Server Operating System

A server operating system (Server OS) is a type of operating system that is designed to be installed and used on a server computer. It is an advanced version of an operating system, having features and capabilities required within a client-server architecture or similar enterprise computing environment. Some of the key features of a server operating system include:

Ability to access the server both in GUI and command-level interface
Execute all or most processes from OS commands
Advanced-level hardware, software and network configuration services
Install/deploy business applications and/or web applications
Provides central interface to manage users, implement security and other administrative processes
Manages and monitors client computers and/or operating systems^[1]

Most Popular Server Operating Systems^[2]
Popular server operating systems include Windows Server, Mac OS X Server, and variants of Linux such as Red Hat Enterprise Linux (RHEL) and SUSE Linux Enterprise Server. According to SpiceWorks, this list is the most deployed on-premises server operating systems (August 2016):

Windows Server 2003
Windows Server 2008
Windows Server 2012
Linux (excluding RHEL)
Windows Server 2000
Red Hat Enterprise Linus (RHEL)
Mac OS X Server

Types of Server Operating Systems^[3]
The server operating system is also called the network operating system, which is the system software that the server can run. Almost all servers can support various operating systems. It means, HPE servers and Dell servers both support these four types of server operating systems. Here are overviews of four mainstream server operating systems.

UNIX operating system: UNIX was originally a time-sharing operating system supporting small computers, but eventually became one of the most popular server operating systems in a client-server environment. It is written in C language, and because the C language abbreviator supports many different platforms, compared with other operating systems, UNIX has been ported to a wider range of machines. UNIX is designed for a multi-user environment, the so-called multi-user operating system, and has built-in TCP/IP support, with good stability and security. At present, more than 90% of various sites that provide services on the Internet use the UNIX operating system. Unlike other operating systems, different vendors sell different versions of UNIX, and there is no real UNIX. On the contrary, although people try to develop a standard UNIX version, there are actually many different versions that are similar and incompatible.
Linux operating system: Linux is a kind of free software, which has all the functions of UNIX. Originally developed by students of Finnish universities, version 0.11 was released in 1991. Linux is an excellent operating system. It is open, supports multi-user, multi-process, multi-thread, good real-time performance, powerful and stable, and can be obtained for free under the GPL organized by the CNU Free Software Foundation. A POSIX-compliant operating system. This operating system software package also includes application software such as a text editor and a high-level language compiler, allowing the use of windows, icons and menus to operate the system.
Netware operating system: The NetWare system is a server-based network operating system, which requires a dedicated server in the network. The NetWare operating system was commonly used in early computer networks. NetWare series operating systems can support multi-processor and large-capacity physical memory management; can provide shared file access and printing functions; support the high scalability of corporate networks, including open standards and file protocols.
Windows operating system: The Windows series of operating systems include different series such as Windows 2000 and Windows 2003, which are mainly network operating systems used for servers in the network. The Windows series of operating systems can support symmetric multi-processor systems, large-capacity memory management, and unique file and file management systems, and are also deeply loved by users.

Difference between Server OS and Client OS^[4]

Client OS: It is an operating system that operates within desktop. It is used to obtain services from a server. It run on the client devices like laptop, computer and is very simple operating system.
Server OS: It is an operating system that is designed to be used on server. It is used to provide services to multiple client. It can serve multiple client at a time and is very advanced operating system.

Server Operating System	Client Operating System
It can be used to provide services to multiple client.	It can obtain services from a server.
It can serve multiple client at a time.	It serves a single user at a time.
It is complex operating system.	It is simple operating system.
It runs on the server.	It runs on the client devices like laptop, computer etc.
It is an operating system that is designed to be used on server.	It is an operating system that operates within desktop.
It provides more security.	It provides less security.
It has greater processing power.	It has less processing power.
It is more stable.	It is less stable.
It is highly efficient.	It is less efficient.
Examples: Red Hat, Linux.	Examples: Windows, Android.

Selecting a Server Operating System^[5]
There are many factors that should be taken into consideration in the selection of a server operating system. They include determining the amount of money one can afford to spend, the hardware requirements of the system, the applications that are included or "bundled" into the software, the power of the hardware and the system, security, scalability, administrative tools available and options to install third-party programs. Consideration of administrative tools and knowledge of how to use them also is important because a server operating system does not tend to be nearly as user-friendly as systems for non-commercial, single-user purposes are.

If the number of requests that client computers will be making of the server is very high, a very powerful server that can run on hardware with a very large storage capacity and multiple processors usually is needed to prevent downtime. Other hardware considerations are dictated by the specific server operating system of choice. Stability also is of extreme importance; if a web server hosting a commercial website breaks down, a company's sales could plummet and affect profits. Consideration of the availability of crucial applications that can run under the server operating system also is very important because if what is needed is not included, there will be the need to install third-party programs to satisfy computing needs such as the handling of company emails.

Common applications for Server Operating Systems^[6]

File and printer sharing: File sharing involves setting up a common storage point for a company's documents - a network drive, as it were. Print sharing allows multiple computers to use a single printer. Windows 95, 98 and ME do have file and print sharing, but are not recommended for use as server OSes.
Application services (including databases): a server OS's ability to run the applications you need is obviously crucial. Servers function as crucial database stores and shared environments for collaborative applications (such as networked MYOB or Quicken).
Web site services: A hypertext transfer protocol (HTTP) server is included with many server OSes, either via an integrated application, or other HTTP applications such as the Apache open source server. Some OSes also come with more advanced features, such as database integration (so you can dynamically build Web pages based on information in a database), personalisation and scripting. The world's most popular HTTP server application, Apache, comes with just about every version of Unix and also runs on Windows. Microsoft provides Internet Information Server (IIS) for Windows platforms.
E-mail, groupware and messaging: A central e-mail server allows you to forward and receive e-mails to and from your business, as well as control individual e-mail accounts based on a domain. Groupware applications, such as Lotus Notes, Microsoft Exchange or Novell GroupWise, provide email as well as much more sophisticated collaboration. These applications can include shared calendars, document version management, group forums, database/messaging integration, instant messaging and whiteboard sharing. Open source mail systems such as SendMail and Exim are also popular.
Terminal services: Allow a client to run a productivity application on a server, while seeing the visual results of the application on their screen. For instance, a client ('terminal') could be running Microsoft Word on the server from their desktop. The server does all the processing work, and just transmits the graphical changes to the terminal, while taking the user's input (mouse movements and key strokes) and sending them to the server. This model allows a company to use clients that don't have a lot of processing power (and enforces the storage of documents on the server, rather than on local hard drives). A server with a lot of memory and a fast processor is needed if it's going to be running productivity applications for the whole office. Nearly every current server OS can do this via Windows Terminal Server, Citrix MetaFrame or the X Window System (which is used by Novell and just about every Unix variant).
Caching: Speeding up network access (usually Internet access) by storing previously downloaded files in a cache - kind of like the way an Internet browser keeps a cache of the Web pages you have visited so it doesn't have to download the files all over again. Examples of caching server applications include Novell BorderManager, Microsoft Internet Security and Acceleration Server, Inktomi Traffic Server and Squid.

Server Operating System

See Also