This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. If an article link referred you here, you might want to go back and fix it to point directly to the intended page.
The Alef programming language was designed by Phil Winterbottom of Bell Labs as part of the Plan 9 operating system.
In a February 2000 slideshow, Rob Pike noted: "…although Alef was a fruitful language, it proved too difficult to maintain a variant language across multiple architectures, so we took what we learned from it and built the thread library for C."
Plan 9 from Bell Labs - The original environment were Alef was developed.