a partnership with Intel.[4] Some think that the initiative could make laptops feel like they power on basically instantaneously,[5] while others state that this means that laptops can stay on all the time, and always be available without an adverse affect on battery life.[6]
Working principle:
At the traditional low power modes the SATA link must still be powered on, for receiving the wake up command. Now the rarely used 3.3V pins of the SATA power plug will be used for the DevSleep signal instead of 3.3V power. This signal will shut down the SATA link to reduce the energy and can wake up the drive.[7]
Disadvantage:
Drives with DevSleep are not suitable for most desktop PCs and some notebooks with 3.3V at the SATA power plug. This 3.3V leads to not starting up the drive, because the drive remains in DevSleep state.[7]
References
- ^ Tom's Hardware review of BIWIN announcement of using DevSlp
- ^ Tom's Hardware review of the Transcend SSD340
- ^ Toms Hardware DevSlp initative
- ^ StorageReview coverage of DevSlp standard
- ^ Techspot review of feature
- ^ MaximumPC review of feature
- ^ a b c′t Hotline SSD mit "Devsleep"-Funktion (German article)
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