Caveat: As a member of the PL/I committee, and the person who brought the new and unimplemented language to the attention of Multics, let a disastrous contract for a compiler, and finally helped cobble together a rudimentary compiler that got the project off the ground, I am not exactly an unbiased observer. A ground tenet of Multics was that it would be programmed in a higher level language. A subsidiary requirement, which was generally agreed upon, was language-level access to the logical operators and address manipulation inherent in the hardware. No widely used language of the time met this requirement. And they didn't want to get sidetracked into language design. Discussions finally boiled down to AED, developed at MIT by Doug Ross, and PL/I. Ross was a brilliant software innovator with a mystical outlook that made it difficult to distinguish his vision of what could be done from what actually existed. AED was definitely a moving target. By contrast PL/I had a written spec, so you knew exactly what could be done in it, though not how well the compiler would do it. PL/I was very big; we deliberately (and explicitly) omitted about half the spec. The remainder was definitely seen as a "plausible systems programming language". From the perspective of the time, why do you think the contrary? Doug