指南:系统原则 | Guide: System principles 目录 1.系统原则 | 1. System Principles 2.错误记录 | 2. Error Logging 3.创建和升级目标系统 | 3. Creating and Upgrading a Target System 4. Erlang / OTP更改时升级 | 4. Upgrade when Erlang/OTP has Changed 5.版本 | 5. Versions