Over the past five decades, computer scientists have built increasingly intuitive programming languages, making it easier and easier for people to create software for desktops, laptops, smartphones, cars and even supercomputers. Compilers ensure that these languages are efficiently translated into the ones and zeros that computers understand.
Without their work, “we would not be able to write an app for our phones,” said Krysta Svore, a researcher at Microsoft who studied with Mr. Aho at Columbia University, where he was chairman of the computer science department. “We would not have the cars we drive these days.”
The researchers also wrote many textbooks and taught generations of students as they defined how computer software development was different from electrical engineering or mathematics.
“Their fingerprints are all over the field,” said Graydon Hoare, the creator of a programming language called Rust. He added that two of Dr. Ullman’s books were sitting on the shelf beside him.
After leaving Princeton, both Dr. Aho, a Canadian by birth who is 79, and Dr. Ullman, a native New Yorker who is 78, joined the New Jersey headquarters of Bell Labs, which was then one of the world’s leading research labs.