Wine is a free and open-source compatibility layer that aims to allow software developed for Microsoft Windows to run on Unix-like operating systems. Wine also provides a software library, known as Winelib, against which developers can compile Windows applications to help port them to Unix-like systems.

Mac OS 9 is the ninth and last major release of Apple's classic Mac OS operating system. Introduced on October 23, 1999, it was promoted by Apple as 'The Best Internet Operating System Ever', highlighting Sherlock 2's Internet search capabilities, integration with Apple's free online services known as iTools and improved Open Transport networking. While Mac OS 9 lacks protected memory and full pre-emptive multitasking, lasting improvements include the introduction of an automated Software Update engine and support for multiple users.

The Mac 68k emulator is a software emulator built into all versions of the classic Mac OS for PowerPC. This emulator enabled running applications and system code that were originally written for the 680x0-based Macintosh models. With a few exceptions, notably Connectix's RAM Doubler, the emulator ran all software with no noticeable impact other than lower performance relative to the same program when compiled for PowerPC.

Star Trek is the code name that was given to a secret prototype project, running a port of Mac OS 7 and its applications on Intel-compatible x86 personal computers. The project, starting in February 1992, was conceived in collaboration between Apple Computer, who provided the majority of engineers, and Novell, who at the time was one of the leaders of cross-platform file-servers. The plan was that Novell would market the resulting OS as a challenge to Microsoft Windows, but the project was discontinued in 1993 and never released, although components were reused in other projects. The project was named after the Star Trek science fiction franchise with the slogan 'To boldly go where no Mac has gone before'.

PearPC is an architecture-independent PowerPC platform emulator capable of running many PowerPC operating systems, including pre-Intel versions of Mac OS X, Darwin and Linux. It is released under the terms of the GNU General Public License (GPL). It can be executed on Microsoft Windows, Linux, FreeBSD and other systems based on POSIX-X11. The first official release was made on May 10, 2004.

Darwine was a port of the Wine libraries to Darwin and Mac OS X. The Darwine project intended to port and develop Wine as well as other supporting tools that would allow Darwin and Mac OS X users to run Windows applications and to provide a Win32 API compatibility at application source code level.

ResEdit is a discontinued developer tool application for the Apple Macintosh, used to create and edit resources directly in the Mac's resource fork architecture. It is an alternative to tools such as REdit, and the resource compiler Rez. For the average user, ResEdit is generally easier to use, because it uses a graphical user interface. Although it had been intended to be a developer tool, power users often use it to edit icons, menus, and other elements of an application's GUI, customizing it to their own preferences.

vMac was an open source emulator for Mac OS on Windows, DOS, OS/2, NeXTSTEP, Linux-Unix, and other platforms. Although vMac has been abandoned, Mini vMac, an improved spinoff of vMac, is currently developed. vMac and Mini vMac emulate a Macintosh Plus and can run Apple Macintosh System versions 1.1 to 7.5.5. vMac and Mini vMac support CPU emulation from Motorola 68000 to 68040, display output, sound, floppy disk insert, HFV image files, and more. Some vMac ports include extra features such as CD-ROM support, basic serial port (SCC) support, Gemulator ROM board support, and various performance improvements. Although the website is still in operation, most vMac development slowed to a halt in 1999, and no official releases have been made since. Many of the developer e-mail addresses listed on the website are not currently working.

Basilisk II is an emulator which emulates Apple Macintosh computers based on the Motorola 68000 series. The software is cross-platform and can be used on a variety of operating systems.

A Macintosh clone is a computer running the Mac OS operating system that was not produced by Apple Inc. The earliest Mac clones were based on emulators and reverse-engineered Macintosh ROMs. During Apple's short lived Mac OS 7 licensing program authorized Mac clone makers were able to either purchase 100% compatible motherboards or build their own hardware using licensed Mac reference designs.

The Mac transition to Intel processors was the process of changing the central processing unit (CPU) of Apple Inc.'s line of Mac computers, as well as its server offerings at the time, from PowerPC to Intel x86 processors.

A Hackintosh is a computer that runs an Apple Macintosh operating system on computer hardware not authorized for the purpose by Apple. 'Hackintoshing' began as a result of Apple's 2005 transition to Intel Processors, away from PowerPC. Since 2005, Mac computers use the same x86-64 computer architecture as many other desktop PCs, laptops, notebooks and servers, meaning that in principle, the code making up macOS/OS X systems and software can be run on alternative platforms with minimal compatibility issues. Benefits cited for 'Hackintoshing' can include cost, ease of repair and piecemeal upgrade, and freedom to use customized choices of components that are not available in the branded Apple products. macOS can also be run on several non-Apple virtualization platforms, although such systems are not usually described as Hackintoshes. Hackintosh laptops are sometimes referred to as 'Hackbooks'.

The Apple–Intel architecture, or Mactel, is an unofficial name used for Apple Macintosh personal computers developed and manufactured by Apple Inc. that use Intel x86 processors, rather than the PowerPC and Motorola 68000 ('68k') series processors used in their predecessors. With the change in architecture, a change in firmware became necessary; Apple selected the Intel-designed Extensible Firmware Interface (EFI) as its comparable component to the Open Firmware used on its PowerPC architectures, and as the firmware-based replacement for the PC BIOS from Intel. With the change in processor architecture to x86, Macs gained the ability to boot into x86-native operating systems, while Intel VT-x brought near-native virtualization with Mac OS X as the host OS.

The Amiga computer can be used to emulate several other computer platforms, including legacy platforms such as the Commodore 64, and its contemporary rivals such as the IBM PC and the Macintosh.

Q is a free emulator software that runs on Mac OS X, including OS X on PowerPC. Q is Mike Kronenberg's port of the open source and generic processor emulator QEMU. Q uses Cocoa and other Apple technologies, such as Core Image and Core Audio, to achieve its emulation. Q can be used to run Windows, or any other operating system based on the x86 architecture, on the Macintosh.

Mac gaming refers to the use of video games on Macintosh personal computers. In the 1990s, Apple computers did not attract the same level of video game development as Microsoft Windows computers due to the high popularity of Microsoft Windows and, for 3D gaming, Microsoft's DirectX technology. In recent years, the introduction of Mac OS X and support for Intel processors has eased porting of many games, including 3D games through use of OpenGL and more recently Apple's own Metal API. Virtualization technology and Boot Camp also permit the use of Windows and its games on Macintosh computers. Today, a growing number of popular games run natively on macOS, though as of early 2019, a majority still require the use of Microsoft Windows.

The family of Macintosh operating systems developed by Apple Inc. includes the graphical user interface-based operating systems it has designed for use with its Macintosh series of personal computers since 1984, as well as the related system software it once created for compatible third-party systems.

Classic Mac OS refers to the series of operating systems developed for the Macintosh family of personal computers by Apple Inc. from 1984 to 2001, starting with System 1 and ending with Mac OS 9. The Macintosh operating system is credited with having popularized the graphical user interface concept. It was included with every Macintosh that was sold during the era in which it was developed, and many updates to the system software were done in conjunction with the introduction of new Macintosh systems.