VSAM Interview Questions and Answers - DoAnswers.com

Virtual Storage Access Method (VSAM) is an IBM disk file storage scheme first used in the OS/VS2 operating system and later used throughout the MVS architecture. VSAM comprises four access methods: Key Sequenced Data Set (KSDS), Relative Record Data Set (RRDS), Entry Sequenced Data Set (ESDS) and Linear Data Set (LDS). See record-oriented filesystem. VSAM records can be of fixed or variable length. They are organised in fixed-size blocks called Control Intervals (CIs), and then into larger divisions called Control Areas (CAs). Control Interval sizes are measured in bytes � e.g. 4K � while Control Area sizes are measured in disk tracks or cylinders. Virtual Storage Access Method (VSAM) is an IBM disk file storage scheme first used in the OS/VS2 operating system and later used throughout the MVS architecture. VSAM comprises four access methods: Key Sequenced Data Set (KSDS), Relative Record Data Set (RRDS), Entry Sequenced Data Set (ESDS) and Linear Data Set (LDS). See record-oriented filesystem. VSAM records can be of fixed or variable length. They are organised in fixed-size blocks called Control Intervals (CIs), and then into larger divisions called Control Areas (CAs). Control Interval sizes are measured in bytes � e.g. 4K � while Control Area sizes are measured in disk tracks or cylinders. Virtual Storage Access Method (VSAM) is an IBM disk file storage scheme first used in the OS/VS2 operating system and later used throughout the MVS architecture. VSAM comprises four access methods: Key Sequenced Data Set (KSDS), Relative Record Data Set (RRDS), Entry Sequenced Data Set (ESDS) and Linear Data Set (LDS). See record-oriented filesystem. VSAM records can be of fixed or variable length. They are organised in fixed-size blocks called Control Intervals (CIs), and then into larger divisions called Control Areas (CAs). Control Interval sizes are measured in bytes � e.g. 4K � while Control Area sizes are measured in disk tracks or cylinders.

VSAM Interviews are getting tough these days as the technology grows faster. To get through the VSAM interview one needs to update him/herself in a regular manner. Having said that, just before the interview, it is very important to have a quick glance of the reputed VSAM questions and answers to make yourself comfortable during the interview process. This is where DoAnswers.com helps you in renewing yourself on VSAM and various other technologies interview preparation.

They are end of file (10), duplicate key (22), record not found (23), VSAM logic error (90), open problem (92) and space problem (93).

43. Suppose 3 generations of a GDG exist. How would you reference the 1st generation in the JCL?

44. Suppose a generation of GDG gets created in a particular step of a proc. How would you refer the current generation in a subsequent step? What would be the disposition of this generation now?

Relative generation numbers are updated only at the end of the job, not at the end of a step. To allocate a new generation, we would be using (+1) with a DISP of (NEW,CATLG,DELETE). To refer to this in a subsequent step in the same job, we would again use (+1) but with a DISP of SHR or OLD.

Note: these can be used only under IDCAMS and not from the TSO prompt. IF LASTCC(or MAXCC) >(or <,= etc..) value - THEN - DO - command set (such as DELETE, DEFINE etc..) ELSE - DO - command set LASTCC - Condition code from the last function (such as delete) executed MAXCC - Max condition code that was returned by any of the prev functions SET is also a valid AMS command. SET LASTCC (or MAXCC) = value The maximum condition code is 16. A cond code of 4 indicates a warning. A cond code of 8 is usually encountered on a DELETE of a dataset that is not present.

Note: these can be used only under IDCAMS and not from the TSO prompt. IF LASTCC(or MAXCC) >(or

47. There are at least seven IDCAMS commands; name and explain each of them ?.

ALTER modifies information for a catalog, alternate index, cluster or path. BLDINDEX builds the alternate index, of course. DEFINE is used for ALTERNATEINDEX, CLUSTER or PATH. DELETE removes the catalog entry for a catalog, cluster, alternate index or path. LISTCAT lists information about the dataset. PRINT prints the dataset contents. REPRO copies records from one file to another.

48. Under IDCAMS , multiple functions can be executed, each of which returns a cond code. What will be the condition code returned to the operating system ?

The maximum condition code generated is returned as the condition code of the IDCAMS step.

In the JCL, you must have DD stmts for the cluster and for the path(s). In the COBOL Program, SELECT .. ASSIGN TO ddname for base cluster RECORD KEY IS... ALTERNATE RECORD KEY IS..

FCT entries must be created for both base cluster & the path. To read using the alternate index, use the dd name of the path in CICS file control commands.