|
View previous topic :: View next topic
|
| Author |
Message |
dharmendra_kp
New User
Joined: 10 Mar 2005
Posts: 33
Location: Lewiston
|
|
|
|
Hi all,
how do you calculate optimum block size for a given LRECL? This parameter plays an important role for an input or output file for production environment.
Please share the knowledge with the forum.
Thanks & Regards. |
|
| Back to top |
|
 |
William Thompson
Global Moderator
Joined: 18 Nov 2006
Posts: 3156
Location: Tucson AZ
|
|
|
|
Find the largest blksize that one or two blocks will fit on a track and is a multiple of the record size.
Or lst the system take of it for you with a blksize=0 (SDB i think?) |
|
| Back to top |
|
|
UmeySan
Active Member
Joined: 22 Aug 2006
Posts: 771
Location: Germany
|
|
|
|
Hi !
First of all it depends of the modell-numer of your installed disks.
Try TSO 3.2 and enter the attibutes of your desired file without
BLKSIZE. Press enter. Then have a look at at the cataloged file for
the blksize. Use this size in your jcl.
Regards, UmeySan |
|
| Back to top |
|
|
dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix
|
|
|
|
Hello,
Also, you can specify BLKSIZE=0 in your jcl and most sites generate an appropriate blkzise. |
|
| Back to top |
|
|
mmwife
Super Moderator
Joined: 30 May 2003
Posts: 1592
|
|
|
|
If full SMS is active in your shop you don't have to specify a blksize.
It's best to let the sys do it (SMS or blksize=0) because when there's a DASD conversion at your shop the next file created w/the JCL will posess an optimum blksize for that device type. |
|
| Back to top |
|
|
|
|
