Microsoft Word is a word processor developed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS (1983), the Apple Macintosh (1985), the AT&T Unix PC (1985), Atari ST (1988), SCO UNIX (1994), OS/2 (1992), and Windows (1989). Commercial versions of Word are licensed as a standalone product or as a component of Microsoft Office, Windows RT or the discontinued Microsoft Works Suite. Freeware editions of Word are Microsoft Word Viewer and Word Web App on SkyDrive, both of which have limited feature sets.