Washington (IANS): Personal computers may soon save large amounts of energy by "sleep talking".

Doctoral researcher Yuvraj Agarwal of the University of California San Diego (UCSD) in collaboration with computer scientists has created a plug-and-play hardware prototype for personal computers (PCs) that induces a new energy saving state known as "sleep talking".

Normally PCs can be in 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.

"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, who did his engineering degree from Pune University in June 2001.

"I realised 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 this realisation, the team built a small 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 say their system can easily be extended to support other applications.

The scientists named their system Somniloquy, which means "the act or habit of talking in one's sleep", according to an UCSD release.

"Reducing energy consumed by wall-powered devices, especially computing equipment, offers a huge opportunity to save money and reduce greenhouse gasses," said Agarwal.