XPostFacto

XPostFacto is an open source utility that enables the installation of PowerPC versions of Mac OS X up to Mac OS X v10.4 (Tiger), and Darwin on some PowerPC-based Apple Macintosh systems that are not officially supported for them by Apple.

XPostFacto - often referred to as "XPF" - runs under Mac OS 9 and allows an unmodified Mac OS X installation disc to be launched on machines which cannot boot Mac OS X unaided. This allows Mac OS X to be installed on certain Mac models which could otherwise only run System 7, Mac OS 8 or Mac OS 9, albeit sometimes with incomplete functionality. For example, it can be used to install Mac OS X v10.2 on a PowerPC 604 equipped Power Macintosh 8600 or 9600.

It also allows more recent versions of Mac OS X to be installed on older G3 Macs which can only officially run earlier versions of OS X - for example, it allows Mac OS X v10.3 and Mac OS X v10.4 to run successfully on Beige G3s, 10.2 having been the last version supported by Apple. It can even facilitate otherwise-awkward installations on supported machines; for instance, it allows Mac OS X v10.4, which shipped on DVD media, to be installed onto a Blue and White G3 with only an external, non-bootable DVD drive. Likewise, Mac OS X 10.4 Tiger ended support for machines that lacked built-in FireWire ports, these being the original iMac G3s and iBook G3s, but XPostFacto allows the use of 10.4 on them.

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