The installed OS on the Symbolics machine was only a few hundred megs, from long-vague memory. Much of that was a huge set of documentation. I would venture to

The installed OS on the Symbolics machine was only a few hundred megs, from long-vague memory. Much of that was a huge set of documentation. I would venture to say that the MIT AI/Symbolics Lisp machine development crew (Rick Greenblatt, Dave Moon, Howard Cannon, Mike McMahon, Daniel Weinreb, sometimes RMS, and a not-too-large cast of others) probably developed the most powerful operating system (written entirely in Lisp), compressed over the shortest time period in history for any comparable project. I don't think the tools they developed, and were using for their own further development, have been equalled since. (Which is kind of sad, in a way.)