ANTS 1.2 already provided for the use of different implementations of services upon which the ANTS run-time system relies. For instance, subclasses of the abstract base class Channel provided implementations of send() and receive() that were specific to a particular transport, such as UDP or Ethernet. We believe we improved upon that already existing separation.
We made the separation between ANTS run-time and the services
it uses explicit by putting the services in a separate package,
called nodeos. It should be noted that this separation is
nowhere near complete: at this time, only two services have been
extracted. These
services are the dispatching of incoming packets and the scheduling
of outgoing packets.
In addition, the Node OS package provides a buffer type upon which
ANTS bases the Xdr streams it uses for encoding and decoding.
In the future, this package will be enriched with services to control the CPU and memory usage of different protocols. These services are currently under development.
The current implementation is in user mode, but all kinds of implementations are conceivable--essentially, the Node OS package is responsible for wrapping the abstractions provided by the actual Node OS and presenting them to the ANTS run-time. For instance, a Scout-based implementation might use message trees to implement buffers and paths and their demultiplexing capabilities to implement the dispatch of packets.