The IBM RT PC (RISC Technology Personal Computer) is a family of workstation computers from IBM introduced in 1986. These were the first commercial computers from IBM that were based on a reduced instruction set computer (RISC) architecture. The RT PC uses IBM's proprietary ROMP microprocessor, which commercialized technologies pioneered by IBM Research's 801 experimental minicomputer (the 801 was the first RISC). The RT PC runs three operating systems: AIX, the Academic Operating System (AOS), and Pick. The RT PC's specifications were regarded as "less than impressive" compared to contemporary workstations by its competitors in that particular market, although the product was deemed deserving of "a healthy amount of respect", particularly with the prospect of IBM as "a serious competitor" who, despite having a product whose performance was an estimated 18 months behind other vendors, would potentially be able to catch up quickly by applying the company's renowned technological capabilities. Given such performance limitations, the RT PC had little commercial success as a result. IBM responded by introducing the RS/6000 workstations in 1990, which used a new IBM-proprietary RISC processor, the POWER1. All RT PC models were discontinued by May 1991. Hardware Two basic types were produced: a floor-standing desk-side tower, and a table-top desktop. Both types featured a special board slot for the processor card, as well as machine-specific RAM cards. Each machine had one processor slot, one co-processor slot, and two RAM slots. There were three versions of the processor card: The Standard Processor Card or 032 card had a 5.88MHz clock rate (170ns cycle time), 1MB of standard memory (expandable via 1, 2, or 4MB memory boards). It could be accompanied by an optional Floating-Point Accelerator (FPA) board, which contained a 10MHz National Semiconductor NS32081 floating point coprocessor. This processor card was used in the original RT PC models (010, 020, 025, and A25) announced on January 21, 1986. The Advanced Processor Card had a 10MHz clock (100ns) and either 4MB memory on the processor card, or external 4MB ECC memory cards, and featured a built-in 20MHz Motorola 68881 floating-point processor. The Advanced Processor Card could be accompanied by an optional Advanced Floating-Point Accelerator (AFPA) board, which was based around the Analog Devices ADSP-3220 FP multiplier and ADSP-3221 FP ALU. Models 115, 125, and B25 used these cards. These models were announced on February 17, 1987. The Enhanced Advanced Processor Card sported a 12.5MHz clock (80ns), 16MB