What is DBD database?
A database description (DBD) is a DL/I control block containing all of the database information needed by an application program. You create a database description (DBD) by coding special macro instructions. These macros become the input to the DBDGEN utility.
What is DBD in IMS DB?
Database Descriptor (DBD) DBD describes the complete physical structure of the database once all the segments have been defined. While installing a DL/I database, one DBD must be created as it is required to access the IMS database.
What is PSB and DBD in IMS?
When the IMS™ catalog is used, it stores metadata about data types, data structures, access methods, and much more. This metadata is derived from the database descriptors (DBDs) and program specification blocks (PSBs) that you create when you define your databases and application programs views to IMS.
How many DBDs can be there for a single database?
For a shared secondary index database, the names of up to 16 secondary index DBDs can be specified. A numeric value from 1 to 2147483647 that identifies a specific version of a DBD when multiple DBDs are used by application programs to access the same database.
What is PCB and PSB?
A PSB consists of one or more program communication blocks (PCBs). Whenever an application program needs to access a new segment on an existing database or whenever it needs to access a new database, the PSB must be altered. Whenever the PCB modified, which are all PSBs using the PCB should be altered.
What is PSB JCL?
The Program Specification Block (PSB) Generation utility generates PSBs from macro instructions that describe the characteristics of application programs and the use of logical terminals and logical data structures. The PSB Generation utility is required before you can run an application program under IMS™.
What is PCB mask in IMS DB?
IMS DB – PCB MASK. PCB stands for Program Communication Block. PCB Mask is the second parameter used in the DL/I call. It is declared in the linkage section.
What is ACB IMS?
An ACB is the run-time control block which is a consolidation of PSBs and DBDs. In another words, Application control blocks (ACBs) are created by merging information from PSBs and DBDs. For online program ACB must be build before using ACB maintenance utility.
Is used to define PSB?
Program Specification Block defines the programs view of the database and application Programs access authority to database. PSB defines the logical data structure. PSB is made up of one or more PCBs (Program communication blocks). PSB describes the database as a particular application program views it.
What is a PCB IBM?
Printed Circuit Board (PCB) design | IBM.
What is mainframe PCB?
PCB used to defines the application view of the database. The PCB (Program Control Block) is the program’s view of database. PCB Mask is the parameter used in the DL/I call.
What is PCB in Imsdb?
PCB stands for Program Communication Block. PCB Mask is the second parameter used in the DL/I call. It is declared in the linkage section.