The following types of OS installed on hosts are possible:

        -1  - P_UNKNOWN        - Unknown
         0  - P_DOS            - MSDOS, Windows 3.xx, Windows 9x/Me
         1  - P_OS2            - OS/2
         2  - P_NT             - Windows NT/2000/XP/2003/Vista
         3  - P_OSF            - OSF
         4  - P_VMS            - VMS
         5  - P_NOVELL         - Novell
         6  - P_LINUX          - Linux
         7  - P_FREEBSD        - BSD
         8  - P_WIN_MOBILE     - Windows Mobile
         9  - P_SYMBIAN_MOBILE - Symbian Mobile
         10 - P_MAC            - MAC OS
         11 - P_BLACKBERRY     - BlackBerry OS
         12 - P_ANDROID        - Android OS
         13 - P_IOS_MOBILE     - iOS 
         14 - P_WIN_PHONE      - Windows Phone OS
         15 - P_UEFI_EMBEDDED  - UEFI embedded
         16 - P_KASPERSKY_OS   - Kaspersky OS

See also:

Computer query format