Please discuss briefly: What are the fundamental differences between Windows, Mac OS, UNIX, and Linux operating systems for personal computers? What unique characteristics do mainframe operating systems have?
Windows is a general purpose OS, targeted largely at businesses and running at IBM compatible PCs. It has a very wide range of applications, many of which can be downloaded and run for free. It is notorious for the number of security holes it has.
Mac OS is the operating system for Apple computers. It has a highly polished user interface, takes very little effort to use. Mac OS isn't as popular as Windows, so you won't find the breadth of applications available for it. Also, if you want to do something cool, special and different, then you're stuck because the OS is designed around people who don't want to customize. Mac OS really only runs on Apple computers, and the whole package tends to be more expensive than the Windows equivalent for the same power, although proponents argue that the maintenance effort in Windows makes up for it.
Mac OS is based on Berkeley ...
In about 570 words, this solution briefly compares and contrasts different computer operating systems: Windows, Mac OS, Unix and Linux. This response is very easy to understand, even for individuals who are not very familiar with computer language.