text: (cid:2) Object access method (OAM): OAM is a z/OS archive storage subsystem only. Only one 
  
  OAM archive exists for each system. Scalability within the archive is achieved by 
  increasing the number of storage groups. A z/OS system can grow by increasing the 
  number of processors, amount of memory, number of disks, and I/O. If more capacity is 
  needed than can be provided by a single system, z/OS allows multiple systems to be 
  connected in a Parallel Sysplex. All of these systems then can access the same OAM 
  subsystem, therefore providing unparalleled scalability, reliability, availability, and 
  performance. 
  
  Both Tivoli Storage Manager and OAM provide hierarchical data management facilities. Data 
  can be stored on different devices based on the age or predicted frequency of data access. 
  For example, frequently accessed data might be placed on high-speed disk and infrequently 
  accessed data might be placed on tape. When the data is requested by a user, the location of 
  the data is transparent to the user. The only perceived difference from a user perspective is 
  the response time, which is mainly a factor of the type of device on which the data is stored. In 
  this example, tape access is slower than disk access. 