# Overview - [System Types](#section767218232110) - [Document Outline](#section19810171681218) This topic provides a panorama of all documents for you to obtain helpful information quickly. These documents are classified based on your learning progress and development scenarios of OpenHarmony. ## System Types It is good practice to understand the system types for you to find useful documents that can guide your development. OpenHarmony is an open-source distributed operating system for all scenarios. It uses a component-based design to tailor its features to better suit devices with 128 KiB to GiB-level of RAM. You can integrate a flexible combination of system components based on the hardware capabilities of the device. To make the integration simple and easy on different hardware, OpenHarmony defines three basic system types. You only need to select a suitable system type and configure the mandatory component set, thereby developing a system for your device at the minimum workload. The definitions of the basic system types are provided as follows for your reference: - Mini system A mini system runs on the devices whose memory is greater than or equal to 128 KiB and that are equipped with MCU processors such as Arm Cortex-M and 32-bit RISC-V. This system provides multiple lightweight network protocols and graphics frameworks, and a wide range of read/write components for the IoT bus. Typical products include connection modules, sensors, and wearables for smart home. - Small system A small system runs on the devices whose memory is greater than or equal to 1 MiB and that are equipped with application processors such as Arm Cortex-A. This system provides higher security capabilities, standard graphics frameworks, and video encoding and decoding capabilities. Typical products include smart home IP cameras, electronic cat eyes, and routers, and event data recorders \(EDRs\) for smart travel. - Standard system A standard system runs on the devices whose memory is greater than or equal to 128 MiB and that are equipped with application processors such as Arm Cortex-A. This system provides a complete application framework supporting the enhanced interaction, 3D GPU, hardware composer, diverse components, and rich animations. This system applies to high-end refrigerator displays. In addition, OpenHarmony provides a series of optional system components that can be configured as required to support feature extension and customization. These system components are combined to form a series of system capabilities that, for better understanding, are described as features or functions for you to choose. ## Document Outline - [Mini and Small System Development Guidelines](#table3762949121211) - [Standard System Development Guidelines](#table17667535516) **Table 1** Mini and small system development guidelines \(reference memory < 128 MB\)

Topic	Development Scenario	Documents
About OpenHarmony	Getting familiar with OpenHarmony	About OpenHarmony Glossary
Development resources	Preparing for your development	Obtaining Source Code Tool Acquisition
Quick start	Getting started with setup, build, burning, debugging, and running of OpenHarmony	Mini and Small Systems
Basic capabilities	Using basic capabilities of OpenHarmony	Kernel for Mini Systems Kernel for Small Systems Drivers Subsystems Security Guidelines Privacy Protection
Advanced development	Developing smart devices based on system capabilities	WLAN-connected Products Cameras Without a Screen Cameras with a Screen
Porting and adaptation	Porting and adapting the OpenHarmony to an SoC Porting and adapting the OpenHarmony to a third-party library	Mini System SoC Porting Guide Small System SoC Porting Guide Third-Party Library Porting Guide for Mini and Small Systems
Contributing components	Contributing components to OpenHarmony	HPM Bundle Development Specifications HPM Bundle Development Guidelines HPM Bundle Development Example
Reference	Referring to development specifications	API References FAQs

**Table 2** Standard system development guidelines \(reference memory ≥ 128 MB\)

Topic	Development Scenario	Documents
About OpenHarmony	Getting familiar with OpenHarmony	About OpenHarmony Glossary
Development resources	Preparing for your development	Obtaining Source Code Tool Acquisition
Quick start	Getting started with setup, build, burning, debugging, and running of OpenHarmony	Standard System
Basic capabilities	Using basic capabilities of OpenHarmony	Kernel for Standard Systems Drivers Subsystems Security Guidelines Privacy Protection
Advanced development	Developing smart devices based on system capabilities	Development Guidelines on Clock Apps Development Example for Platform Drivers Development Example for Peripheral Drivers
Porting and adaptation	Porting and adapting the OpenHarmony to a third-party library	Standard System Porting Guide A Method for Rapidly Porting the OpenHarmony Linux Kernel
Contributing components	Contributing components to OpenHarmony	HPM Bundle Development Specifications HPM Bundle Development Guidelines HPM Bundle Development Example
Reference	Referring to development specifications	API References FAQs