In the nascent days of Windows 95, developers faced a unique challenge: ensuring that software installers did not inadvertently overwrite existing files with older versions. To address this, they devised a solution that was both innovative and straightforward—by making educated guesses based on the names of the programs.
Windows 95 knew if you were running an installer by taking a guess based on its name
This approach, while rudimentary, proved effective. As highlighted by Microsoft developer Raymond Chen in his blog, The Old New Thing, Windows 95 employed a simple heuristic to identify running setup programs. Instead of analyzing the actions being performed, the system scanned the program’s name for specific “magic words.” If it found a match, it flagged the program as a setup installer.
Chen shared a list of these magic words, which included:
| Magic word | Notes |
|---|---|
| setup | |
| install | Redundant |
| inst | |
| imposta | Italian? |
| ayarla | Turkish? |
| felrak | Hungarian? |
Interestingly, the word “install” was deemed redundant. Chen speculated that this was because Windows 95 could also detect variations like “inst,” which would encompass names such as “install,” “installer,” and “installation.” This clever design even allowed the system to catch truncated names like “appinst.”
Moreover, if a program lacked the word “install” in its name, Windows 95 would check the executable path for any occurrences of the magic words. Upon detecting a match, the system would conduct a post-installation verification to ensure that no newer files were replaced by older versions. While this method may seem simplistic by today’s standards, it exemplified a resourceful engineering solution given the technological limitations of the time.