The Macintosh operating system has come a long way since first being introduced on January 24, 1984.
Mac System 1.0
The very first version of the Macintosh system software, System 1.0, was released on January 24, 1984, with a size of just 216K and is the operating system that accompanied the Macintosh 128K.
It was made up of the desktop, windows, icons, folders, the menu bar, documents, applications, the trash (aka wastebasket), and system software. It could run only one application at a time and was black and white.
Most of the icons and fonts were designed by Susan Kare.
Just four months after the release of the first Macintosh, Apple released an update to the OS with the introduction of System 1.1.
The biggest change that came along with the introduction of System 1.1 was the increase in speed in disk copying. Apple upped the Finder's memory buffer, giving Finder the ability to copy large segments all at once. Steve Jobs was famously focused on system startup speed and wanted the system to boot as fast as possible.
System 3.0 was one of the most notable upgrades debuted with the introduction of the Mac Plus, and like the Plus, it forever changed the way Mac advocates used their machines. This was the most notable upgrade, second only to System 7 and Mac OS 8 to come in later years.
Thanks to a new disk cache, which stored commonly used computing instructions in the memory, Finder -- now at version 5.1 -- was much faster.
Released on January 19, 1998, Mac OS 8.1 was the last version to run on Macintosh computers with a Motorola 68000-family processor.
The 8.1 OS integrated support for the HFS Plus file system format, which supported both larger file sizes and longer file names and used a smaller block size, which utilized the available space on larger drives more efficiently.