Using SB in an online system

To allow the use of SB in an online IMS or DBCTL environment, an IMS system programmer must explicitly request that IMS load the SB modules. This is done by putting an SBONLINE control statement in the DFSVSMxx member.

By default, IMS does not load SB modules in an online environment. This helps avoid a noticeable increase in virtual storage requirements.

The two forms of the SBONLINE control statement are:

SBONLINE
 
  or
 
SBONLINE,MAXSB=nnnnn

where nnnnn is the maximum storage (in kilobytes) that can be used for SB buffers.

When the MAXSB limit is reached, IMS stops allocating SB buffers to online applications until terminating online programs release SB buffer space. By default, if you do not specify the MAXSB= keyword, the maximum storage for SB buffers is unlimited.

Detailed instructions for coding the SBONLINE control statement are contained in IMS Version 15 System Definition.