Nell/Architecture

From OLPC
Jump to navigation Jump to search

Nell consists of several modules. They're not independent; there are defined API interactions between them. (Listing them here doesn't mean that we're going to design and implement each top-down before putting any activities together -- I think being very demo-focused and starting right at the user-visible layer is still a fine idea.)

Nothing here is final yet; still at the brainstorming stage.

Modules

Avatar services

  • Stores user's name, chosen avatar appearance, avatar's friends, preferences.
  • How literate is this user?
  • What kind of learning style (visual, puzzle solving, blackboard) do they learn from best/prefer?
  • Like Sugar's Journal, this should provide an opportunity for reflection on (and replay of) past experiences.

Tech tree

Narrative model

  • Contains metadata visible to the tech tree about what kind of activity this is.
  • The prerequisites for an activity/narrative chunk aren't limited just to which activities/story chunks have been completed -- they might also depend on outcomes from activities, stored in Avatar Services. This provides for a coherent narrative arc, with the side effect that the user gets to hear stories that are more like the stories they've enjoyed and chosen to go deeper into previously.
  • Activities must be extremely pluggable. The same activity (painting, music creation, etc) may have many different narratives available -- some with different languages, teaching styles, some may have been written by teachers and some by kids.
  • The narrative model defines possible outcomes from this activity, and passes them down to Avatar Services as they're made.
  • Achievements are types of outcomes, too.

Activity view

  • Takes an narrative model and renders the story on-screen, incorporating partially scripted interactions with an underlying Activity. At interesting decision points or events, evokes outcomes to the model. Much of the story logic is probably embedded in the view. The view hooks into avatar services to decide how best to present itself. The view hooks into the underlying activity to make special functions available -- for example, to present a piano or a drawing canvas or turtle programming environment or a cut scene.

Story creator

  • We'll need a tool that can author an activity model and view. It should allow the author to choose prerequisites, define outcomes, and have access to any prior outcomes it's interested in when deciding on a narrative.

Open questions

  • Is the activity model/view split actually interesting, or should everything other than prerequisites just happen inside the view? (Maybe this should be decided after a few demo activities exist.)