Dynamic and static PSBs

A PSB (Program Specification Block) is a load library member that defines and controls the access to IMS databases. It is made up of one or more PCBs (Program Communication Block), each of which controls the access to an individual database.

In FM/IMS you can use pre-built PSBs, known as Static PSBs, or you can allow FM/IMS to generate the PSBs for you, known as Dynamic PSBs.

Static PSBs are usually developed by a Database Administrator and contain strict rules for access and control. Typically, they are used when connecting to a live or production environment. When using Static PSBs, FM/IMS uses the existing PSB load library member that you specify. If the PSB contains more than one PCB, then you can select the PCB you want to use.

Dynamic PSBs are generated by FM/IMS, using the information found in the DBD that you have specified. Dynamic PSBs generally allow full access to all the segments listed in the DBD and are, therefore, suitable for testing or development environments, but are often have restricted use in production environments. They can only be used when your FM/IMS system administrator has set up FM/IMS to allow their use. When using Dynamic PSBs, you can choose to access the database using a secondary index (if any are defined).