Classic Mac OS

>> Mac OS Classic <<
| Mac System Software 1 | Mac System Software 2 | Mac System Software 3 | Mac System Software 4 | Mac System Software 5 |
| Mac System Software 6 | Mac OS 7 | Mac OS 8 | Mac OS 9 |

Mac OS X
| Mac OS X 10.1 Puma | Mac OS X 10.2 Jaguar | Mac OS X 10.3 Panther | Mac OS X 10.4 Tiger | Mac OS X 10.5 Leopard |
| Mac OS X 10.6 Snow Leopard |

Related:
| Motarola 68000 CPU | Motarola PowerPC CPU |

Mac OS Classic versions supported 68000 cpus until version 8.1. Subsequent versions did not.
Mac System 7.1.2 added support for PowerPC CPUs. PowerPC support was officially dropped after OS X 10.5 but it is noted that the OS X kernel is non-proprietary allowing anyone to compile a kernel for PowerPC if needed.
Mac OS X was able to run on intel CPUs since its conception but only through custom compiling of the kernel. But this did not become officially supported until Mac OS X 10.4

It cannot be assumed that early Macintosh games or all 68k games use OS Classic. This is because, Like for IBM-PC, there are bootloader games for Macintosh.

It should be noted that 'OS Classic' is an unofficial nickname for Mac OS versions 9 and earlier. Apple created an official emulator called "OS Classic" for Mac OS X that allowed applications for its older operating systems to run on it's newer systems. This has lead to minor confusion in some circles. Just remember that on UVL, the phrase means Mac OS 9 or earlier and is not meant to refer to the emulator of the same name.