An instruction set architecture (ISA) is crucial to the development of processors and their software ecosystems. In the last half century, the majority of ISAs have been owned by single companies, whether product companies for their own chips/systems or processor IP companies who licensed their processors to chip developers. Does ISA ownership matter? Let’s consider three proprietary ISAs and their history.
Firstly, the Alpha ISA was developed by Digital Equipment Corporation (DEC) for its workstations and servers and was released in 1992. In the mid-1990s, this was considered a worthy competitor to SPARC and MIPS RISC architectures. However, the ownership of the ISA transferred to Compaq when DEC was acquired in 1998. Compaq in turn sold the rights to the Alpha ISA to Intel in 2001, and in the same year Compaq was acquired by Hewlett Packard. The last Alpha-based products were released in 2004, meaning that the ISA was effectively dead because of a series of acquisitions.
MIPS Technologies was spun out of Silicon Graphics as an independent IP company in 1998. For some years it enjoyed some success, particularly at the higher end of the processor IP market, and was only the second architecture to have Android ported in 2009. However, with a declining share price, MIPS sold 498 patents to AST and agreed to an acquisition by Imagination Technology in 2013. After Canyon Bridge acquired Imagination, MIPS was spun-out again ending up, after a series of transactions, as part of Wave Computing. As an artificial intelligence silicon provider, Wave is a potential competitor to some MIPS licensees.
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