The Unix-Haters Handbook also has a story about backcompat: > Way back in the early 1980s, before each of the bugs in Unix had such a large cult following, a p

The Unix-Haters Handbook also has a story about backcompat: > Way back in the early 1980s, before each of the bugs in Unix had such a large cult following, a programmer at BBN actually fixed the bug in Berkeley’s `make` that requires starting rule lines with tab characters instead of any whitespace. It wasn’t a hard fix—just a few lines of code. > Like any group of responsible citizens, the hackers at BBN sent the patch back to Berkeley so the fix could be incorporated into the master Unix sources. A year later, Berkeley released a new version of Unix with the `make` bug still there. The BBN hackers fixed the bug a second time, and once again sent the patch back to Berkeley. > …The _third_ time that Berkeley released a version of `make` with the same bug present, the hackers at BBN gave up. Instead of fixing the bug in Berkeley `make`, they went through all of their Makefiles, found the lines that began with spaces, and turned the spaces into tabs. After all, BBN was paying them to write new programs, not to fix the same old bugs over and over again. > (According to legend, Stu Feldman didn’t fix `make`’s syntax, after he realized that the syntax was broken, because he already had 10 users.)