VSAM Interview questions 1-10

• Q1: VSAM full form?
  • Answer : Full form of VSAM is Virtual Storage Access Method
  Q2: What are the types of VSAM datasets?
  • Answer : Entry Sequenced Datasets (ESDS), Key Sequenced Datasets (KSDS) and Relative Record Dataset (RRDS).
  Q3: What is a CI, control interval?
  • Answer : A control interval is the unit of information that VSAM transfers between virtual and auxiliary storage.
  Q4: What is a CA, control area?
  • Answer : A group of control intervals makes up a control area.
  Q5: What is a cluster?
  • Answer : A cluster is the combination of the index, sequence set and data portions of the dataset. The operating system gives program access to the cluster, ie. to all parts of the dataset simultaneously.
  Q6: What is the catalog?
  • Answer : The catalog contains the names of all datasets, VSAM and non-VSAM. It is used to access these datasets.
  Q7: What is a VSAM split?
  • Answer : If there isn't enough space in the control interval VSAM performs a control interval split by moving some records to the free control intervals. If there isn't a free control interval VSAM performs a control area split by allocating a new control area and moving half of the control intervals to it.
  Q8: What is the base cluster?
  • Answer : The base cluster consists of the data component and the index component for the primary index of a KSDS.
  Q9: In the COBOL SELECT statement what is the ORGANIZATION for a KSDS?
  • Answer : The ORGANIZATION is INDEXED.
  Q10: What is the COBOL RECORD KEY clause?
  • Answer : The RECORD KEY in the SELECT clause identifies the files primary key as it will be known to the program.