The revolutionary hardware design was hard enough, but the software goals are incredibly ambitious, particularly in the areas of security and long-term user data persistence within a very small space. Right now the permanent data store is 1Gb of flash RAM, and that stores the OS and apps as well. Every user file will have built-in versioning and they still have to figure out how to intelligently remove old documents and versions that are no longer needed. They want simple, near automated, and encrypted backups to school servers. Security with no passwords, no signed code, the OS runs with the assuption that any running app could be “evil”…as massive deployments of uniform systems these machines could become targets for worms and for use in DDoS attacks.
Another great talk I saw recently was a dissection of the XBOX’s security system and its compromise. The presenter does a particularly great job of entertainingly diagramming and describing the machine-level ideas behind the attacks without assuming much knowledge in the area.