A start-up has developed  a device designed to seamlessly connect network attached storage to online backup services such as Amazon's S3 Simple Storage Service.

Designed for small businesses and home users, the vendor Ctera's product turns any USB storage drive into a file server that automatically backs up to an online storage service, even when the user's computer is turned off.

Ctera calls its approach "cloud attached storage" and says its first product will be the CloudPlug, a small device that connects to a user's Ethernet router and USB drive. Files on the USB drive can be shared with anyone else on the network, while integration with online backup services will let mall business users reduce internal storage needs, Ctera said.

Co-founder and CEO Liran Eshel said CloudPlug features easy-to-use management tools, hardware-based encryption, and de-duplication to reduce the amount of data that must be backed up to the cloud. He's not saying when Ctera's technology will be on the market, except that it will be sold through Internet service providers and managed service providers beginning sometime in 2009.

Customers would likely be charged monthly fees, anywhere from tens to hundreds of dollars each billing cycle depending on the amount of data. Ctera's architecture is platform-independent so customers should be able to use any cloud storage provider they want, he said.

Eshel and co-founder Zohar Kaufman formerly led SofaWare Technologies, a Check Point company that makes Internet security products for small businesses and branch offices.