The early Macs were very limited (small black and white screen, 128k of RAM, less software than was available on a PC, and everything about it was more expensive). They were, however, totally cool. Over the next decade, three things would happen: Microsoft Windows would adopt nearly every feature native to the Mac, and the Macintosh system would expand out of its "sealed box" original design and become a modular, expandable system just like a PC.

The third thing was the rise of computer viruses. 

In the early '90's, there were plenty of native Macintosh viruses. Macintosh system 6 and 7, especially, were subject to a number of Mac native vulnerabilities, including one known as the "resource fork virus." This sort of virus could be appended to any executable on the system, taking advantage of the Mac system file storage and recall system. There were dozens of such viruses and other malware that was specific to applications (including Microsoft applications for the Mac). There were Mac antivirus packages made by most of the leading security vendors of the day and several smaller vendors as well. By about 1994, almost every Macintosh user had AV software installed. A fierce core of Mac 'true believers' has always held to an almost religious fervor about this computer system, in all of its various guises.

In the 21st century, Macs have run on an operating system based on a Unix kernel, called "OS X" (be careful to refer to this as "OS 10," as the X is a roman numeral for that). System version 9, which preceded it, was the last version of the old Mac OS, and the story about that particular change is too long and complicated for this article.

This, for most modern users, is where the Mac begins.

By this time, Windows-based systems and Apple systems have roughly the same capabilities in every way. Apple stuck to innovative design and remains much more expensive than a standard Windows-based computer, in everything from initial system cost to software costs, even to the cost of interface cables. One of the main differentiators between the two systems appeared to be the apparent immunity of the Mac, as computer malware rose to the staggering problems we experience today. From the rise of cybercrime to the ubiquity of botnets and malware, this appeared to be a genuine advantage to the already fiercely loyal users of the Macintosh computer. Since most Mac users today have never used the older operating system, many of them no longer used antimalware scanners.