IBM Mainframe Forum Index
 
Log In
 
IBM Mainframe Forum Index Mainframe: Search IBM Mainframe Forum: FAQ Register
 

What is the max block size


IBM Mainframe Forums -> JCL & VSAM
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
rambabu
Currently Banned

New User


Joined: 18 Apr 2005
Posts: 67

PostPosted: Mon May 09, 2005 4:52 pm
Reply with quote

what is the max block size?
Back to top
View user's profile Send private message
superk

Global Moderator


Joined: 26 Apr 2004
Posts: 4652
Location: Raleigh, NC, USA

PostPosted: Mon May 09, 2005 6:16 pm
Reply with quote

rambabu wrote:
what is the max block size?

Of what?
Back to top
View user's profile Send private message
Rajen

New User


Joined: 05 May 2005
Posts: 61

PostPosted: Mon May 09, 2005 6:55 pm
Reply with quote

i think it is 32760
Thanks
Raj
Back to top
View user's profile Send private message
anil_koneti

New User


Joined: 21 Apr 2005
Posts: 5

PostPosted: Sat May 14, 2005 11:25 am
Reply with quote

yes my friend
rajen is correct
Back to top
View user's profile Send private message
grepusr3

New User


Joined: 10 May 2005
Posts: 29

PostPosted: Sun May 15, 2005 7:00 pm
Reply with quote

Maximum allocated blocksize depends on your DASD devices, disk geometry and your record length. The allocation is based on CKD devices. Most modern DASD (Fixed Block Architecture) emulates CKD models. For optimum allocation, try coding BLKSIZE=0 in the DCB when creating your dataset (the system will define the block size for you).

Using BLKSIZE=32760 on a 3390-3 DASD may create a mucho wasted space, since it is not a whole multiple of track size. Try to allocate block size that is when multiplied (factored), it is as close to the Track Size (56,664) as possible.

For BLKZISE=32760, unallocated space per track = (56,664 - 32,760) = 23,904 bytes

Code:

                  3390 DASD/Disk Information

DASD Model____________ |__3390-2 |____3390-3 |____3390-9 |____3390-27

Track Size in Bytes___ |__56,664 |____56,664 |____56,664 |_____56,664
Tracks per Cylinder___ |______15 |________15 |________15 |_________15
Tracks per Volume_____ |__33,390 |____50,085 |___150,255 |____450,765
Cylinders per Volume__ |___2,226 |_____3,339 |____10,017 |_____30,051
Bytes per Cylinder____ |_849,960 |___849,960 |___849,960 |____849,960
Bytes per Volume______ |_1.89_GB |___2.84_GB |___8.51_GB |___25.53_GB



-Pelad
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic View Bookmarks
All times are GMT + 6 Hours
Forum Index -> JCL & VSAM

 


Similar Topics
Topic Forum Replies
No new posts Using Java/C/C++ to retrieve dataset ... Java & MQSeries 6
No new posts Find the size of a PS file before rea... COBOL Programming 13
No new posts Masking variable size field - min 10 ... DFSORT/ICETOOL 4
No new posts I need a 4 lines block where substrin... DFSORT/ICETOOL 12
No new posts Dataset size increase on adding 1 byt... DFSORT/ICETOOL 8
Search our Forums:

Back to Top