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Q61) During processing of a VSAM file, some system error occurs and it is subsequently unusable . What do you do ?
Q61) Run VERIFY.(文章来源：http://www.newcoin.info)

Q62) How do you fix the problem associated with VSAM out of space condition?
Q62) Define new VSAM dataset allocated with more space.
Use IDCAMS to REPRO the old VSAM file to new VSAM dataset.
Use IDCAMS to ALTER / rename the old VSAM dataset or se IDCAMS to DELETE the old VSAM dataset.
Use IDCAMS to ALTER / rename the new VSAM dataset to the name of the original VSAM dataset.

Q63) What is the meaning of VSAM RETURN-CODE 28?
Q63) Out of space condition is raised.

Q64) On which datasets You can have ALT INDEX?.
Q64) only on KSDS and ESDS – not RRDS

Q65) How many Alternate Indexes you can have on a dataset?
Q65) 255 – but you must be a nut to have so many ALT Indexes on a dataset!

Q66) Is it slower if you access a record through ALT INDEX as compared to Primary INDEX?
Q66) Yes. Why? Because the alternate key would first locate the primary key, which in turn locates the actual record. Needs twice the number of I/Os.

Q67) What is RECOVERY and SPEED parameters in DEFINE CLUSTER command?
Q67) RECOVERY (default) and SPEED are mutually exclusive. Recovery preformats the control areas during the initial dataset load, if the job fails, you can restart but you must have a recovery routine already written to restart the job. SPEED does not preformat the CAs. It is recommended that you specify SPEED to speed up your initial data load.

Q68) Describe SHAREOPTIONS parameter (SHR) in Define Cluster command.
Q68) It defines the cross-region and cross-system sharing capabilities of the dataset. Syntax is SHR(Crvalue, CSvalue) value 1 means multiple read OR single write (read integrity) 2 means multiple read AND single write (Write integrity) 3 means Multiple read AND multiple write 4 is same as 3, which refreshes the buffer with every random access. default is SHR(1 3).

Q69) What does the KEYRANGES parameter in Define Cluster commend do?
A69) It divides a large dataset into several volumes according to the Key ranges specified. e.g., KEYRANGES ((0000001 2999999) (3000000 5999999)). if the activity on the key ranges are evenly distributed, concurrent access is possible, which is a performance improvement.

Q70) What are the optional parameters to the input dataset While loading the empty cluster with the data records?
A70) 1)FROMADDRESS(address) 2)TOADDRESS(address) where ‘address’ specifies the RBA value of the key of the input record. 3)FROMNUMBER(rrn) 4)TONUMBER(rrn) where ‘rrn’ specifies the relative record number of the RRDS record 5)FROMKEY(key) 6)TOKEY(key) where ‘key’ specifies the key of the input record 7)SKIP(number) 8)COUNT(number) where ‘number’ specifies the number of records to skip or copy Ex: REPRO INFILE(DD1) OUTFILE(DD2) SKIP(9000) COUNT(700) – Skips the first 9000 records and begins copying at 9001 and copies 700 records from DD1 to DD2.

Q71) What is IDCAMS? and what is the purpose of it?.
A71) IDCAMS is an access method services utility used for creating, deleting, altering VSAM files and copying sequential file to a VSAM file, etc.

Q72) How to delete a member using JCL.
A72) Using IDCAMS a member can be deleted. DELETE ‘XXX.YYY(member)

Q73) What is the Difference between LDS & ESDS ?
A73) These two datasets are VSAM datasets. ESDS maintains control information. But LDS does not maintains the control information.

Q74) Is a delete operation possible in an ESDS?B. Is rewrite operation possible in ESDS ?
A74) No delete operation is not possible in VSAM ESDS.B. Yes rewrite operation is possible in an ESDS.

Q75) What is an alternate index and path ?
A75) An alternate index is an another way of accessing key sequenced data record stored in a base cluster and path is the linkage which connect alternate index to its base cluster.

Q76) How many buffers are allotted to VSAM KSDS and ESDS?
A76) 2 data buffers by default for ESDS. For KSDS it allots 2 data buffers and 1 index buffers. each buffer is about 4k.

Q77) what’s the biggest disadvantage of using a VSAM dataset?
A77) FREE SPACE(FPSC)(文章来源：http://www.newcoin.info)

Q78) what’s the device independent method to indicate where a Record is Stored?
A78) By USING RBA(Relative Byte Address).

Q79) How many times secondary space allocated?
A79) 122 TIMES

Q80) what is the RRN for the first record in RRDS?
A80) The answer is : 1

Q81) what is a Base Cluster?
A81) The Index and data components of a KSDS

Q82) If FSPC(100 100) is specified does it mean that both the control interval and control area will be left empty because 100 % of both CI and ca are specified to be empty?
A82) No, they would not be left empty. one record will be written in each CI and 1 CI will be written for each ca.