Yun OS (simplified Chinese: 云OS; traditional Chinese: 雲OS; literally: "Cloud OS"), also called Aliyun OS (simplified Chinese: 阿里云; traditional Chinese: 阿里雲; pinyin: ālǐyún) is a Linux distribution designed for smartphones based on the Android Open Source Project. It is developed by AliCloud, a subsidiary of Chinese company Alibaba Group. Aliyun was released in China on July 28, 2011.