Table of Contents Namespace Linking Namespaces Device Services Meadow Services Processes

• A Meadow namespace should provide a namespace (i.e. name-? table) of devices and services.
• The naming of devices should be independent of the transport address which can change over time.
• A namespace coincides with the security-enforced domain.
• A namespace is maintained by a special device called NAMESERVER. Any device which runs name service is a NAMESERVER. Every device must have at least one NAMESERVER.

• Namespace can be linked to form a larger namespace.
• After two namespaces, say A and B, are linked, a device in one namespace can access a device in another namespace.
  • Devices in namespace A can access any device in namespace B by using a prefix "B:".
  • ANALOGY: UNIX hierarchical file system
• Two linked namespace can be unliked whenever it's not necessary to be linked.

• A device should be able to export three services to the outside services.
  • property service
  • event generation
  • RPC
• A device should provide a way to modify its own behavior.
  • Internally, this is a reactor but users don't need to know reactors.
  • To users, it's just adding callback to an event.
  • add_callback(event, (*fun)());
• Service must be deployable statically or dynamically.

• Name service
  • Any device that provides name service is a NAMESERVER.
  • Name service is just a set of RPC functions used to maintain namespace.
  • NAMESERVER maintains (device, addr) and (linked-namespace-nameserver, addr)

• A process is defined as an execution of event-reaction sequence.
• The lifetime of a process begins with a firing of a root event and ends until all the reactors fired by the event instance finishes their execution.
• Should a process be a singleton (like Verilog process) or a forked thread?
• A process call chain is defined as the sequence of function calls and/or event-reactions, starting with an event instance which wakes up a process. The first event must be either a timer event or an external event injected from outside (e.g. user's touchscreen input).
• A method for killing all related processes in a process call chain must be provided.