High Security for $100 Laptop
Wired has an interesting piece this morning explaining how security will be implemented in OLPC notebooks. Instead of using traditional security features such as a firewall or an anti-virus, "$100" laptops will apparently protect themselves from intruders / malicious code by running each of their applications into separate, independant virtual machines.
Krstic's system, known as the BitFrost platform, has only one user prompt (turning on the camera) and imposes limits on every program's powers. Under BitFrost, every program runs in its own virtual machine with a limited set of permissions. Thus a picture viewer can't access the web, so even if a hacker comes up with an exploit that lets him control the program, he couldn't use it to grab all the photos on the laptop and upload them to the internet.