Greening PCs with 'Sleep Talking'

Photo: Yuvraj Agarwal who came up with the idea of a "sleep talking" state.

Computer scientists at UC San Diego and Microsoft Research have created a plug-and-play hardware prototype for personal computers that induces a new energy saving state known as "sleep talking."

We are all pretty much familiar with the PCs' sleep mode - a low power state where the computer is essentially inactive and unresponsive to network traffic. In the new "sleep talking" state, there is much the same kind of energy saving as found in sleep mode, but it allows the PC to maintain some of the network-and-Internet-connectivity of awake mode.

"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, one of the key developers, in a news statement. "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."

Photo: The gumstix-based Somniloquy prototype - Wired-1NIC version.

Following this realization, his 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. They called their system Somniloquy, which means "the act or habit of talking in one's sleep."

The goal of Somniloquy is to encourage people to put their PCs in sleep mode more often. "Reducing energy consumed by wall-powered devices, especially computing equipment, offers a huge opportunity to save money and reduce greenhouse gasses," said Agarwal.

The researchers evaluated Somniloquy in various settings and say that it consumes 11 to 24 times less power than a PC in idle state, according to the news statement. This, they say, could translate to energy savings of 60 to 80 percent.

The current prototypes work for desktops and laptops, over wired and wireless networks, and are incrementally deployable on systems with an existing network interface. It does not require any changes to the operating system on the PC, to routers or other network infrastructure, or to remote application servers.

In the future, Somniloquy could be incorporated into the network interface card on new PCs, which would eliminate the need for the prototype's external USB plug-in hardware.