What is the difference between CI( CONTROL INTERVAL)and CA(CONTROL AREA). I refereed SAB A ZAMIR JCL book in that he said collection of CI is called CA but in next page (286) he explained this with showing one CI as a CA. Can you please let me know the difference?

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Showing Answers 1 - 17 of 17 Answers

prasad yadav J

  • Apr 24th, 2006
 

hi,

control area is group of CI's ,that may be 1 CI or more than one CI,

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Javid

  • May 2nd, 2006
 

cONTROL INTERVAL :- It is same as Blocks are in JCL. It is the storage unit.

Control Area : - It is collection of CI.

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Vijay

  • May 9th, 2006
 

CI is a memory stored in blocks, but CA is a collection of CI's.

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Pradeep Bhatt

  • May 29th, 2006
 

Hi dear,

   CI(Control Interval) is the smallest unit of memory in vsam collection of which is called a Control Area(CA). A CI is equivalent to the record block for normal sequential file. CI can contain many records. A record can vary from one CI to another within a CA.

Can anybody explain the concept of CI split and CA split.

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Naren

  • Jun 30th, 2006
 

C.I is the unit of memory transferred between secondary memory and primary memory., which is equivalent to block in QSAM.

[ this information is not related to the question., i am just giving this to Know C.I better

size of C.I should be between 512b and 32768b., and it should be multiple of 512b]

Where as C.A is collection of two or more control intervals.

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Mohamed Maideen

  • Dec 29th, 2006
 

Hi

The CI is a single unit of transfer from secondary to main memory. Inside it will have freespace to store the records of fixed or variable size.

If u try to insert a new record to a ci which is not having any space to hold at that time the half of the record from this ci will be moved to some free ci. This splitting of ic in case of ci full is called CI splitt.

A collection of ci is called as CA. During the ci splitt if it is unable to find the free ci at that time the entire CA will be splitted into two and half will be moved to some free CA. This is called CA splitt. This is the primary mechanism of the VASM to store all the records inside your ksds in sorted order.

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lokesh heda

  • Jul 8th, 2007
 

ci is a unit which contains information which is pass/transfer between virtual storage and auxilary storage.
while ca is nothing but combination of two or more ci. 

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venkat.palla

  • Aug 7th, 2007
 

CI and CA in VSAM are the acronyms for Control Interval and Control Area respectively. Basically CI is the area within which group of records are stored. Collection of CIs are stored in CA. CIs will take part in Input-Output operations of Data. Apart from CIs, CAs will also consists of Sequence Sets - which are part of Index. These Sequence Sets will have pointers to every CI, based on highest key size. CIs are consisting of Data Area, Unused Area, Free Area, CIDF and 2 or multiples of 2 number of RDFs. Both CIs and CAs have some percentage of free space for KSDS files. The process of Split and Span are applicable for CI and CAs.

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rb333

  • Apr 15th, 2009
 

Both the statements are true. Collection of CI's is called CA means one or more than one CI together forms a CA. In case, a CA comprises of only one CI it means CI=CA in that case. Hope i answer your question.

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