IMS Commands

The IMS commands affect the operation of DB2 and IMS/TM. IMS commands must be issued from a valid terminal connected to IMS/TM, and the issuer must have the appropriate IMS authority. Consult the IMS manuals in the following list for additional information on IMS commands:

SG24-5352, IMS Primer

SC27-1284, IMS V8 Administration Guide: System

SC27-1285, IMS V8 Administration Guide: Transaction Manager

GC27-1301, IMS V8 Messages and Codes, Volume 1

GC27-1302, IMS V8 Messages and Codes, Volume 2

SC27-1304, IMS V8 Operations Guide

SC27-1307, IMS V8 Summary of Operator Commands

GC27-1305, IMS V8 Release Planning Guide

The following IMS commands pertain to DB2:

/CHANGE	Resets in-doubt units of recovery
/DISPLAY	Displays outstanding units of recovery or the status of the connection between IMS/TM and the DB2 subsystem
/SSR	Enables the user to issue DB2 environment commands from an IMS/TM terminal, for example: /SSR -DISPLAY THREAD (*)
/START	Enables the connection between IMS/TM and an active DB2 subsystem
/STOP	Disables the connection between IMS/TM and an active DB2 subsystem
/TRACE	Enables and disables IMS tracing

IMS Command Guidelines

The following techniques are useful when issuing IMS commands that impact DB2.

Control the Use of Critical IMS Commands

The /CHANGE , /START , and /STOP commands should be secured commands. Because these commands can damage IMS/TM transactions that are being processed , they should be avoided during peak processing times. A centralized authority consisting of only systems programmers and DBAs should administer and invoke these commands.

Use /START and /STOP to Refresh the IMS-to-DB2 Connection

The /START and /STOP commands can be used to refresh the IMS to DB2 subsystem connection without bringing down IMS/TM.

Use /TRACE with Caution

The /TRACE command should be issued only by a qualified analyst who understands the ramifications of IMS tracing. This is usually best left to the IMS DBA or systems programmer.