LightSpeed C: modify-to-run in a couple of seconds (often).<p>I worked on an assembler&#x2F;editor that had a change-to-run system on the order of a couple of seconds, too.<p>Something changes when you have near instant turnaround time. It&#x27;s <i>magic</i>.<p>Some of the most miserable time I&#x27;ve spent has on projects with tooling where builds took hours, and often hours just to fail. I was even okay with 30 minute turnaround time, as long as it was clear that the bottleneck wasn&#x27;t fucking lame tools: The need to burn a bunch of EPROMs for each build, for instance . . . though I fixed that as soon as I could.