Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
What does Imbed option do while defining a KSDS

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DFSORT/ICETOOL
View previous topic :: :: View next topic  
Author Message
Madhu Kashyap

New User


Joined: 19 Jan 2006
Posts: 19

PostPosted: Thu Jan 19, 2006 2:30 pm    Post subject: What does Imbed option do while defining a KSDS
Reply with quote

Hi ,

Can anyone please tell me what does Imbed option do while defining a KSDS?
Back to top
View user's profile Send private message

senthils

Active User


Joined: 15 Nov 2005
Posts: 117
Location: Chennai, India

PostPosted: Thu Jan 19, 2006 2:48 pm    Post subject:
Reply with quote

Without replicate and Imbed, data CAs and CIs can be stored in different places on the disk from the index. This means that several I/Os are required for each access.

With Imbed and noreplicate, each data CA has its sequence set record at the front of the CA. If the CASZ is 1 cylinder then the sequence set is maintained on the 1st track of the cylinder. If the CASZ is less than 1 cylinder then one track is added to the CASZ. Thus, it costs 1 track per CA as the sequence set is written around the track as often as possible. Rotational delay is reduced as the r/w arm is placed above the sequence set and data. However, index updates cause an overhead as each copy of the sequence set has to be updated. Sequential processing benefits immensely from Imbed.

With replicate and noimbed, all data CAs and indexes are separate. Each higher level index is written as often as possible on a track. This option uses a lot of extra space and also requires extra I/O for index updates. If using this option the index should be allocated in cylinders and imbed should also be used. Since sequential processing only uses the sequence set, then replicate is of no value for sequential processing.
Back to top
View user's profile Send private message
Rupesh.Kothari

Member of the Month


Joined: 27 Apr 2005
Posts: 464

PostPosted: Thu Jan 19, 2006 2:53 pm    Post subject: Re: Vsam Files
Reply with quote

HI,

Quote:
Can anyone please tell me what does Imbed option do while defining a KSDS?

I Read the following thing in one book regarding IMBED option.

This places the sequence set values in the first track, this will reduce the rotational time during access, so this is basically a performance issue.

Hope this helps

Regards
Rupesh
Back to top
View user's profile Send private message
Madhu Kashyap

New User


Joined: 19 Jan 2006
Posts: 19

PostPosted: Thu Jan 19, 2006 3:15 pm    Post subject: Re: Vsam Files
Reply with quote

Thanks for answering my query.
Back to top
View user's profile Send private message
nagendrat

New User


Joined: 18 Jan 2006
Posts: 5

PostPosted: Thu Jan 19, 2006 7:42 pm    Post subject: Re: What does Imbed option do while defining a KSDS
Reply with quote

The IMBED option places the index component's sequence set records in the space with the data component and causes the sequence set record to be duplicated as many times as possible on its track. This means that the first track of each control area will not be available for user data
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DFSORT/ICETOOL All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts ISSUE IN copying Sequential file reco... thesumitk JCL & VSAM 2 Wed Dec 13, 2017 3:07 pm
No new posts Where is output from PARM ABEXIT (SNA... packerm CA Products 3 Thu Sep 28, 2017 4:06 pm
No new posts MQ command in option 6 of ISPF! Vignesh Sid All Other Mainframe Topics 3 Tue Sep 26, 2017 6:01 pm
No new posts DFSORT - Overriding default option TU... Steve Ironmonger DFSORT/ICETOOL 3 Tue Apr 04, 2017 3:54 pm
No new posts BWO option in VSAM blayek CICS 3 Sat Nov 05, 2016 10:47 am

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us