Classic

Classic, or Classic Environment, is a hardware and software abstraction layer in early versions of Mac OS X that allows applications compatible with Mac OS 9 to run on the Mac OS X operating system. The name "Classic" is also sometimes used by software vendors to refer to the application programming interface available to "classic" applications, to differentiate between programming for Mac OS X and the previous version of the Mac OS. Classic is supported on PowerPC-based Macs running versions of Mac OS X up to v10.4 Tiger, but is not supported on v10.5 Leopard and later, nor on Intel-based Macs running any version of Mac OS X. Classic is a descendant of Rhapsody's "Blue Box" emulation layer, which served as a proof of concept. It uses a...