TCS Mainframe Developer Interview Questions and Answers

COBOL has different levels such as level 01, level 77, etc. for defining data structures and variables.

• Level 01 is used for defining record structures.

• Level 77 is used for defining elementary data items.

• Level 88 is used for defining condition names.

• Level 66 is used for renaming data items.

• Level 88 is used for defining condition names.

Rename is used to change the name of a data item while redefine is used to change the structure of a data item.

• Rename is used to change the name of a data item without changing its structure

• Redefine is used to change the structure of a data item without changing its name

• Example: In COBOL, renaming a data item involves using the RENAMES clause, while redefining a data item involves using the REDEFINES clause

IDCAMS utility is used for creating GDG (Generation Data Group)

• IDCAMS utility is used to define, alter, and delete GDGs

• Syntax for defining GDG: DEFINE GDG(NAME(dataset.name) LIMIT(n) SCRATCH)

• Example: DEFINE GDG(NAME(TEST.GDG) LIMIT(5) SCRATCH)

GDG (Generation Data Group) version and its attributes are used in mainframe development to manage versions of datasets.

• GDG is used to manage versions of datasets in mainframe environment.

• Attributes of GDG include generation number, creation date, expiration date, and limit.

• Example: MYDATASET.GDG(+1) refers to the latest version of MYDATASET.

Static call is resolved at compile time, while dynamic call is resolved at runtime.

• Static call is determined at compile time based on the declared type of the object.

• Dynamic call is determined at runtime based on the actual type of the object.

• Static call is faster but less flexible, while dynamic call is slower but more flexible.

The SORT command in Mainframe can be used to search for a string.

• Use the SORT command with the FIND keyword followed by the string you want to search for.

• Specify the input file and output file for the search operation.

• Example: SORT FILE(INPUT) USING(CTL1) COPY FIND FIRST 'SEARCHSTRING' OUTPUT FILE(OUTPUT)

Mainframe modernization process involves updating legacy systems to newer technologies while preserving critical business logic.

• Assess current mainframe environment and identify areas for modernization

• Develop a modernization strategy, including choosing the right technology stack

• Migrate data and applications to the new platform while ensuring minimal disruption to business operations

• Test the modernized system thoroughl...read more

Temporary files in JCL are used to store intermediate data during job execution.

• Temporary files are defined using DD statements in JCL.

• They are typically used to store data that needs to be processed or manipulated before being written to permanent files.

• Temporary files are often allocated with DISP=(MOD,DELETE) to ensure they are deleted after job completion.

Sort JCL utilities are used to sort data in Mainframe environment based on specific criteria.

• Use SORT utility in JCL to sort data in ascending or descending order

• Specify the key fields to sort on in the SORT statement

• Use INCLUDE and OMIT statements to filter data before sorting

• Use JOINKEYS utility to merge two or more sorted datasets based on key fields