Editing DEC PRISM (section)

===Legacy===
By the time of the July 1988 meeting, the company had swung almost entirely into the position that the RISC approach was a workstation play. But PRISM's performance was similar to that of the latest VAX machines and the RISC concept had considerable room for growth. As the meeting broke up, [[Ken Olsen]] asked Supnik to investigate ways that Digital could keep the performance of VMS systems competitive with RISC-based Unix systems.<ref name="supnik-alpha">{{cite web |url=http://simh.trailing-edge.com/semi/ev4.html|title=EV-4 (1992)|date=2008-02-24}}</ref>

A group of engineers formed a team, variously referred to as the "RISCy VAX" or "Extended VAX" (EVAX) task force, to explore this issue.<ref name="supnik-alpha" /> By late summer, the group had explored three concepts, a subset of the VAX ISA with a RISC-like core, a translated VAX that ran native VAX code and translated it on-the-fly to RISC code and stored in a cache, and the ultrapipelined VAX, a much higher-performance CISC implementation. All of these approaches had issues that meant they would not be competitive with a simple RISC machine.{{sfn|Comerford|1992|p=28}}

The group next considered systems that combined both an existing VAX single-chip solution as well as a RISC chip for performance needs. These studies suggested that the system would inevitably be hamstrung by the lower-performance part and would offer no compelling advantage.{{sfn|Comerford|1992|p=28}}

It was at this point that Nancy Kronenberg pointed out that people ran VMS, not VAX, and that VMS only had a few hardware dependencies based on its modelling of interrupts and memory paging. There appeared to be no compelling reason why VMS could not be ported to a RISC chip as long as these small bits of the model were preserved. Further work on this concept suggested this was a workable approach.{{sfn|Comerford|1992|p=28}}

Supnik took the resulting report to the Strategy Task Force in February 1989. Two questions were raised: could the resulting RISC design also be a performance leader in the Unix market, and should the machine be an open standard? And with that, the decision was made to adopt the PRISM architecture with the appropriate modifications, eventually becoming the [[DEC Alpha|Alpha]], and began [[OpenVMS#Port to Alpha|the port of VMS to the new architecture]].<ref>{{cite web|url=https://dspace.mit.edu/bitstream/handle/1721.1/48380/managingtechnolo00katz.pdf|date=April 1993|title=Managing Technological Leaps: A study of DEC's Alpha Design Team}}</ref>

When PRISM and MICA were cancelled, Dave Cutler left Digital for [[Microsoft]], where he was put in charge of the development of what became known as [[Windows NT]]. Cutler's architecture for NT was heavily inspired by many aspects of MICA.<ref>{{cite book |last1=Zachary |first1=G. Pascal |title=Showstopper!: The Breakneck Race to Create Windows NT and the Next Generation at Microsoft |date=2014 |publisher=Open Road Media |isbn=978-1-4804-9484-8 |url=https://books.google.com/books?id=o2IkAwAAQBAJ&q=%22Dave+Cutler%22+march+13&pg=PT9 |access-date=2021-01-04|language=en}}</ref><ref>{{cite web|url=http://neilrieck.net/docs/dave_cutler-prism-mica-emerald-etc.html|title=Dave Cutler, PRISM, Mica, Emerald, etc.|author=Neil Rieck|website=neilrieck.net|access-date=2021-01-04}}</ref><ref>{{cite web|url=https://www.itprotoday.com/compute-engines/windows-nt-and-vms-rest-story|title=Windows NT and VMS: The Rest of the Story|author=Mark Russinovich|date=1998-10-30|access-date=2021-01-04|website=itprotoday.com}}</ref>