What Is NOS Software?

Cisco routers use a specialized NOS.

NOS, or network operating systems, software refers to programs that allow servers to transfer data, handle user information and activate programs and devices over a network. This software comes in several major types, usually related to other popular computer operating systems. Some routers contain network operating systems that allow them to perform network functions. The term “NOS” also refers to an obsolete mainframe operating system common in the late 20th century.

Descriptions

NOS, or network operating system, software runs on a server, allowing it to manage users, user groups, network security, applications, data and other functions. Most NOS software allows shared printer and file access among networked computers, whether they're on a private network, a local area network or the Internet. Many desktop computer operating systems have limited NOS capabilities, allowing them to function as peer-to-peer network operating systems.

Types

Most standard computer operating system manufacturers also release an NOS variant of their primary product. Popular network operating systems include Microsoft Windows Server and Microsoft Windows Sever 2008. Linux distributions, such as SUSE, Ubuntu, Mandriva and Debian, often include server versions, as well. Other servers run on UNIX, Mac OS X and Novell Netware.

Routers

Some routers and firewalls use specialized network operating systems to operate functions in the network layer of the Open Systems Interconnection model, a communications system standardization model. These pieces of NOS software are usually proprietary to the router, and include Cisco IOS, and Juniper Networks JUNOS.

Considerations

In the late 1970s, Control Data Corporation produced an operating system known as NOS, for Network Operating System. Despite the similar name, this NOS software is entirely unrelated to server-based network operating systems. CDC's NOS ran on the CDC 6000 series of 60-bit mainframe computers and provided time-sharing capabilities. It replaced the older CDC Kronos operating system and was meant to run on all machines produced by the company. NOS was eventually replaced by the NOS/VE operating system for 64-bit Cyber 180 mainframe computers, about a decade after its debut.

References

• PC Magazine Encyclopedia: Network Operating System
• Florida Center for Instructional Technology: What Is a Network Operating System?
• Control Data Corporation: NOS Version 1 Reference Manual
• ServerWatch: The Top 10 Linux Server Distributions
• Webopedia: The 7 Layers of the OSI Model
• Network World: The Battle Between JUNOS and IOS