________________________________________________________________________ 
   | Table 16. GDDM data-set characteristics for IMS                        |
   |_________ __________ _________________ _________________________________|
   |         |          |                 | DCB characteristics             |
   | Type of | GDDM     |                 |________ ________ _______________|
   | Data    | default  | Data set type   | Record | Record | Block size    |
   |         | filename |                 | format | length | (BLKSIZE)     |
   |         |          |                 | (RECFM)| (LRECL)|               |
   |_________|__________|_________________|________|________|_______________|
   | Symbol  |          | Sequential data | VA     | >= 125 | LRECL         |
   | sets    | ADMTRACE | sets or SYSOUT  |________|________|_______________|
   |         |          | classes         | VBA    | >= 125 | >= LRECL + 4  |
   |_________|__________|_________________|________|________|_______________|

• One TP PCB for each concurrently active device (for example, for which a DSOPEN call was issued).
  For family-1 and family-3 (3270-family and system printer) devices, the LTERM quoted in the PCB statement must be that of the terminal to which the output is to be sent. For family-2 devices, the NAME parameter should specify the transaction code assigned to the GDDM print utility.
  If the NAME or LTERM parameter is not supplied on the PCB statement, the PCB should be defined as modifiable and the application program should issue a CHNG call to set the destination before defining the PCB to GDDM.

• A DB PCB for the system definition database if GDDM output is to be generated. A PROCOPT of G should be specified because no normal GDDM operation can alter information in this database. For multiple IMS sessions, however, a procopt of GO is recommended so that segment locking is avoided.
  A sample PCB statement for such a database is:

  
           PCB    TYPE=DB,NAME=ADMSYSDF,PROCOPT=G,KEYLEN=8
           SENSEG NAME=ADMSDSGM,PARENT=0
  
  

  Ensure that the names used in the above sample are not altered during the initialization process. If they are changed, corresponding changes must be made in the IMSSDBD and IMSSEGS options in GDDM's external defaults, described in the GDDM Base Application Programming Reference book.

• A DB PCB for each object database required.
  A sample PCB statement for such a database is:

  
           PCB    TYPE=DB,NAME=ADMOBJ1,PROCOPT=G,KEYLEN=20
           SENSEG NAME=ADMOBROO,PARENT=0
           SENSEG NAME=ADMOBDEP,PARENT=ADMOBROO
  
  

  A PROCOPT of A should be specified if the program is to alter information in the database using GDDM calls. Note the restriction that information is written only to the first of the databases quoted in the ESLIB parameter list for any given type of object.
  It is possible to vary the DBD and segment names from those quoted above during IMS system generation. If they are changed, corresponding changes must be made in the OBJFILE and IMSSEGS options in GDDM's external defaults, as described in the GDDM Base Application Programming Reference book.
  However, if only the data-base name is to be altered, the ESLIB statement can be used to notify GDDM of the data-base name rather than altering the external defaults. The name in the external defaults is only used to find the database to search for objects if no ESLIB statement is coded.