One Laptop Per Child (OLPC) has taken another step forward in its mission to make low-cost notebooks available to children in developing nations, unveiling a UI (user interface) purpose-built for the machines.

Known by the code name Sugar, the open-source UI publicly announced Wednesday was developed by OLPC in conjunction with Linux distribution vendor Red Hat Inc. and design firm Pentagram. The organizations' combined 10-person design team focused on creating a UI that could be easily used by children with little or no computing experience.

Currently, Sugar is still "a work in progress," according to Christopher Blizzard, software team lead for OLPC at Red Hat. "The code's working reasonably well, but there's a lot of polish we need to do."

Over the next couple of months, OLPC plans to ramp up the numbers of its laptops in countries including Argentina, Brazil and Nigeria from the current 10 to 50 devices per country into the "low thousands," Blizzard said. As children start using the laptops, OLPC is looking to incorporate feedback on Sugar into the design process. "We're taking the tack -- release early, release often," he added.

The Sugar UI features four main views -- home, friends, neighborhood and activity -- and uses stick figure icons to denote the individual user and other children on the network and other icons to indicate particular activities such as a globe for Web browsing or a palette for an art project.

"We're trying to build something that is collaborative first," Blizzard said. Simplicity and accessibility are important factors, but the design team was also keen not to limit the UI's capabilities. "Walter's take is it doesn't have a ceiling, but it has a very solid floor," Blizzard said, referring to OLPC President Walter Bender.

Starting from the home view where they can specify user preferences like color, a child can then move to the friends view to see which of their friends are on the network and what they're doing. They can also chat with them. The neighborhood view shows everyone connected to the mesh network and the activities they're engaged in. At any point, the child can also choose to join in with group activities.

Each laptop can act as a node in a mesh peer-to-peer ad hoc network, so that if one laptop is directly accessing the Internet, when other machines in the network power on, they can share that single online connection.

The activity view allows a child to focus on a specific activity using the laptop's full-screen mode. There's also a journal view that can be thought of as another activity, where a child can see what he or she has created on the desktop, save and add to that content, and share it with friends.

Around any of the views is a frame equivalent to the menu bar on more traditional computer user interfaces. The child can click on people, places and things around the right, left and top sides of the frame, while the bottom side is reserved for accessing activities. There's also a context-sensitive search bar on the top of the frame so that the child can easily locate things on the desktop.

The laptop's operating system is a scaled-down version of Red Hat's Fedora Core 6 Linux distribution. Sugar also includes a Web browser based on the Mozilla Foundation's Gecko rendering engine.