regarding DCB parameters in JCL

nagamanjari · New User Joined: 25 Apr 2008 Posts: 9 Location: hyderabad

Hi,
Can anyone suggest me the correct option for the following question.

Which of the following statements correctly describe DCB sub-parameter
combinations that will cause JCL or other errors?
A. DCB=(LRECL=201,RECFM=FBS,BLKSIZE=20100)
B. DCB=(LRECL=133,RECFM=VBS,BLKSIZE=13700)
C. DCB=(LRECL=80,RECFM=FB,BLKSIZE=3120)
D. DCB=(LRECL=80,RECFM=VB,BLKSIZE=84)
E. DCB=(LRECL=200,RECFM=VB,BLKSIZE=2004)

expat · Posted: Tue Jun 10, 2008 2:33 pm Post subject:

1) What do YOU think is correct and why.

2) Are there possibly more than one correct answer.

3) The coding in the example is ancient. Especially those inefficient blocksizes.

I usually code only RECFM=xx,LRECL= and let the operating system do the rest. Very rarely do I bother with the blocksize unless it is a must to code.

nuthan · Posted: Tue Jun 10, 2008 3:17 pm Post subject:

Hi,
Can you post the question correctly. Its quite confusing.

Manuneedhi K · Posted: Tue Jun 10, 2008 3:28 pm Post subject:

Just tried all the options through 3.2 and all five worked. Not sure if it creates issues when used in jcl need to try that out.

Anuj D. · Posted: Tue Jun 10, 2008 6:25 pm Post subject:

Hi,

Some points, which might help to pick up the right alternative/s -

Regardless of organization, the physical structure of each record is essentially the same, and is uniform throughout the dataset. This is specified in the DCB RECFM parameter.

- When RECFM is F or U, the length must not exceed DCB BLKSIZE. RECFM=F means that the records are of fixed length, specified via the LRECL parameter,

- For RECFM=D or V, the length must not exceed BLKSIZE minus 4 and RECFM=V specifies a variable-length record. V records when stored on media are prefixed by a Record Descriptor Word (RDW) containing the integer length of the record in bytes.

- For RECFM=VS, the length can exceed BLKSIZE.

- LRECL=0 is valid only for RECFM=U.

- With RECFM=FB and RECFM=VB, multiple logical records are grouped together into a single physical block on tape or disk. FB and VB are fixed-blocked, and variable-blocked, respectively. The BLKSIZE parameter specifies the maximum length of the block.

- RECFM=FBS could be also specified, meaning fixed-blocked standard, meaning the all blocks except the last one were required to be in full BLKSIZE length.

- RECFM=VBS, or variable-blocked spanned, means a logical record could be spanned across two or more blocks, with flags in the RDW indicating whether a record segment is continued into the next block and/or was continued from the previous one.

Anuj D. · Posted: Tue Jun 10, 2008 6:48 pm Post subject:

Hi,