Started with J2ME, then BlackBerry, moved on to iOS, followed by Android and now working with AngularJS on a single page web app (buzzword HTML5).
DBMSs I know (as in I used them at least once): SQLite, PostgreSQL, MySQL, Microsoft SQL Server.
OS preference: Linux Mint, OS X, Windows
Q&A for professional and enthusiast programmers
Q&A for power users of Apple hardware and software
Q&A for meta-discussion of the Stack Exchange family of Q&A websites