macOS (formerly known as Mac OS X, pronounced Mac OS "Ten" and later OS X) is an operating system like Windows and Linux desingned for Mac computers that was released in January 24, 1984 by Apple, although more expensive than the regular Microsoft Windows. Today, Apple's Mac is still more expensive than Microsoft Windows.
The "Classic" Mac OS ran from System 1 to Mac OS 9.xx. However, the OS began to struggle with stability as it lacked memory protection (all memory was shared and any program can access any memory, including each others' and the system memory, causing corruption and stability issues) and pre-emptive multitasking. Efforts to include these key technologies into Mac OS failed in the now-infamous Copland project. Eventually, Apple bought NeXTSTEP, bringing Steve Jobs under the helm of Apple. Apple later worked on a completely new version of Mac, titled Mac OS X based on NeXTSTEP.
The current version is macOS Mojave 10.145.
The Macintosh OS originated on the first Apple Computer, the Apple Macintosh. It performs the same functions as Windows but doesn't have a library of software as vast as Windows and is therefore best suited for business and school use. It doesn't have many games for its platform but is desired for certain programs like GarageBand, a music editing software, and iMovies, a movie maker. The Macintosh OS was named after Steve Jobs' favorite type of Apple, the McIntosh Apple.
After Apple's transition from PowerPC to Intel processors, Apple included a utility called BootCamp, which allowed users to install Windows in a dualboot configuration.
Only a few pieces of malware are targeted towards Macs, due to the lower market share, and the fact that it is harder to write programs for.