The concept of RAF is proposed to demonstrate the possibility of developing interruptible applications. A RAF application is loosely decoupled into multiple descriptors with channels to maintain the data stream. The structure could be described via Directed Cyclic Graph. Each descriptor could run on different devices connected via wireguard

Each descriptor should implement the retain/restore primitives to maintain its own state, e.g., I/O devices, file system, graphics buffer, network connection, etc.

The channel is also implemented as a descriptor which is responsible to share data between the descriptors. The design of channel model is multi-fold.

Subscriptions:

• shared (default): on-demand uni/bi-direction
• propagate: best-effort uni/bi-direction
• tether: real-time bi-direction
• stream: uni-direction with sampling frequency

Efficiency:

• intra-process channel should use shared memory space in stack;
• inter-process channel may use dual multiprocessing.Queue;
• inter-remote channel may use dual UDP sockets.

Reliability:

• fec: FEC-encoded correction
• lossy: lossy compression for multimedia buffer

1. PyRAF is not a P2P framework, the APP is hosted by the device with the Yggdrasil;
2. Yggdrasil is composed of ChannelDescriptors (as truss) and other BaseDescriptors (assembled on truss);
3. PyRAF enables a high-level garbage collection. The retain/restore cycle can drain the memory leak of the descriptors at the cost of memory overhead.