emulator
Mac On a Stick - Portable Macintosh on a USB stick
Mac On a Stick aka: Mini vMac, just as the name imposes, is a portable Macintosh emulated operating system that can be booted and run from a USB flash drive. Although for most, it isn't a complete replacement operating system, a MOS installation can include many useful applications running from an emulated Mini vMac (a Macintosh Plus emulator).