John L. Henderson
March 9, 1944-Jan. 31, 2017
Los Altos, California

John Henderson of Los Altos, California, died following a five-year battle with cancer on January 31, 2017.

Born John Leslie Henderson on March 9, 1944 to Albert and Carolynne (nee Marlin) Henderson in Charlotte, North Carolina, he graduated from Myers Park High School, the University of North Carolina at Charlotte with an Associate Degree in Mathematics, and Ohio State University with a Master's of Science Degree in Computer and Information Science Engineering.

Henderson was drafted in 1966 and served as a Program Specialist in the U.S. Army Data Support Command in Washington, D.C., receiving an honorable discharge in 1972. He was awarded a Good Conduct and a National Defense Service Medal.

Henderson moved to Silicon Valley in the early 1970s, settling into a 1939 cottage in Los Altos which he remodeled and lived in for almost four decades.

He founded and ran Tall Tree Systems in Palo Alto from 1974 until 1992, where he was an early innovator of bank switching memory with the JRAM line of memory boards, which broke the 640K DOS limit and allowed the early PC systems to utilize a full 2.6MB of memory. Tall Tree's JLASER line of piggyback modules utilized JRAM memory boards to provide enough memory to print full page graphics on the original HP LaserJet Printer. According to InfoWorld (November 28, 1983) Tall Tree Systems manufactured “some of the largest memory boards available for the IBM PC.” The article went on to say that “Henderson is one of those true believers who has devoted himself to stretching the performance of the machine.” Henderson was one of the first programmers to provide open source coding so that other programmers could build on his code, rather than protecting it by patents, during what is known as the "free software movement" of the 1980s and 90s.

In addition to technology, Henderson loved the Grateful Dead – he attended 166 live performances - and the memorabilia he shared with his wife Pam was featured in the San Jose Mercury News in 2011.

He is survived by his wife Pamela Joy Lincoln of Los Altos and their beloved German Shepherd Garci Aloha, nephews Edward Thompson, Jr. (Emily), of Castle Rock, CO, Marshall Thompson (Reid) of Evergreen, CO, and Davis Thompson (Miriam) of Wilmington, NC. He was predeceased by siblings Thomas Henderson and Lynne Henderson Rich.

A private memorial will be held in early June in Los Altos.

Tags: veteran, business