Operating systems: OS, DevOps by OS, Pentesting by OS, Microsoft OS (Windows, Windows desktop: Windows 11, Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, Windows 2000, Windows ME, Windows 98, Windows NT, Windows 95, Windows for Workgroups; Windows Server: Windows Server 2022, Windows Server 2019, Windows Server 2016) Google OS (Android, Chrome OS), Apple OS (Darwin (operating system), iOS, iPadOS, macOS-OS X, tvOS, watchOS), IBM OS (IBM Z/os, IBM MVS, IBM VM/CMS); Open source operating system: Linux (Ubuntu, Linux Mint, Debian; RHEL, Rocky Linux, CentOS, Oracle Linux, Fedora); Unix, FreeBSD, ReactOS, DOS, OS/2, Awesome OS, Plan 9 from Bell Labs. (navbar_os)