Multiple access to libraries

Multiple access to libraries occurs when several users access the same library at the same time, either in read or in write mode. The accesses can be made from within different tasks and the tasks can be assigned to different user IDs.

Multiple access to libraries is permitted only for those users who have the appropriate access right.

A library can be opened by one or more users in write mode as well as in read mode.

Below is a summary of the limiting conditions under which multiple access is possible:

• Libraries on public volume set (PVS)
  Unrestricted multiple access is possible, provided

  • the necessary access rights have been granted

  • access is not via Remote File Access (RFA)

• Libraries on shared public volume set (SPVS)

  Unrestricted multiple access is possible, provided

  • the necessary access rights have been granted,

  • access is not via Remote File Access (RFA), and

  • all accessing tasks from the various computers form a HIPLEX cluster.

• Libraries on shared private disk (SPD)
  Unrestricted multiple access is possible, provided

  • the necessary access rights have been granted,

  • access is not via Remote File Access (RFA), and

  • all accessing tasks are running on the same computer. If tasks are accessing from different computers, only read accesses are possible simultaneously. If the library is being write-accessed by a task, it cannot be accessed by tasks from other computers.