dao-os-docs/src/specifications/tech_overview.md

Technical Overview

This document provides a high-level overview of the architecture, core technologies, and guiding principles for developers looking to build on or contribute to the Dao OS ecosystem.

Guiding Technical Principles

Our engineering decisions are guided by a set of core principles to ensure the system is robust, portable, and open.

• Web-Native & Portable: We leverage technologies born from the web (like WebAssembly) to create a single, portable core that can run anywhere—on desktops, mobile phones, servers, and in the browser.
• Polyglotism via WASM: The core logic (Meta Unit) is compiled to WebAssembly (WASM). This allows "Avatars" to be written in any language (Rust, Swift, Kotlin, TypeScript, Go, etc.) that can host a WASM runtime, creating a truly diverse ecosystem.
• API-First: The interaction between the core Meta Unit and the host Avatar is defined by a strict, versioned API contract. This decouples development and allows for independent evolution.
• Security-First: We employ best-in-class cryptographic protocols and a "principle of least privilege" design. Security is not an afterthought; it is a prerequisite.
• FOSS (Free and Open Source Software): The entire core protocol and reference implementations are open source to foster transparency, community trust, and collaborative innovation.

The Core Components: A Developer's View

From a developer's perspective, the system consists of two main parts that interact via a well-defined boundary.

1. The Meta Unit (WASM Module): This is the portable, logical core of the system. It is a stateful, single-instance module developed primarily in Rust for its performance and safety guarantees. It contains all the business logic for data management, AI, and peer-to-peer coordination, but it has no direct access to the outside world.

2. The Avatar (Native Host): This is the native application or runtime environment that "hosts" the Meta Unit. Its primary responsibilities are:

   • Providing a WASM runtime to load and execute the Meta Unit.
   • Providing a User Interface (for Client Avatars).
   • Acting as a bridge to the host operating system, providing access to the filesystem, network, and other system resources.

The API Contract: The WASM Interface

The communication between the Avatar and the Meta Unit follows a clear, bidirectional API contract, similar in spirit to WASI (WebAssembly System Interface).

• yuan_* (Exports from Meta Unit): The Meta Unit exposes a set of functions that the Avatar can call. The primary entry point is yuan_handle_request, which takes a structured request from the Avatar and processes it.

• avatar_* (Imports into Meta Unit): The Meta Unit declares a set of functions that it needs the Avatar host to provide. These functions are its only window to the outside world, allowing it to request actions like logging a message (avatar_log) or making a network request (avatar_net_request).

• Data Serialization: To pass complex data structures across the WASM memory boundary efficiently and safely, we use Protocol Buffers (Protobuf). Data is serialized into a byte buffer, passed as a pointer and length, and then deserialized on the other side.

Key Technologies & Protocols

Category	Technology / Protocol	Purpose
Core Logic	Rust / WebAssembly (WASM)	Performance, safety, and ultimate portability.
P2P Networking	libp2p	Modular peer discovery (DHT), transport, and secure channels.
Data Synchronization	CRDTs (Conflict-Free Replicated Data Types)	Ensuring eventual consistency across Avatars without a central server.
Identity	DID & VC (Decentralized Identifiers & Verifiable Credentials)	Sovereign identity and interoperable, cryptographic trust.
Data Serialization	Protocol Buffers (Protobuf)	Efficient, language-agnostic data structures for APIs.

This modular, open-protocol-based stack is designed for security, portability, and, most importantly, community contribution.