Mac vs PC
Mac and PC are computer platforms that used to be distinguished by design architecture and chipsets. Today, there are almost no differences except for the fact that Macs are manufactured by Apple and PCs are not (although technically speaking, Macs are PCs). Another distinguishing point is that Macs come bundled with the Apple Mac OS X operating system. Visit Apple Mac OS X vs Microsoft Windows for a comparison between operating systems.
Mac refers to the Macintosh computers produced by Apple. More recently, the term is used to point to iMac, Mac Pro, Mac mini and Macbook computers.
PC is technically a more general term, of which the original definition was Personal Computer. The term evolved to become a polar term, in contrast to Mac computers, usually meaning a computer running on an x86 architecture. Through out the 1980s and '90s the term "IBM compatible PC" was used, as the standard by which all PCs follow are based off an IBM design, so today's use of "PC" is simply an abbreviated form.
Generally when most refer to "Macs & PCs" they are referring to an Apple computer running Mac OS X and a PC running Microsoft Windows; however, this is technically misleading as you can run pretty much any operating system on either. For example you can run Windows on a mac, and you can run an unauthorized, hacked version of OS X on a PC. Also many users elect to use other OSes, like Linux or BSD on either machine type as well. Macs are also technically still not fully IBM compatible PCs as they may run on an x86 architecture and many of the same components, but they have very different firmware (EFI instead of BIOS), which is part of the PC standard.
In the context of Mac vs PC, specifically, the term PC refers to the Windows Operating System created by Microsoft and the hardware it is limited to run on. Although Linux (and a number of less popular operating systems) can be compiled to run on various hardware, Mac vs PC is generally accepted to be a comparison between Mac computers and Windows computers.
Almost all the advantages claimed for Macs (no viruses, reliability) are also true for PCs running Unix (Linux, BSD, AIX etc), and so is the disadvantage of a more limited range of hardware.
This page compares the two different types of machines and hardware platforms. To see a more detailed breakdown of the differences between the two line of operating systems, visit Apple Mac OS X vs Microsoft Windows.
PCs and MAC run on the same instruction set and hobbyists have been able to install a limited version of OS X on standard PC hardware. These is a significant difference between Macintosh and PC hardware in hardware and operating system integration. Because Apple provides both the hardware and software, the installation of driver software is typically not required on Macintosh computers. This simplifies the installation of software and the addition of hardware, but can limit the range of components and peripherals available.
 Operating System
The PC's most popular operating system for end users is Windows. The most recent version is Windows 8, replacing Windows 7, which was preceded by Windows Vista, Windows XP, and several earlier versions. The Mac's most popular operating system is OS X (officially pronounced "oh ess ten", though some people say "oh ess ex"). The latest version is 10. 8 (code-named "Mountain Lion"), which followed 10.7 (code-named "Lion").
Overall, all computer manufacturers purchase their basic components from the same suppliers. Where the brands differ is in their configuration, reliability, and support. In this regard, Apple has set a high standard for quality, consistently ranking as a Consumer Reports Best Buy. Between 2008 and 2011, Consumer Reports also ranked Apple computer as having the highest reliability among all popular computer brands, including Compaq, Dell, Acer, HP, and Gateway.
Macs have limited official hardware support. While external accessories (ie. mice, keyboards) and display hardware (ie. monitors, projectors) have wide support, Macs can only accept a limited range of internal hardware. The Mac OSX normally cannot be installed on an computer other than those created by Apple. The advantage is that Mac computers tend to have a sleeker design because they do not need to have universal support for exchangeable components.
PCs on the other hand, are manufactured by different companies using different hardware. This has the advantage that any computer part can be replaced with cheap parts. Windows can be installed on most desktop and laptop computers.
A project called Hackintosh, or OSx86, provides support for running the Mac OSX operating system on PC hardware. Although Hackintoshes are not officially supported by Apple, there have been reports of stable Hackintosh systems on both desktops and laptops, but the mac partition must be formated to the HFS+ file system and not NTFS. OSX is also able to run on computers running AMD processors.
Apple tend to cost more than similar PC models. A variety of reasons may drive this including perceived quality, level of support provided, brand loyalty, device design, bundled options, ease of use, and projected cost of ownership.
Technology commentator Leo Laporte attributes at least part of the price differences between Apple and PC computers to market forces. He argues that competition between PC makers has made them more competitively priced; however, he also notes that narrowing profit margins has forced PC makers to trim technical support services.
Although PCs still have an overwhelming popularity, Mac computers are on the rise, especially in university settings. Macs have traditionally been held in high esteem among media professionals.
Mac OS X reached a 7.3% market share among Operating Systems in December, 2007.