Editing DEC Alpha (section)

===PRISM===
{{main|DEC PRISM}}
Alpha emerged from an earlier RISC project named Parallel Reduced Instruction Set Machine ([[DEC PRISM|PRISM]]), itself the product of several earlier projects. PRISM was intended to be a flexible design, supporting Unix-like applications, and Digital's existing VAX/VMS software, after minor conversion. A new [[operating system]] named [[DEC MICA|MICA]] would support both [[ULTRIX]] and VAX/VMS interfaces on a common [[Kernel (operating system)|kernel]], allowing software for both platforms to be easily ported to the PRISM architecture.<ref name="mica-business-plan">{{cite web|url=http://www.bitsavers.org/pdf/dec/prism/mica/Mica_Software_Business_Plan_Mar87.pdf|title=MICA Software Business Plan|author1=Catherine Richardson|author2=Terry Morris|author3=Rockie Morgan|author4=Reid Brown|author5=Donna Meikle|date=March 1987|access-date=2021-01-04|website=bitsavers.org|archive-date=2021-01-07|archive-url=https://web.archive.org/web/20210107155539/http://www.bitsavers.org/pdf/dec/prism/mica/Mica_Software_Business_Plan_Mar87.pdf|url-status=live}}</ref>

Started in 1985, the PRISM design was continually changed during its development in response to changes in the computer market, leading to lengthy delays in its introduction. It was not until the summer of 1987 that it was decided that it would be a [[64-bit computing|64-bit]] design, among the earliest such designs in a [[microprocessor]] format. In October 1987, [[Sun Microsystems]] introduced the [[Sun-4]], their first [[workstation]] using their new [[SPARC]] processor. The Sun-4 runs about three to four times as fast as their latest [[Sun-3]] designs using the [[Motorola 68020]], and any Unix offering from DEC. The plans changed again; PRISM was realigned once again as a 32-bit part and aimed directly at the Unix market. This further delayed the design.<ref name="microprism">{{cite web |first= Bob |last= Supnik |url= http://simh.trailing-edge.com/semi/uprism.html |title= MicroPrism |date= 24 February 2008 |website= The Computer History Simulation Project |access-date= 26 April 2021 |archive-date= 3 April 2021 |archive-url= https://web.archive.org/web/20210403101425/http://simh.trailing-edge.com/semi/uprism.html |url-status= live}}</ref>

Having watched the PRISM delivery date continue to slip, and facing the possibility of more delays, a team in the Palo Alto office decided to design their own workstation using another RISC processor. After [[due diligence]], they selected the [[R2000 (microprocessor)|MIPS R2000]] and built a working workstation running Ultrix in a period of 90 days.<ref>{{cite web |url=http://alasir.com/articles/alpha_history/prism_to_alpha.html |title=Alpha: The History in Facts and Comments |access-date=2019-09-09 |date=2007-04-22 |first=Paul V |last=Bolotoff |archive-date=2019-09-29 |archive-url=https://web.archive.org/web/20190929230557/http://alasir.com/articles/alpha_history/prism_to_alpha.html |url-status=live}}</ref> This sparked off an acrimonious debate within the company, which came to a head in a July 1988 management meeting. PRISM appeared to be faster than the R2000, but the R2000 machines could be in the market by January 1989, a year earlier than PRISM. When this proposal was accepted, one of the two original roles for PRISM disappeared. The decision to make a VMS PRISM had already ended by this point, so there was no remaining role. PRISM was cancelled at the meeting.<ref>{{cite web |title=Sketch of DEC PRISM |author=Mark Smotherman |url=https://people.cs.clemson.edu/~mark/prism.html |quote=PRISM (Parallel Reduced Instruction Set Machine) ... first draft of PRISM architecture in August 1985; DEC cancels the project in 1988 in favor of a MIPS-based ... |access-date=2018-09-20 |archive-date=2020-04-04 |archive-url=https://web.archive.org/web/20200404100105/https://people.cs.clemson.edu/~mark/prism.html |url-status=live}}</ref>