The M6100 PICA is a system logic chipset designed by Acer Laboratories

Acer Laboratories Incorporated

Acer Laboratories Incorporated is a major designer and manufacturer of integrated circuits for the personal computer and embedded systems markets. It is a subsidiary of the Acer group....

 introduced in 1993. PICA stands for Performance-enhanced Input-output and CPU Architecture. It was based on the Jazz

Jazz (computer)

The Jazz computer architecture was a motherboard and chipset design originally developed by Microsoft for use in developing Windows NT. The design was eventually used as the basis for most MIPS-based Windows NT systems....

 architecture developed by Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

 and supported the MIPS Technologies

MIPS Technologies

MIPS Technologies, Inc. , formerly MIPS Computer Systems, Inc., is most widely known for developing the MIPS architecture and a series of pioneering RISC chips. MIPS provides processor architectures and cores for digital home, networking and mobile applications.MIPS Computer Systems Inc. was...

 R4000

R4000

The R4000 is a microprocessor developed by MIPS Computer Systems that implemented the MIPS III instruction set architecture . Officially announced on 1 October 1991, it was one of the first 64-bit microprocessors and the first MIPS III implementation...

 or R4400 microprocessors. The chipset was designed for computers that run Windows NT

Windows NT

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...

, and therefore used ARC

Advanced RISC Computing

Advanced RISC Computing is a specification promulgated by a defunct consortium of computer manufacturers , setting forth a standard MIPS RISC-based computer hardware and firmware environment....

 firmware

Firmware

In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...

 to boot Windows NT. The chipset consisted of six chips: a CPU and secondary cache controller, a buffer, a I/O cache and bus controller, a memory controller

Memory controller

The memory controller is a digital circuit which manages the flow of data going to and from the main memory. It can be a separate chip or integrated into another chip, such as on the die of a microprocessor...

, and two data buffers.

PICA was used by Acer in its Formula 4000 personal workstation, which NEC sold under the OEM name RISCStation Image

NEC RISCstation

The NEC RISCstation was a line of computer workstations made by NEC in the mid-1990s, based on MIPS RISC microprocessors and designed to run Microsoft Windows NT...

.