The Western Regions or Xiyu (Chinese: 西域; pinyin: Xīyù; Wade–Giles: Hsiyü) was a historical name specified in the Chinese chronicles between the 3rd century BC to 8th century AD that referred to the regions west of Jade Gate, most often Central Asia or sometimes more specifically the easternmost portion of it (e.g. the Tarim Basin in southern Xinjiang).

Because of its strategic location astride the Silk Road, the Western Regions have been historically significant since at least the 3rd century BC. It was the scene of conflict between the Han Dynasty and the Xiongnu until 89 AD. In the 6th century the Tang Dynasty took control over this area until the An Lushan Rebellion.

The region became significant in later centuries as a cultural conductor between East Asia, the Indian subcontinent, the Islamic world and Europe, such as during the period of the Mongol Empire. One of the most significant exports of the Western Regions was Buddhism, which was carried by traders and pilgrim monks to China. The Tang Dynasty monk Xuanzang's journey crossed the region on his way to study in India, resulted in the classic text Great Tang Records of the Western Regions upon his return to the Tang capital Chang'an.

MS-DOS ( /ˌɛmɛsˈdɒs/ EM-es-DOSS; short for Microsoft Disk Operating System) is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating systems offering a graphical user interface (GUI), in particular by various generations of the Microsoft Windows operating system.

MS-DOS grew from a 1981 request by IBM for an operating system for its IBM PC range of personal computers. Microsoft quickly bought the rights to QDOS (Quick and Dirty Operating System), also known as 86-DOS, from Seattle Computer Products, and began work on modifying it to meet IBM's specification. The first edition, MS-DOS 1.0, was launched in 1982. The version shipped with IBM's PCs was called PC DOS. Although MS-DOS and PC DOS were initially developed in parallel by Microsoft and IBM, the two products eventually went their separate ways.