Windows 95 identified software installers by scanning program names for specific keywords rather than using a sophisticated detection system [1].

This revelation highlights the rudimentary nature of early operating system security and the reliance on heuristics to manage system-file recovery. Understanding these legacy methods provides insight into how modern OS protections evolved from simple string matching to complex digital signatures.

Raymond Chen, a Microsoft veteran, said that the operating system did not truly detect installers in the modern sense [2]. Instead, the system employed a basic trick to identify files that might be modifying the OS [4]. According to Chen, the process was a string-matching heuristic designed to protect system files from unauthorized modifications [1].

"It simply checked for words like setup, install, inst, or localized equivalents," Chen said [1].

To execute this process, the system checked for six specific terms [1]. These included "setup," "install," and "inst," as well as localized versions such as "imposta," "ayarla," and "felrak" [1]. If a running program's file name contained any of these strings, Windows 95 assumed the program was an installer [1].

This method allowed the OS to make a calculated guess about the nature of a program without requiring a formal registration process or complex metadata [2]. By identifying these files, the system could better manage the risks associated with altering core system files during a software installation [3].

“"It simply checked for words like setup, install, inst, or localized equivalents"”

The use of simple keyword matching in Windows 95 illustrates a period of computing where software trust was based on naming conventions rather than cryptographic verification. This lack of rigorous validation made early systems vulnerable to naming exploits, eventually necessitating the development of the secure, signed driver and installer frameworks used in contemporary operating systems.