Earlier quoted context omitted.
> The compiler is part of the IDE, not some external process that needs to start from a blank state for each file, needing to read the same files over and over... I suspect the difference is negligible in practice. In both cases, the files are likely to be cached in memory after they're read the first time, so you're not really reading it over and over.
Probably, but it can be a convenience to make some small modifications to try out things without saving them. From a performance standpoint the win comes from not having the compiler start from a blank state for each file but keep the compiled objects in memory and only update the changed files. I suppose a modern reimplementation of that idea (that has more memory to spare, after all the official BC++5 requirements…
Yes, I remember it being very pleasant when borland C++ crashed after running your application, losing your unsaved work.
edit: that was on windows 95/98 time; so it is more likely that the application crashed the whole OS.