MultiFinder

MultiFinder was the name of an extension software for the Apple Macintosh, introduced in System Software in 1988 and included in System Software 6. It allowed the use of the concept of cooperative mulitarea between several applications at the same time; a breakthrough with respect to other systems, where you could only run one application at a time. With the advent of System 7, MultiFinder became an integral part of the operating system until the advent of Mac OS X.

Previous to MultiFinder, Apple developers had created the Switcher software in 1985, which had initial support in memory to run a form of multitasking and was the predecessor of MultiFinder.

MultiFinder's main function is to allow multiple software applications simultaneously, with the ability for them to reside in memory. With just one click, you could move from one application to another, and also the ability to copy information from one application to another.

wiki