HP NonStop G-Series - Manual (Page 42)

Tape File Concepts
DSM/Tape Catalog User’s Guide — 520233-008
2 - 2
File Generations
Example
Assume that every Monday an application runs that requests the latest generation of
MASTER_ACCT with this DEFINE:
90> ADD DEFINE =IN, CLASS TAPECATALOG,&

90> & USE IN,&

90> & FILEID MASTER_ACCT,&

90> & GEN -1
When running the application at the fifth week on March 2, the =IN DEFINE retrieves
generation 4 of MASTER_ACCT on tape T00155 as the input file, and the new output
file is cataloged as generation 5 on tape T00188:
Each time the application runs, it creates the output tape file MASTER_ACCT using
this DEFINE:
12> ADD DEFINE =OUT, CLASS TAPECATALOG,&

12> & USE OUT,&

12> & POOL ACCOUNTING_TAPES,&

12> & FILEID MASTER_ACCT,&

12> & GEN +1
The first time MASTER_ACCT was created and cataloged, its entry was given 1 as a
generation number. After the first month, the four tape file entries are in the catalog:
Tape File Name Tape Name Generation Creation Date
MASTER_ACCT T00045 1 February 3
MASTER_ACCT T00102 2 February 10
MASTER_ACCT T00136 3 February 17
MASTER_ACCT T00155 4 February 24
MASTER_ACCT T00188 5 March 2
Tape File Name Tape Name Generation Creation Date
MASTER_ACCT T00045 1 February 3
MASTER_ACCT T00102 2 February 10
MASTER_ACCT T00136 3 February 17
MASTER_ACCT T00155 4 February 24