File Handling in COBOL

      1.      How do you reference the following file formats from COBOL programs: Fixed Block File   - Use ORGANISATION IS SEQUENTIAL. Use...

     1.     How do you reference the following file formats from COBOL programs:

Fixed Block File  - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F, BLOCK CONTAINS 0 .

Fixed Unblocked - Use ORGANISATION IS SEQUENTIAL. Use RECORDING   MODE IS F, do not use BLOCK CONTAINS

Variable Block File - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS V, BLOCK CONTAINS 0. Do not code the 4 bytes for record length in FD i.e. JCL REC length will be max rec. length in pgm + 4

Variable Unblocked - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS V, do not use BLOCK CONTAINS. Do not code 4 bytes for record length in FD i.e. JCL rec length will be max rec length in pgm + 4.

ESDS VSAM file - Use ORGANISATION IS SEQUENTIAL.

KSDS VSAM file - Use ORGANISATION IS INDEXED, RECORD KEY IS, ALTERNATE RECORD KEY IS

RRDS File - Use ORGANISATION IS RELATIVE, RELATIVE KEY IS

Printer File - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F, BLOCK CONTAINS 0. (Use RECFM=FBA in JCL DCB).

     2.     What are different file OPEN modes available in COBOL?

INPUT,

OUTPUT,

I-O,

EXTEND.

     3.     What is the mode in which you will OPEN a file for writing? -

OUTPUT, EXTEND

     4.     In the JCL, how do you define the files referred to in a subroutine ?

Supply the DD cards just as you would for files referred to in the main program.

     5.     Can you REWRITE a record in an ESDS file?  Can you DELETE a record from it?

Can rewrite(record length must be same), but not delete.

     6.     What is file status 92? -

Logic error. e.g., a file is opened for input and an attempt is made to write to it.

     7.     What is file status 39 ?

Mismatch in LRECL or BLOCKSIZE or RECFM between your COBOL pgm & the JCL (or the Dataset label). You will get file status 39 on an OPEN.