Editing PowerPC (section)

=== Apple and Motorola involvement ===
Apple had already realized the limitations and risks of its dependency upon a single CPU vendor at a time when Motorola was falling behind on delivering the [[Motorola 68040|68040]] CPU. Furthermore, Apple had conducted its own research and made an experimental quad-core CPU design called Aquarius,<ref name="Apple: The Inside Story"/>{{rp|86–90}} which convinced the company's technology leadership that the future of computing was in the RISC methodology.<ref name="Apple: The Inside Story"/>{{rp|287–288}} IBM approached Apple with the goal of collaborating on the development of a family of single-chip microprocessors based on the POWER architecture. Soon after, Apple, being one of Motorola's largest customers of desktop-class microprocessors,<ref>{{cite web | title = Tech Files Columns, 1987–1990 | url = http://www.joelwest.org/Press/TechFiles.html#01.03.89 | url-status = live | archive-url = https://web.archive.org/web/20130606044423/http://www.joelwest.org/Press/TechFiles.html#01.03.89 | archive-date = June 6, 2013 | df = mdy-all }}</ref> asked Motorola to join the discussions due to their long relationship, Motorola having had more extensive experience with manufacturing high-volume microprocessors than IBM, and to form a second source for the microprocessors. This three-way collaboration between Apple, IBM, and Motorola became known as the [[AIM alliance]].

In 1991, the PowerPC was just one facet of a larger alliance among these three companies. At the time, most of the personal computer industry was shipping systems based on the Intel 80386 and 80486 chips, which have a [[complex instruction set computer]] (CISC) architecture, and development of the [[P5 (microarchitecture)|Pentium]] processor was well underway. The PowerPC chip was one of several joint ventures involving the three alliance members, in their efforts to counter the growing Microsoft-Intel dominance of personal computing.

For Motorola, POWER looked like an unbelievable deal. It allowed the company to sell a widely tested and powerful RISC CPU for little design cash on its own part. It also maintained ties with an important customer, Apple, and seemed to offer the possibility of adding IBM too, which might buy smaller versions from Motorola instead of making its own.

At this point Motorola already had its own RISC design in the form of the [[Motorola 88000|88000]], which was doing poorly in the market. Motorola was doing well with its [[Motorola 68000|68000]] family and the majority of the funding was focused on this. The 88000 effort was somewhat starved for resources.

The 88000 was already in production, however; [[Data General]] was shipping 88000 machines and Apple already had 88000 prototype machines running. The 88000 had also achieved a number of embedded design wins in telecom applications. If the new POWER one-chip version could be made bus-compatible at a hardware level with the 88000, that would allow both Apple and Motorola to bring machines to market far faster since they would not have to redesign their board architecture.

The result of these various requirements is the PowerPC (''performance computing'') specification. The differences between the earlier POWER instruction set and that of PowerPC is outlined in Appendix E of the manual for PowerPC ISA v.2.02.<ref name=powerpc_archguide />