Thirty-six years ago this month, HP put a reboot of its business future into orbit. The project called Spectrum was the entry of PA-RISC (originally called "HP High Precision Architecture") when publicly announced in the HP Journal in 1985. HP brought the future into the light by killing its Vision project at the 1984 Interex user conference.

Stan Sieler, one of the founders of Allegro, was working at HP in the years before the HP announcement of what the company called High Performance Precision Architecture RISC. "A year or so later, when it was simply called PA-RISC (or HP PA-RISC), I asked Joel Birnbaum what happened to the "High" and I was ignored. Along with Bill Worley, these were the fathers of RISC inside HP. Birnbaum had been recruited from IBM's RISC project."

Digital was famous for raining on HP's Reduced Instruction Set Computing, as well as Unix, during the time PA-RISC rose up. Ken Olsen, DEC's founder, pulled the plug in 1989 on Prism, Digital's RISC computer design. HP struggled to get its business servers onto PA-RISC, managing to put its Unix onto the new architecture first. Digital tried to make inroads by touting its 32-bit VAX processors versus the 16-bit HP 3000 classic servers. "Digital has it now," the ads in the trade weeklies proclaimed.

Sieler says that several other companies were incensed at HP having a product called Spectrum, including Chevrolet. "I remember hearing reports of some legal actions against HP, which were reportedly dropped after HP promised to never use that term externally. That is apparently why we titled our book about PA-RISC Beyond RISC instead of Beyond Spectrum. We were told HP wouldn't buy any copies if we had "Spectrum" on the cover. But we did sneak it in: the spectrum is the photo."

RISC was designed to consolidate the development of peripheral interfaces for all all three of its computer lines: HP 3000, HP 9000s, and its real-time systems the HP 1000s. About late 1986, the real time version of HP-UX on PA-RISC —  demonstrated at the 1986 Madrid Interex conference on an HP 9000/840 — was quietly dropped. "We used to have an HP publication about real time support for HP-UX, but I think it went to the Living Computer Museum in Seattle when we gave them our manuals about two years ago," Sieler said.