Irene Watson and Gary Kildall

This page was most recent revised date July 30 2014.


Irene Watson contacted me in mid-March of 2014, to correct and update my information on Signetics' PLuS programming language for their 2650 microprocessor. As a former colleage of Kildall, she knew first-hand of Kildall's work on that "port" of PL/M, as she recounted to me. She came across my accounts of PL/M like products and offered a correction.

"Gary Kildall did in fact develop the PLuS computer programming language for Signetics for their 2650 microprocessor. I know because Gary and I were both consultants to Signetics in the mid-70s and one of my tasks there was to develop a PLuS training course for customer engineers to be ready as soon Gary finished development of the language. That required Gary and I to work closely together during this period, which we did. As a result we became good friends."

Irene described her background as well: "My computer engineering background spanned over 35 years starting in the mid-60s with large mainframe systems in process control and then satellite control, then in the 70s in microprocessors and in the 80s on Stanford EE research staff and in the development of EDA (electronic design automation). You can read more about me on and at [a published newspaper account about her current activities]. - Irene Marie (Kuch) Watson". As of 2014 she has a blog at this linked site. She's working on her biography, but permited me to publish our correspondence on my site.

Later, she provided to me a resume; an IEEE paper from 1975 which compared microprocessor software tools; and some notes from her memoir in progress, about her microprocessor work of the 1970's, including with Kildall.

The IEEE paper is "Comparison of Commercially Available Software Tools for Microprocessor Programming" from Proceedings of the IEEE for June 1976 (Vol 64, No. 6, p 910 following). The paper covers several processors of the era and describes resident and non-resident tools such as assemblers, editors, simulators. The paper compares syntatical and symbol-handling features of assemblers and suggests a list of featurers for such tools.

In her notes about her work, she starts with work at Omron in 1973-4 in or near Santa Clara, CA, on Omron's 8008-based video terminal. The code was cross-assembled on a PDP-11. She became an instructor at Santa Clara university and became a training consultant for teaching microprocessor programming and development. In early 1975 Signetics contracted her to train their customers on the Signetics 2650; later she trained Phillips Semiconductor staff on that processor.

In 1976 Signetics asked Irene to develop a training coure on the PLuS language for the 2650; Kildall was developing the compiler at the time. Irene worked closely with Kildall and made test code to test PLuS for bugs. Their work was completed in June 1976. She also taught 2650 development for Phillips in that year.

Irene was active in the Asilomar Microcomputer Workshop from its founding in 1975. This was a by-invitation annual event which included Kildall and other Silicon Valley leaders in microprocessor and later LSI development. She last saw Kildall there in the early 1980's. It's still a signifigant event in the 21st century. In fact, for their 40th Workshop in 2014, The AMW commerated the IEEE's Milestone Award to Gary Kildall on the 40th anniversary of the first operation of CP/M.

My thanks to Irene Watson for preserving her work and for providing more information about microcomputer development in the 1970's.

- Herb Johnson, July 2014