"Ken Thompson was undoubtedly the original moving spirit for Unix, but Dennis Ritchie was in on it from the start. And it is Dennis we have to thank for the C language. C made Unix easy to modify and, eventually, easy to install on new hardware. With hindsight, one might view C as a distillation of previous practice. Not so. Dennis discussed at length the puzzle of how to fully exploit byte-addressed machines. He finally came up with a beautiful way to reconcile address arithmetic with indexing -- one of those inventions that is so right that once you see it, you think you always knew it. The rightness of C is further attested by the fact that while Unix spread to all kinds of computers, C and its descendents spread even further. C became the language of choice for implementing all kinds of system software, both in and outside of Unix shops. C even influenced hardware architecture: Proposed instruction sets came to be evaluated partly on the basis of how well they could be exploited by a C compiler.
"Ritchie and Thompson made an amazing team; and they played Unix and C like a fine instrument. They sometimes divided up work almost on a subroutine-by-subroutine basis with such rapport that it almost seemed like the work of a single person. In fact, as Dennis has recounted, they once got their signals crossed and both wrote the same subroutine. The two versions did not merely compute the same result; they did it with identical source code. Their output was prodigious. Once I counted how much production code they had written in the preceding year -- 100,000 lines. Prodigious didn't mean slapdash. Ken and Dennis have unerring design sense. They write code that works, code that can be read, code that can evolve."
Peter Neumann remembers Joe Ossanna, who died in 1977:
"Joe and Stan Dunten at MIT were the two people with the deepest experience on input-output system issues. They became the go-to folks at Bell Labs and MIT for the Multics I/O subsystem, in addition to what it had to do in order to fit in with the rest of Multics.
"Joe had an amazing grasp of everything in that area. He was invaluable to the Multics effort. He was also a warm and thoughtful person. I miss him very much."
Douglas McIlroy shares vivid memories from the Unix lab:
"Personal high for me was the introduction of pipes -- a story that's often been told. I had been smitten with stream processing back in 1964 when Conway published the idea of co-routines. I had lobbied for direct process-to-process IO for some time, but only when I came up with the catchy name, 'pipe' and suggested a workable shell syntax did Ken Thompson vow to do it. It happened overnight and, the next day, we had a wonderful orgy of 'look at this one.' Within a week, even our secretaries were using pipes as if the feature had always been there.
"The birth of C, which I think can fairly be called the baseline workhorse language even today -- it is the implementation language for myriad other languages and systems.
"I don't know the counts of Unix and Linux servers. I do know that my heart sinks whenever I look under the hood in Linux. It is has been so overfed by loving hands. Over 240 system calls! Gigabytes of source! AC compiler with a 250-page user manual (not counting the language definition)! A simple page turner, 'less,' has over 40 options and 60 commands! It's proof that open source can breed monsters just like the commercial pros. Miraculously, though, this monster works."
Peter Neumann explains the etymology of Unix: