The PowerPC architecture supports both 64-bit and 32-bit addressing. Early implementations used the 32-bit subset and supported only 32-bit applications. Since 1995, 64-bit processors have implemented the complete architecture allowing full binary application compatibility with existing 32-bit applications and support for new 64-bit applications. The first 64-bit CPUs were used in the AS/400 (now iSeries) platform. Today, 64-bit PowerPC chips can be found in both iSeries and pSeries systems from IBM as well as G5 hardware from Apple.
This site is dedicated to the ppc64 architecture port for the Linux kernel which runs on both iSeries and pSeries boxes with 64-bit PowerPC processors.
The ppc64 maintainer is Paul Mackerras (email@example.com).