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 with no adverse effects on battery life.[6]

In traditional low-power modes, SATA link still needs to remain powered on to allow the device to receive a wake-up command. With DevSlp, rarely used 3.3 V pins of the SATA power plug will be used for the DevSlp signal instead of providing 3.3 V power. This signal can wake up the drive, and it will allow SATA link to be shut down, reducing further the power consumption.[7]

Due to the way they work, DevSleep-enabled drives may not be suitable for most desktop PCs and some notebooks with the 3.3 V voltage present in their SATA power connectors; the presence of 3.3 V results in DevSleep-enabled drives remaining in DevSlp state.[7] An incompatibility between a desktop mainboard and a SATA SSD may be resolved by disabling the DevSleep feature using a power connector adapter that does not pass the +3.3 V line.

References

  1. ↑ Niels Broekhuijsen. "Tom's Hardware review of BIWIN announcement of using DevSlp". Tom's Hardware.
  2. ↑ Christopher Ryan. "Tom's Hardware review of the Transcend SSD340". Tom's Hardware.
  3. ↑ Kevin Parrish. "Toms Hardware DevSlp initiative". Tom's Hardware.
  4. ↑ "StorageReview coverage of DevSlp standard".
  5. ↑ "Techspot review of feature". TechSpot.
  6. ↑ Brad Chacos (6 January 2012). "New Power-Saving DevSleep Feature Added To SATA Specification". maximumpc.com. Retrieved 8 July 2015.
  7. 1 2 "c′t Hotline SSD mit "Devsleep"-Funktion (German article)". c't. 25 June 2014.


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