Adobe has released security updates for Adobe Acrobat and Reader for Windows and Macintosh. It was released for Microsoft Windows, Macintosh, and PlayStation. VMware Fusion is a software hypervisor developed by VMware for Macintosh computers. Support for some early G3 computers such as the Power Macintosh and PowerBook was discontinued. They were released as shareware titles for Macintosh and Windows systems. System software contains support for an unreleased Macintosh 256K. Photoshop was initially only available on Macintosh. In May 1989, Symantec launched Symantec Antivirus for the Macintosh (SAM). This software is available only for certain versions of the Macintosh or Windows operating systems. Shockwave originated with the VideoWorks application developed by MacroMind for the original Apple Macintosh. Apple selected the 68HC000 for use in the Macintosh Portable. Later, Apple made a numeric keypad available for the Macintosh 128K. Apple has developed a series of Macintosh operating systems. Apple began bundling both with every Macintosh. Snow Leopard is available as an upgrade for Intel-based Macintosh computers.