October has been a deadly month for computer science types. On October 5, Apple legend Steve Jobs passed away; a week later C language creator Dennis Ritchie was found dead; and this week artificial intelligence guru John McCarthy died at the age of 84.

McCarthy had his hand in many computer science advances during his long career, but is perhaps best known for creating Lisp, a programming language that is still in wide use today. Lisp also became the premier language for exploring AI, the computer science domain that McCarthy pioneered during the latter half of the 20th century.

Lisp refers to the language’s focus on LISt Processing, in which both the data and instructions are represented as a linked lists. By being able to manipulate the code as data, Lisp provided the capability to create new custom syntaxes within the language. This feature was advertised as a way for programmers to design and implement “intelligent” computation systems. McCarthy said he designed Lisp so programmers could create Turing machines — software that reflects a level of automated intelligence bounded by a set of rules.

As a big proponent of AI, McCarthy was attributed with coining the term “artificial intelligence” in 1955. A year later, he organized the first international conference on AI, bring together the early adherents to the field, including Marvin Minsky. In these early days, artificial intelligence was oversold, as even McCarthy realized, admitting that his 1958 paper, Programs with Common Sense “made projections that no one has yet fulfilled.”

The other area of computer science that McCarthy is less well-known for is that of utility computing and time sharing. The idea of offering computing as a utility like electricity or water gained popularity in the 1960s, but faded, mostly due to lack of enabling technologies like fast networks and cheap computers. By the 21st century, both networks and compute capacity became commodities, leading to grid computing, and more recently, of course, cloud computing. Some attribute McCarthy’s early work in this area as the foundation of the public and private cloud models in use today.

Compared to Jobs and Ritchie, McCarthy’s work was much more theoretical, but it may turn out to have even broader impact on the industry. Although AI and utility computer were mostly confined to computer science research projects during most of his career, he managed to live long enough to see IBM computers beat humans at chess and then Jeopardy, and individuals to be able to buy compute cycles from a company that sells books over the internet.