What is the difference between BLKSIZE and LRECL?

Question Posted / guest

3 Answers
17406 Views
I also Faced
E-Mail Answers

Answers were Sorted based on User's Feedback

What is the difference between BLKSIZE and LRECL?..

Answer / guest

LRECL is the length of ur record file.
Blksize is the length of the block in which records are
stored.It varies in case of fixed length records and
variable length records.
fixed length records-It is a multiple of lrecl.
e.g. suppose u have blksize =800 & lrecl=80.It means that
there are 10 records each of size 80.
variable length records-It is the length of longest record
in the block + 8 (bcoz. here lrecl=length of longest record
+4 & blksize=lrecl+4).

Is This Answer Correct ?

13 Yes

0 No

What is the difference between BLKSIZE and LRECL?..

Answer / guest

LRECL is the logical record length , where as BLKSIZE is
multiples of LRECL

Is This Answer Correct ?

8 Yes

0 No

What is the difference between BLKSIZE and LRECL?..

Answer / stu

Data is read and written to files in blocks. The reading
and writing of blocks is I/O. I/O is overhead (increases
runtime and cost) and you want to keep it to a minimum.

When reading a file, a whole block of records will be read,
but the records in the block will be fed to the program one
at a time until the block is exhausted and the next block is
read. The operating system does this behind the
scenes--it's transparent to the programmer.

When writing to a file, the records are not actually written
to the file until a block is full (or the program ends--at
which time the last block is written if it contains at least
1 record.) Again, this is transparent to the programmer.

Obviously, to keep I/O low, you want the cram as many
records into a block as possible.

Let's say your FB file's record length (LRECL) is 252 bytes
and your facility allows block sizes up to 27000 bytes.
Your blocksize would be ((integer (27000 / 250)) * 252) or
26964 (107 records).

Is This Answer Correct ?

0 Yes

0 No

Post New Answer

More JCL Interview Questions

Hi, Say I have 10 flat files and I want to copy all these 10 flat files to a GDG versions flat files (I have GDG base: FDWS01.TEST.RESTORE) in one shot. Can we do that in one shot using a JCL. May be by using IEBGENER. It's a bit urgent. So anyone's fast rely would be appreciated.. Thanks in advance.. 10 flat files ----------------------------------- FDWS01.SUB.RESTORE1 FDWS01.SUB.RESTORE2 FDWS01.SUB.RESTORE3 ; ; FDWS01.SUB.RESTORE10 TO GDG versions ----------------------- FDWS01.TEST.RESTORE.G0001V00 FDWS01.TEST.RESTORE.G0002V00 FDWS01.TEST.RESTORE.G0003V00 ; ; FDWS01.TEST.RESTORE.G0010V00

2 Answers

We have an output dataset in job with disp parameter as SHR. Can we write data in that file dataset?

2 Answers CTS, IBM,

What is the purpose of dd * statement in jcl?

0 Answers

Can we find specific member without knowing the name of PDS or can we search a member to which PDS it belongs to? if so how?

6 Answers

Explain the job statement in jcl?

0 Answers

How to create delta file using JCL

1 Answers CTC,

What do you understand by the terms: joblib and steplib?