Operating systems contain many files that are essential for booting, hardware support, security enforcement, and core services. These are generally referred to assystem files. Textbooks explain that system files are often protected by permissions and special attributes because accidental modification or deletion could destabilize the OS, break device drivers, prevent applications from running, or even stop the machine from booting. Therefore, standard (non-administrator) users are typically restricted from accessing or altering them, and the OS may hide them by default to reduce the risk of user error.
Examples include kernel-related components, shared libraries, driver files, configuration databases, and critical service executables. Modern OS designs enforce protection through user accounts, access control lists, and privilege separation. This ensures only trusted processes and administrators can change system-critical components.
Log files record events and are sometimes protected, but many logs are readable by users or administrators depending on policy; they are not necessarily “meant to be inaccessible” in the same strict sense. Backup files are important for recovery but are not inherently system-critical for day-to-day operation, and their accessibility depends on organizational policy. “Extension files” is not a standard category; file extensions describe formats rather than a protected functional class.
Thus, the files intended to be inaccessible to standard users yet critical for functionality are system files, reflecting core OS security principles such as least privilege and integrity protection.
