text: **2.5 Implementing a Content Manager OnDemand instance on**
  
  **z/OS**
  
  Instances on z/OS do not differ greatly from instances on Multiplatforms. The concept is the 
  same. In this section, we explain how to set up a new instance and provide background 
  information about the UNIX System Services implementation. Always refer to the product 
  documentation of your release for the specific steps to follow. 
  
  Before you set up your z/OS instance of Content Manager OnDemand, understand the 
  different types of configurations and the components that make up the Content Manager 
  OnDemand instance. A source for determining this information is the*IBM Content Manager*
  *OnDemand for z/OS - Introduction and Planning Guide*, SC19-365. 
  
  *Instances*are logical implementations for the separation of administration functions, users, 
  and data on the same server. Instances have the same physical access to the program 
  libraries, but they have different databases with a separate system log and separate file 
  systems. Instances are typically used to separate different customers on one z/OS server to 
  separate the test and production environments, or to use different code pages on different 
  databases. 
  
  A Content Manager OnDemand instance on a z/OS server is a separately started task 
  (ARSSOCKx) that uses different databases, users, and application groups. Every user on the 
  instance must be defined for the instance. Every instance has its own security if internal 
  security is used. If an external security exit is used, it is common over all of the instances. 