Environment Switching

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

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 dataset 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
Batch FOCUS JCL or MSO server JCL	//FOCPSB DD DSN=prefix.FOCPSB.DATA,DISP=SHR
An MSO or FOCUS session	DYNAM ALLOC FILE FOCPSB DATASET prefix.FOCPSB.DATA SHR

2. If you are running TSO, identify the suffix for the DRA Startup Table (if you are running MSO, this setting is included in your configuration file, as described in Installation Instructions)

   {MVS|TSO} 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:

   {MVS|TSO} IMS SET DBCTL ON

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 in your MSO server JCL) 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:

   {MVS|TSO} IMS SET DBCTL OFF

Configuring the IMS Interface to Support Non-stop Processing

The IMS Interface has the ability to read IMS data in several different environments. The current release of the IMS Interface has been enhanced to support non-stop processing. This enhancement gives the Interface 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.

Although this feature works in a batch environment, it is geared towards an MSO 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 via DBCTL which is the default access mode.

3. Sometime during the day, DBCTL access is terminated.

4. The user issues another request.

5. The IMS Interface 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 to route all requests to MSO or it can be configured on a user by user basis using the user profile.

To enable this feature, modify your MSO configuration file as shown in Installation Instructions.

Note:

• Allocate the required IMS databases to each XMI Server. This is necessary to assure that the users have access to the same data that they had through DBCTL.
• If you wish to force this type of processing on all users that log on to MSO, place the following SET command in the FOCPARM member in your ERRORS PDS:

SET IMSNONSTOP=ON 

• You can also set this processing option on a user-by-user basis by placing the following SET command in the user's profile:

TSO IMS SET NONSTOP ON