Operating Systems and Subsystems

Operating system and subsystem software includes the machine-level instructions and general-purpose functions that control the operation and use of CPU resources (both centralized and networked). These operating systems quite often also include network services such as Dynamic Host Configuration Protocol (DHCP) for IP address assignment, distributed naming services (DNS) software (which provides a shared database of system resources and access control information), and directory service software (such as Microsoft's Active Directory), as well as other integrated network facilities such as print and file services. Representative vendors and products include the following:

• HP (HP-UX)
• IBM (z/OS, OS/390, i5, OS/400, and AIX)
• Microsoft (Windows XP and Windows Server 2003, as well as older Windows products)
• Novell (Novell SUSE LINUX Enterprise Server and Novell Linux Desktop)
• Red Hat Linux (Red Hat Enterprise Linux AS, Red Hat Enterprise Linux WS, and Red Hat Desktop)
• Sun Microsystems (Solaris)