I am positive about the benefits of TDD.<p>Still, sometimes I found asking myself what kind of test methodology people like Dennis Ritchie exercised? You know, inventing a programming language like C seems a colossal endeavor.<p>In general what kind of testing methodology they were using back in the day, in the "golden age" of computing.<p>Sorry if the answer for this question is heavily documented elsewhere and I didn't do a proper research prior to asking.<p>Thanks!
My programming career dates back to the '70s, so I can tell you what programmers did back then from my experience: examined core dumps, inserted "print" statements, desk-checked (manually read through) code with a colleague.<p>We didn't have debuggers per se, but we could step through code one instruction at a time and examine memory. On the PDP minicomputers you would do that from the front panel with switches and lights.<p>I had to read assembly code and dis-assemble memory contents into assembly routinely back then. I'm sure Dennis Ritchie did that too, that skill was part of the toolbox.<p>While TDD became a buzzword and cult much later, in the companies I worked at back then we often/usually had to submit a test plan with code to run the tests for any non-trivial code. At my first job (Nike, 1979) we called that code a <i>test harness</i>, more or less the same thing as modern unit tests without the automation. Most companies I worked for through the '80s would run a parallel hardware system for testing/staging, and we worked with business and systems analysts who could verify correct implementation of business rules and look for performance bottlenecks (more of an issue back then compared to today).<p>Brian Kernighan wrote a book about his days at Bell Labs that covers the development of Unix and C.
On the off chance no one here answers, maybe try asking on TUHS? <a href="https://www.tuhs.org/mailman/listinfo/tuhs" rel="nofollow">https://www.tuhs.org/mailman/listinfo/tuhs</a><p>(Doug and Ken were still posting there as of last month, and if anyone knows what Dennis' testing habits were back then, they would)