WASHINGTON - Computer scientists at UC San Diego and Microsoft Research have created a device that will put computers in a doze, which could mean energy savings of 60 to 80 per cent.

The experts have developed a plug-and-play hardware prototype for personal computers that induces a new energy saving state known as "sleep talking."

Normally PCs can be in either awake mode-where they consume power even if they are not being used, or in a low power sleep mode-where they save substantial power but are essentially inactive and unresponsive to network traffic. The new sleep talking state provides much of the energy savings of sleep mode and some of the network-and-Internet-connected convenience of awake mode.

UC San Diego computer science Ph.D. student Yuvraj Agarwal presented this work on April 23, 2009 at the USENIX Symposium on Networked Systems Design and Implementation (NSDI 2009). Computer scientists at UC San Diego and Microsoft Research in Redmond, Washington and Cambridge, UK collaborated on this project and the NSDI 2009 paper, "Somniloquy: Augmenting Network Interfaces to Reduce PC Energy Usage."

"Large numbers of people keep their PCs in awake mode even though the PCs are relatively idle for long blocks of time because they want to stay connected to an internal network or the Internet or both," said Agarwal.

"I realized that most of the tasks that people keep their computers on for-like ensuring remote access and availability for virus scans and backup, maintaining presence on instant messaging (IM) networks, being available for incoming voice-over-IP (VoIP) calls, and file sharing and downloading-can be achieved at much lower power-use levels than regular awake mode," said Agarwal.

Following the realization, team built a small USB-connected hardware and software plug-in system that allows a PC to remain in sleep mode while continuing to maintain network presence and run well-defined application functions. It supports instant messaging applications, VoIP, large background web downloads, peer-to-peer file sharing networks such as BitTorrent, and remote access.

The computer scientists named their system Somniloquy, which means "the act or habit of talking in one's sleep." In fact, the system allows a PC to appear to "say" to other hosts on the network, "I'm awake and I can perform non-power-intensive tasks"-even though the PC is in sleep mode. If more computational muscle or resources present on the PC such as stored files are required, Somniloquy wakes up the PC.

The researchers evaluated Somniloquy in various settings and say that it consumes 11 to 24 times less power than a PC in idle state, which could translate to energy savings of 60 to 80 percent depending on their use model. (ANI)