1e41f4b71Sopenharmony_ci# Time and Time Zone Subsystem 2e41f4b71Sopenharmony_ci 3e41f4b71Sopenharmony_ci## Introduction 4e41f4b71Sopenharmony_ci 5e41f4b71Sopenharmony_ci The time and time zone subsystem provides OpenHarmony with the capability of managing the system time, time zone, and timing. 6e41f4b71Sopenharmony_ci 7e41f4b71Sopenharmony_ci- **Time and time zone management** 8e41f4b71Sopenharmony_ci 9e41f4b71Sopenharmony_ci Manages the system time and time zone in a unified manner, including setting and obtaining the system time, date, and time zone, and obtaining the system startup time. 10e41f4b71Sopenharmony_ci 11e41f4b71Sopenharmony_ci- **Timing management** 12e41f4b71Sopenharmony_ci 13e41f4b71Sopenharmony_ci Provides the system timer capability, including creating, starting, stopping, and destroying timers. There are three types of timers: system startup timer, system time timer, and wakeup timer. 14e41f4b71Sopenharmony_ci 15e41f4b71Sopenharmony_ci 16e41f4b71Sopenharmony_ci## System Architecture 17e41f4b71Sopenharmony_ci 18e41f4b71Sopenharmony_ci**Figure 1** Architecture of the time and time zone subsystem 19e41f4b71Sopenharmony_ci 20e41f4b71Sopenharmony_ci 21e41f4b71Sopenharmony_ci 22e41f4b71Sopenharmony_ci 23e41f4b71Sopenharmony_ci## Directory Structure 24e41f4b71Sopenharmony_ci 25e41f4b71Sopenharmony_ciThe source code of the time and time zone subsystem is stored in the **/base/time** directory. 26e41f4b71Sopenharmony_ci 27e41f4b71Sopenharmony_ciThe directory structure is as follows: 28e41f4b71Sopenharmony_ci 29e41f4b71Sopenharmony_ci``` 30e41f4b71Sopenharmony_ci/base/time/time_service 31e41f4b71Sopenharmony_ci├── etc # Process configuration files 32e41f4b71Sopenharmony_ci├── figures # Architecture diagram 33e41f4b71Sopenharmony_ci├── framework/js/napi # JS APIs that are parsed to NAPIs 34e41f4b71Sopenharmony_ci├── interfaces/inner_api # APIs provided for external systems 35e41f4b71Sopenharmony_ci├── services # Service implementation 36e41f4b71Sopenharmony_ci│ └── profile # System service and process configuration files 37e41f4b71Sopenharmony_ci└── utils # Utilities, for example, log utility 38e41f4b71Sopenharmony_ci``` 39e41f4b71Sopenharmony_ci 40e41f4b71Sopenharmony_ci## Repositories Involved 41e41f4b71Sopenharmony_ci 42e41f4b71Sopenharmony_ci[time_service](https://gitee.com/openharmony/time_time_service) 43
