The recent announcement that GlobalFoundries will acquire MIPS Technologies highlights the curious afterlife of a once-revolutionary computer architecture. Yet this acquisition underscores a critical fact: MIPS Technologies no longer designs MIPS processors, having abandoned its namesake architecture for RISC-V in 2021. This move represents the near-final chapter for a CPU architecture that pioneered RISC principles and powered billions of devices.

From Stanford Labs to Silicon Glory
MIPS began in the early 1980s at Stanford University under John Hennessy. Its name—Microprocessor without Interlocked Pipeline Stages—reflected its innovative design approach. Alongside Berkeley RISC, MIPS was foundational in proving Reduced Instruction Set Computer concepts. Commercialized by MIPS Computer Systems, it became one of the first successful fabless semiconductor companies.

MIPS processors achieved notable success:
- Nintendo 64's Heart: The NEC VR4300 (MIPS R4300i derivative) powered the console, famously inspiring the 'MIPS' rabbit character in Super Mario 64. Despite the '64-bit' hype, memory bottlenecks limited its potential.
- PlayStation Legacy: Sony adopted MIPS R3000 for its first PlayStation, selling over 100 million units. The PS2 continued with MIPS.
- Workstation Dominance: Silicon Graphics (SGI) used high-end MIPS chips like the R4000/R16000 in iconic machines like the Tezro workstation.

"ARM took no pleasure in the demise of such a competent technical competitor. The MIPS processors had spurred ARM to develop many features... The competition had been very good for ARM." — Keith Clarke, former ARM VP, in 'Culture Won'

The Unraveling: Corporate Chaos and Strategic Errors
MIPS's decline wasn't technical but strategic:
1. Corporate Instability: After SGI sold MIPS in 1998, it passed through Imagination Technologies, Tallwood Venture Capital, and Wave Computing—which declared bankruptcy in 2020.
2. Missed Opportunities: Nintendo and Sony eventually shifted to IBM POWER and custom architectures, while Microsoft's Xbox embraced x86.
3. ARM's Contrast: ARM's consistent licensing model and stable ownership (until recent acquisitions) outmaneuvered MIPS's turmoil. ARM secured design wins in mobile that MIPS couldn't match.

Legacy Beyond Obsolescence
Though commercially sidelined, MIPS's influence persists:
- Chinese Silicon: Loongson's early processors used MIPS-derivative architectures before creating LoongArch.
- Embedded Systems: Millions of routers, satellites, and industrial devices still run on MIPS cores.
- Open-Source Support: Linux maintains MIPS architecture support, and compilers like GCC still target it.

The acquisition by GlobalFoundries focuses on MIPS's AI IP portfolio, not the historic architecture. Like its namesake rabbit in Mario 64—a testing tool discarded after development—MIPS the architecture served as a critical but transient force. Its journey underscores how corporate stewardship and ecosystem building are as vital as technical innovation in the processor landscape. RISC-V's rise, ironically championed by MIPS's own corporate successor, now carries forward the RISC ethos MIPS helped establish.