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. Operating systems Since 1991, IBM had a long-standing desire for a unifying operating system that would simultaneously host all existing operating systems as personalities upon one microkernel. From 1991 to 1995, the company designed and aggressively evangelized what would become Workplace OS, primarily targeting PowerPC. When the first PowerPC products reached the market, they were met with enthusiasm. In addition to Apple, both IBM and the Motorola Computer Group offered systems built around the processors. Microsoft released Windows NT 3.51 for the architecture, which was used in Motorola's PowerPC servers, and Sun Microsystems offered a version of its Solaris OS. IBM ported its AIX Unix. Workplace OS featured a new port of OS/2 (with Intel emulation for application compatibility), pending a successful launch of the PowerPC 620. Throughout the mid-1990s, PowerPC processors achieved benchmark test scores that matched or exceeded those of the fastest x86 CPUs. Ultimately, demand for the new architecture on the desktop never truly materialized. Windows, OS/2, and Sun customers, faced with the lack of application software for the PowerPC, almost universally ignored the chip. IBM's Workplace OS platform (and thus, OS/2 for PowerPC) was summarily canceled upon its first developers' release in December 1995 due to the simultaneous buggy launch of the PowerPC 620. The PowerPC versions of Solaris and Windows were discontinued after only a brief period on the market. Only on the Macintosh, due to Apple's persistence, did the PowerPC gain traction. To Apple, the performance of the PowerPC was a bright spot in the face of increased competition from Windows 95 and Windows NT-based PCs. With the cancellation of Workplace OS, the general PowerPC platform (especially AIM's Common Hardware Reference Platform) was instead seen as a hardware-only compromise to run many operating systems one at a time upon a single unifying vendor-neutral hardware platform. In parallel with the alliance between IBM and Motorola, both companies had development efforts underway internally. The PowerQUICC line was the result of this work inside Motorola. The 4xx series of embedded processors was