Environment Switching

In this section:

You can toggle between the XMI server and DBCTL environments by allocating the appropriate data sets and issuing the relevant SET commands. For more information about SET commands, see Implementing DBCTL.


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Switching to DBCTL From the XMI Server

If you want to switch from the XMI server environment to the DBCTL environment, you must do the following:

  1. Allocate the FOCPSB data set to ddname FOCPSB in your FOCUS address space. the identifier prefix represents the high-level qualifier for your FOCUS production libraries:

    From

    Allocation

    The CLIST that invokes FOCUS

    ALLOC F(FOCPSB) DA('prefix.FOCPSB.DATA') SHR REUSE

    A FOCUS session

    {MVS|TSO} ALLOC F(FOCPSB)  DA('prefix.FOCPSB.DATA')SHR REU

    or

    DYNAM ALLOC FILE FOCPSB DATASET prefix.FOCPSB.DATA  SHR

    Batch FOCUS JCL

    //FOCPSB  DD  DSN=prefix.FOCPSB.DATA,DISP=SHR

  2. If you are running TSO, identify the suffix for the DRA Startup Table
    ENGINE IMS SET IMSPZP nn 

    where:

    nn

    Is the suffix for the DRA Startup Table, chosen during installation (see Installation Instructions).

  3. Turn on DBCTL mode by issuing the following:
    ENGINE IMS SET DBCTL ON

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Switching to the XMI Server From DBCTL

If you want to switch from the DBCTL environment to the XMI server environment, you must do the following:

  1. Allocate a communication file to ddname FOCBMP in your FOCUS address space. You can either include this allocation in the CLIST or JCL that invokes FOCUS or you can allocate it dynamically. The Communication File in Additional Instructions for Using the XMI Server describes how to allocate a communication file.
  2. Turn off DBCTL mode by issuing the following:
    ENGINE IMS SET DBCTL OFF

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Configuring the Adapter to Support Non-stop Processing

The adapter has the ability to read IMS data in several different environments. The adapter also supports non-stop processing. This feature gives the adapter the ability to switch the access mode transparently so that reporting from IMS will continue even when one environment is not accessible. DBCTL must be installed to take advantage of this feature.

This feature works in a batch environment.

Below is a diagram that explains how this feature works.

  1. The user issues a TABLE or SQL SELECT against an IMS database.
  2. The request is passed to IMS using DBCTL, which is the default access mode.
  3. Sometime during the day, DBCTL access is terminated.
  4. The user issues another request.
  5. The adapter checks DBCTL availability and determines that DBCTL is not accessible.
  6. The request is passed to the first available DLI XMI Server for processing.
  7. When DBCTL becomes available, all requests will be passed to it for processing.

This feature can be configured on a user by user basis using the user profile.

Note:


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