Then during each processing cycle, the new version of the file becomes the current version. MAST( 1), DISP=(NEW, CATLG), UNIT=3300, VOL=SER=BS3001, DCB=(LRECL=80, BLKSIZE=1600)//PAYTRAN DD DSN=MMA2. TRAN, DISP=OLD//PAYLIST DD SYSOUT =*//JOB2 JOB ...........//REPORT EXEC PGM=PAY3300//PAYMAST DD DSN=MMA2. MAST(0), DISP=OLD//PAYRPT DD SYSOUT=*Example 9.3b Adding datasets to a GDGGDG’s are a group of datasets which are related to each other chronologically and functionally.Although MVS lets you use relative generation numbers to simplify cyclical processing, MVS uses “Absolute Generation Numbers” in the form Gnnnn V00 to identify each generation dataset uniquely. Generations can continue until a specified limit is reached.For information about citing data sets in publications, please read our citation policy.If you wish to donate a data set, please consult our donation policy.Two areas rise up above the rest of the surface and are referred to as " continents." The first, Ishtar Terra is located in the Northern Hemisphere and is about the size of Australia.The highest point on Venus, the mountain Maxwell Montes is located on Ishtar Terra.
When you create a generation data group’s catalog entry, you specify how many generations should be maintained Example: You might specify that five generations including the current generation should be maintained.
The new version becomes the current generation; it replaces the old current generation, which becomes a previous c1( 1) Next Generationfile.c1(0) Current Generationfile.c1(-1) Previous Generationsfile.c1(-2)file.c1(-3)Figure above is the structure of a generation data group.
There are 3 previous generations, note that generations are numbered relative to the current generation, file.c1(0).
Relative generation numbers are adjusted when each processing cycle completes, so that the current generation is always referred to as relative generation 0.
MVS uses the generation data group’s catalog entry to keep track of relative generation numbers.
Although there are many different uses for sequential datasets, many sequential files have one characteristics in common : they are used in cyclical application for example, sequential dataset that contains transaction posted daily against a master file is cyclical; each days transactions, along with the processing required to post them, from one cycle.