IBM MAINFRAME HELP FORUMS for COBOL, JCL, CICS, DB2, IMS etc...

nagamanjari · 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 · Joined: 26 Sep 2005 Posts: 152 Location: Bangalore

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

Manuneedhi K · Joined: 07 May 2008 Posts: 119 Location: Chennai

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. · Joined: 22 Apr 2006 Posts: 1708 Location: Phoenix, AZ

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. · Joined: 22 Apr 2006 Posts: 1708 Location: Phoenix, AZ

Hi,
Manuneedhi K wrote: 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. Yup, they will be created but I doubt FBS & VBS are still in that frequet use.