All servers run on an operating system that enable the computer to perform its core functions as a server.  These are some of the most popular server operating systems.
   



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Windows Server is designed for large or small networking environments.  They are well supported with frequent updates and patches and Microsoft customer support.

Microsoft Servers comes as different versions:

Server 2008 R2:  This was officially released February 27, 2008.  It replaced the Windows 2003 Server.  The most current version is Windows Server 2008 R2 which was released July 22, 2009.  The enterprise version is intended for companes with more than 75 users and supports 64bit processing.

Cost:  
- Standard: $725.00
- Enterprise: $2,495

Server 2008 Small Business:  This is for companies with less than 75 users.  It comes bundle with Microsoft Exchange (for email hosting) and SQL server (for database hosting).

Cost:  
- $995.00 (20 user license)
- $325.00 (5 user license)

 

Server 2012 Standard:  This was released September 4, 2012.  It replaces Windows Server 2008 R2.  Supports cloud computing and 64bit processing.  It can support up to 64 processors and 1 terabyte of memory.  It can support up to 64 terabytes of hard disk capacity.  You can perform virtualization and manage other platforms as well as secure data on any computer on the network.

Cost:  $1,298.00

Windows Server 2012 Essentials:  This versionis for small businesses with less than 25 users.

Cost:  $501.00 (5 user license)

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  Open Enterprise Server 11:  Released December 13, 2011.  Supports windows, mac and Linux cleint computers.  Runs on linux platform.  Supports file & print sharing and network management.

Cost: $197.00 per license
   
   
  Solaris 11:  Released by Oracle November 9, 2011.  This is an UNIX based operating system that supports x86 based computers.  It has virtualization and cloud support.  It has built-in data services such as deduplication, encryption, replication, compression. 

Cost: 
   
   

OS X 10.8 (Mountain Lion):  Released July 25, 2012.  This is an Apple operating system.  This is the same operating system used on the client computer that is converted to the server version by downloading an app from the Mac App Store for $19.99, that includes a server management app called Server, as well as other additional administrative tools to manage clients.  It comes with unlimited client licenses, and once purchased can be run on an unlimited number of machines.

 

Cost:  $19.99  for app (OS comes with computer you purchase)