Windows 95 worked out whether a setup program had run by reading the executable's name and checking it against a short list of hard-coded words, according to Microsoft engineer and semi-official Windows historian Raymond Chen, sharing the details via his Old New Thing blog. A filename containing "setup," "install," or "inst" flagged the program as an installer, which triggered the operating system's routine for repairing system files that installers had damaged. Three non-English entries appeared on the same list, which Chen identified as his own guesses at Italian, Turkish, and Hungarian.
The full match list ran to six terms: setup, install, inst, imposta, ayarla, and felrak. Chen wrote that "install" was redundant, because any name containing it already contains "inst," and speculated that the shorter entry was added later to catch installers named along the lines of "blahinst" without anyone deleting the original. A program whose own name produced no match got a second test, with Windows 95 checking whether the word "Setup" appeared anywhere in the path to the executable. A separate live check ran after any multimedia driver was installed through an INF file, added because those drivers frequently overwrote system DLLs.
