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VSAM interview Questions

 
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THINKSRINIII
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PostPosted: Tue Mar 31, 2009 12:29 pm    Post subject: VSAM interview Questions
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Hi,

Can someone please help me with these questions?

VSAM Interview Questions.

1.The record keys in a CI are 100,200 and 300. The CI is full and there is no free space allocated.What will happen when key 250 is added to the dataset?

a.Record 300 will be moved to a new CI, and record 250 will be placed in the place where 300 was.
b.Record 200 will be moved to a new CI. Record 300 will be moved to the new CI, leaving space for record 250. It will be placed between records 200 and 300.

2.VSAM internal security may be applied to which of the following levels?

a.Path, cluster, I
b.Read,update,CI,Master
c.Delete,update,write,Master

3.What is meant by FREESPACE(10,15)
A.That 10% of the CI’s per CA and 15% of each CI will be reserved.
B.That 10% of each CI and 15% of the CI’s in each CA will be reserved.

4.Control Area #1 has all of its free space expended. CA#2 is unused. The allocation is FREESIZE(25 25).,And the processing method is direct access.
What happens when the next CI split occurs?
A.The last half of the CI’s from CA1 are moved to first half of CA2
B.The new CI is inserted into CA2
C.The last CI from CA1 is moved to CA2, and the new CI is inserted into the slot created.
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THINKSRINIII
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PostPosted: Tue Mar 31, 2009 12:40 pm    Post subject:
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Apologise.. Missed my Options.. Just want to confirm with you guys..

1. a
2. c
3. b
4. b
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Robert Sample

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PostPosted: Tue Mar 31, 2009 5:04 pm    Post subject:
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From the VSAM Demystified Redbook (SG24-6105):
Quote:
If a record is to be inserted (in key sequence) and there is not enough free space in the CI, the CI is split. Approximately half of the records in the CI are transferred to a free CI provided in the CA, and the record to be inserted is placed in the original CI.
If there are no free CIs in the CA and a record is to be inserted, a CA split occurs. Half of the CIs are sent to the first available CA at end of the data component. This movement creates free CIs in the original CA, then the record to be inserted causes a CI split.
Based on this, I would say the answer to #1 is a - the record is inserted in the original CI. I don't know about #2 -- c makes sense but I've never researched it. #3 is b. #4 is a, based on the quote and assuming there's only 2 CA in the file; if there are more then none of the answers would apply.
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THINKSRINIII
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PostPosted: Wed Apr 01, 2009 9:06 am    Post subject:
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Thanks a lot Rob.
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THINKSRINIII
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PostPosted: Wed Apr 01, 2009 10:38 am    Post subject:
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Hi Rob,

Just a query on Question 1. As there are 3 records (100,200,300).
Quote:

If a record is to be inserted (in key sequence) and there is not enough free space in the CI, the CI is split. Approximately half of the records in the CI are transferred to a free CI provided in the CA, and the record to be inserted is placed in the original CI.


It says half the Number of records. If its even number of records. I can understand.. Could you explain how only 300 is moved to the new CI in this case.
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Robert Sample

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PostPosted: Wed Apr 01, 2009 4:41 pm    Post subject:
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If there are 3 records in the Ci, approximately half could be 2 records or 1 record. However, the quote also states that the inserted record goes into the original CI, so only the 1 (300) record would be moved.
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THINKSRINIII
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PostPosted: Wed Apr 01, 2009 4:45 pm    Post subject:
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Thanks a lot Rob.
You have hit the nail on the head. icon_biggrin.gif
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THINKSRINIII
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PostPosted: Thu Apr 02, 2009 3:37 pm    Post subject: VSAM Interview Questions2
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Hi Guys,

Could some one help me in getting the answers for these.

1. What happens when an VSAM dataset is opened for an update. IS the entire CI is locked containg the record to be updated is locked or only that particular record.

2. What is the Maximum number of A.I's a ESDS can have? A KSDS

3. What is the difference between SHAREOPTIONS(3 3),SHAREOPTINS(3 4),SHAREOPTIONS(4 3),SHAREOPTIONS(4 4)
( I have had a look at the manual and can see the Difference between other share options but this is not crisp).

Thanks in Advance
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enrico-sorichetti

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PostPosted: Thu Apr 02, 2009 3:45 pm    Post subject: Reply to: VSAM Interview Questions2
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1) none as far as VSAM itself is concerned

2) read the manual
( certainly the limit will be higher than your need, if not so You have a case of bad application design)

3) SHAREOPT(x y) the x and y are independent
so it is enough to read the two paragraphs independently from each other
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dbzTHEdinosauer

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PostPosted: Thu Apr 02, 2009 3:47 pm    Post subject:
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why don't you take a look at the links provided by ES in your previous post.

not many of us have an interest in helping you avoid reading the manuals.

especially VSAM demystified - which is a redbook, easy to read, is indexed.............
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