Testing algorithms using the SB Test utility (DFSSBHD0)

When you run the SB IMAGE CAPTURE option of the DFSSBHD0 utility, the same sequential buffering (SB) handler call sequence (which is issued during the processing of a specific application) captures on the IMS log all internal IMS calls to the SB buffer handler You can use this utility to investigate and test behaviors of various algorithms.

The DFSSBHD0 utility with the SB IMAGE CAPTURE option is useful for investigating:

• The SB I/O reference pattern analysis algorithms
• The impact of changes to user-specifiable SB parameter values (the BUFSETS parameter value)

Running the same SB buffer handler call sequence multiple times is useful in the following situations:

• You need to use the SBSNAP option but do not know when to Start or Stop the SBSNAP option.
• You want to experiment with different SB algorithm parameters and observe the impact of these changes on the //DFSSTAT statistics.
• You want to test changes to the SB I/O reference pattern analysis algorithms and observe the impact of these changes on the //DFSSTAT statistics.

You activate the SB IMAGE CAPTURE option by providing a SBIC control statement in the //DFSCTL file.