I am just giving my stack on VSAM, since VSAm is extensively being used in CICS. It is popular access method. All database DB2/IMSDB underlying datasets are still VSAM.
Q1) Difference between KSDS and ESDS- KSDS record can be accessed by primary key. ESDS record can be accessed randomly with displacement address(RBA)
Q2) AMS stands for access method services. It is used to create and maintain datasets
Q3) SHAREOPTIONS- It states how the file will be shared between jobs, batch and CICS
Q4)//Trans DD Dummy, AMP=’AMORG’- This refers to vsam dataset
Q5) DD name for ESDS must be prefixed with “AS-”
//AS-TRANS DD DSN=xyz
Q6) ESDS extensively used in online CICS. Since CICS can get access to record through “RBA”
Q7) ESDS can not be used as GDG.
Q8) Indexed- KSDS, Nonindexed-ESDS, Numbered-RRDS. Out of these “Indexed ” is default parameter.
Q9) CA/CI level spilts causes performance degradation. If splits are more it causes more I/O, and reduce the performance.
Q10) Verify command close the file correctly. Sample code
//SYSIN DD *
PRINT INDATASET(SYS1.VVDS.V339000) DUMP
ALTER DFP1.JIMONE.KSDS.DATA UNINHIBIT
ALTER DFP1.JIMONE.KSDS.INDEX UNINHIBIT
LISTC ENT(DFP1.JIMONE.KSDS) ALL
Bye wait for my next stack on VSAM.