├── apps # User-space init and shell application programs
├── arch # System architecture, such as ARM
│ └── arm # Code for ARM architecture
├── bsd # Code of the driver and adaptation layer module related to the FreeBSD, such as the USB module
├── compat # Kernel API compatibility
│ └── posix # POSIX APIs
├── drivers # Kernel drivers
│ └── char # Character device
│ ├── mem # Driver for accessing physical input/output (I/O) devices
│ ├── quickstart # APIs for quick start of the system
│ ├── random # Driver for random number generators
│ └── video # Framework of the framebuffer driver
├── fs # File system module, which mainly derives from the NuttX open-source project
│ ├── fat # FAT file system
│ ├── jffs2 # JFFS2 file system
│ ├── include # Header files exposed externally
│ ├── nfs # NFS file system
│ ├── proc # proc file system
│ ├── ramfs # RAMFS file system
│ └── vfs # VFS layer
├── kernel # Kernel modules including the process, memory, and IPC modules
│ ├── base # Basic kernel modules including the scheduling and memory modules
│ ├── common # Common components used by the kernel
│ ├── extended # Extended kernel modules including the dynamic loading, vDSO, and LiteIPC modules
│ ├── include # Header files exposed externally
│ └── user # Init process loading
├── lib # Kernel library
├── net # Network module, which mainly derives from the lwIP open-source project
├── platform # Code for supporting different systems on a chip (SOCs), such as Hi3516D V300
│ ├── hw # Logic code related to clocks and interrupts
│ ├── include # Header files exposed externally
│ └── uart # Logic code related to the serial port
├── platform # Code for supporting different systems on a chip (SOCs), such as Hi3516D V300
├── security # Code related to security features, including process permission management and virtual ID mapping management
├── syscall # System calling
└── tools # Building tools as well as related configuration and code
```
## Constraints<a name="section119744591305"></a>
- Programming languages: C and C++
- Applicable development boards: Hi3516D V300
- Hi3516D V300 uses the FAT file system by default.
## Usage<a name="section741617511812"></a>
OpenHarmony LiteOS Cortex-A supports the [Hi3516D V300](https://gitee.com/openharmony/docs/blob/master/en/device-dev/quick-start/quickstart-lite-introduction-hi3516.md). You can develop and run your applications based on this development board.
You need to set up the compilation environment on Linux.
-[Setting Up Ubuntu Development Environment](https://gitee.com/openharmony/docs/blob/master/en/device-dev/quick-start/quickstart-lite-env-setup.md)
- For Hi3516D V300, see [Setting Up the Hi3516 Development Environment](https://gitee.com/openharmony/docs/blob/master/en/device-dev/quick-start/quickstart-lite-steps-hi3516-setting.md).
Download and decompress a set of source code on a Linux server to acquire the [source code](https://gitee.com/openharmony/docs/blob/master/en/device-dev/get-code/sourcecode-acquire.md).
### Compilation and Building<a name="section2081013992812"></a>
For details about how to develop the first application, see:
-[Developing the First Example Program Running on Hi3516](https://gitee.com/openharmony/docs/blob/master/en/device-dev/quick-start/quickstart-lite-steps-hi3516-running.md)
