CICS Interview Questions

41. Explain Execution Interface Block.
EIB is a CICS area that contains information related to the current task, which can be used for debugging the program. The most widely used variables are EIBDATE, EIBTIME, EIBAID, EIBCALEN, EIBCPOSN, EIBRESP, EIBRSRCE (resource), EIBFN (recent CICS command code), EIBTRMID and EIBTRNID.

42. Explain the notion of Logical levels and Describe the effects of RETURN, XCTL and LINK commands.
The CICS Terminal control is at the highest level and is considered to be running at logical level 0. The first Task initiated by entering a Trans-id is considered to be logical level 1, as this is first program stored in the main storage. If a ProgramA from level one calls another ProgramB using a LINK command, the ProgramB is said to be in logical level 2 as both ProgramA and ProgramB are stored in main storage. However if ProgramC is called by using the XCTL command from ProgramA, then ProgramC is said to be logical level 1, as the ProgramA is removed from the main storage after loading ProgramC. The options used with LINK and XCTL commands are PROGRAM, COMMAREA and LENGTH. RETURN command is used to pass control from one logical level to the one above it. A RETURN command at level 1 can have the options TRANSID, COMMAREA, and LENGTH, to initiate a new transaction, once the control is passed to the CICS. The RETURN command at all the other logical levels should be issued with no options.

43. How do you handle the '_' usually set by Initialize option of field macro, after the Receive Map command.
By the COBOL II Inspect verb as: INSPECT <FieldI> REPLACING ALL '_' BY SPACE.

44. What is purpose of ASSIGN command, explain in brief.
ASSIGN command can be used to determine which extended attributes are supported by the terminal. IBM manual documents more than 60 options. The most commonly used options are COLOR(data-area), HILIGHT(data-area), SCRNHT(data-area) for screen height, and SCRNWD(data-area) for screen width. The system returns the one-byte field(data-area), set to High-Value (X'FF') if the terminal supports and a low-value, if not or else the length indicating the screen height or width, based on the option used.

45. What are the important tables used in the CICS-DB2 environment.
CICS manages it's communication with DB2 with special interface modules called CICS/DB2 Attachment Facility. When a CICS program issues a SQL statement, CICS requests the attachment facility to establish a connection with DB2 called a thread. The information about the CICS transaction and DB2 is entered in Resource Control Table (RCT). The plan information is referenced through the RCT Entries.

46. What is Deadlock.
A Dead lock is a situation that occurs when two tasks are waiting for a resource that the other is holding. UNLOCK can be used to release the lock created by using the UPDATE option, when it is no more needed to be updated.

47. What types of Files can be used by CICS. Why?
VSAM, ISAM, and BDAM files on disk can be accessed by CICS, as they are all of random access type.

48. What are the various commands used to browse through a dataset?
STARTBR, READNEXT, READPREV and RESETBR. The options used are DATASET, RIDFLD, RRN/RBA, GENERIC, and KEYLENGTH for the 3 commands, and INTO, LENGTH for READNEXT and READPREV command, and EQUAL/GTEQ for STARTBR only. RESP can be used with any. ENDBR is used to end the browse operation.

49. Do you have to Handle condition every time to check the status during file handling.
No. HANDLE CONDITION is to be coded only at the beginning of the program before the first read command. If you need to change the Handle condition after a few reads or write, use PUSH and POP commands accordingly. If needed a few conditions also can be ignored by using the IGNORE CONDITION command coded before the File handling commands. If Ignore Condition is used, EIBRCODE can be used to check the return condition if needed.

50. What are the possible exceptions occurs during the file browsing process.

51. Explain Mass insert and GENERIC keywords.
The MASSINSERT option is used along with the WRITE command, to inform the system to write a bunch of inter-related records at a time. In order to decrease the I/O s with a better utilization of the VSAM CI 's. The GENERIC option is used on file handling commands, when the length of key field is a subset of the whole key along with the LENGTHKEY option.

52. Can you issue SQL COMMIT from a CICS program?

53. What is the other way of terminating a transaction?
EXEC CICS SYNCPOINT. Assuming it is a LUW. This will not end the transaction.

54. What is an ASRA abend ?
Any data exception problem SOC7, SOC4 etc.

55. What is an AEY9 abend ?
DB2/IDMS Database is not up.

56. What are the situations under which NEWCOPY is required ?
When a program has been used in CICS atleast once and then changed and recompiled.

57. What is 2 phase commit? Confirm the answer.
It occurs when a programmer Issue's an Exec CICS Syncpoint command. This is called a two phase Commit because CICS will first commit changes to the resources under its control like VSAM files, before DB2 changes are committed. Usually CICS signals DB2 to complete the next phase and release all the locks.

58. What is an AICA abend?
Runaway Task.

59. How would you resolve an ASRA abend?
In COBOL II start with CEBR, and get the offset/instruction.

60. How do you rollback data written to an ESDS file?
Define the file as recoverable. in cases where records have been inserted into the file, you may need to run a batch program to logically delete the inserted records.

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