IBM AS400 interview Questions and Answers

1.How are the objects stored on AS/400?

Ans: All objects are stored on AS/400 in a single level storage.

In this method all objects are referenced by one virtual address which is translated in to a physical address whether it is an auxiliary storage or main memory.

2.What is a Library in AS/400?

Ans: A library in AS/400 is an object that serve(acts) as a repository for other objects.

3.Name few IBM supplied libraries?

Ans:QGPL, QTEMP, QSYS, QUSRTOOL, QCBL, QRPG.

4.What is library list ?

Ans: A list that indicates libraries used for the process and the order in which it has to be searched System identifies it in *LIBL.

5.How many libraries can be there in library list ?

Ans:Total 40 (15 system and 25 application).

6.Describe the function of SETLL operation in RPG language?

Ans:The SETLL operation positions a file at the next record with a key or relative record number that is greater than or equal to key or relative record number specified in factor1.

7.Describe the function of SETGT operation in RPG language?

Ans:The SETGT operation positions a file at the next record with a key or relative record number that is greater than key or relative record number specified in factor 1.

8.What is the purpose of Level Check parameter in a Physical file?

Ans:Specifies whether the level identifiers of the record formats in the physical file are checked when the file is opened by the program.

9.Define a Job Queue?

Ans:Job queues are queues of batch jobs waiting to be processed.

10.Define a Output Queue?

Ans:Output queues are queues of jobs waiting to be printed.

11.What is the function of CPYSPLF command?

Ans:It copies the spooled file to the data base file.

12.What is the function of CPYF command?

Ans:To copy the data from the one file to another.

13.What is the function of CRTDUPOBJ command?

Ans:To create the replica from the original object.

14.Define Subsystem?

Ans:Subsystem is nothing but it provides specialized environment to complete the execution of jobs.

15.What are different types of Substems?

Ans:QBATCH, QINTER, QSPL, QCMN, QCTL, QBASE.

16.Define a Batch Job?

Ans:
* A user request the job.
* The job is created (job name is assigned, job attributes are allocated)
* The job is placed on a job queue
* The sub system QBATCH takes the job from job queue and starts it.
* Output generated by the batch job is placed on an output queue.
* The spool sub system prints the output on the output queue.

17.Describe about Query/400?

Ans:Query/400 is a licensed program that uses a query to analyze and select the information contained in the data base files and create a query report.

A query report can be:

* displayed on a workstation (screen)
* printed
* stored in another database file.

18.What is the CLP command to access a Query/400?

Ans:WRKQRY

19.How do you pass parameters in CL?

Ans:Using PARM keyword.

20.What are the valid user defined data area types?

Ans:CHAR, NUMERIC and LOGICAL

21.What is Multi-format logical file?

Ans:Logical which uses fields from two or more physical files.

22.What is the Select and Omit criteria in logical file?

Ans:This is used to specify rules for the Selection/Omission of records from a Physical File.

23.Can fields be concatenated in a logical file level?

Ans:Yes. by using CONCAT keyword

24.When would the ALL keyword be used?

Ans:Use with Select or Omit, to select/omit records.

25.What are the different types of keywords in display files?

Ans:File level, Record format level, Field level

26.What is difference between CAT, TCAT, BCAT?

Ans:

CAT – Concatenate two variables or constants into one continuous string.

BCAT – Truncates all trailing blanks in the first character string, one blank is inserted, then the two character strings
are concatenated.

TCAT – Truncates all trailing blanks in the first character string, the two character strings are concatenated.

27.What are the different types of messages in CL?

Ans:Immediate message, Break message, Program message, User message

28.How to trap errors in CL?

Ans:By using Monitor Message Command (MONMSG)

29.What is the maximum length of a variable name in CL?

Ans:Maximum 11 characters (including ‘&’)

30.What is the use of Header Specification in RPG/400?

Ans:It identifies by H in column 6, provides informaion about generating and running programs.

31.When will DUMP and DEBUG opcodes be ignored?

Ans:If blank is specified in position 15 of H specs.

32.Specify different indicators used in RPG?

Ans:

Overflow indicators
Record Identifying Indicators
Field Indicators
Resulting Indicators
Control Level Indicators

33.What are Control level indicators?

Ans:L1 to L9 used to identify certain fields on control fields and then used to condition which operations are to be processed at detail or total calculation or output time.

34.What is the use of E specification in RPG?

Ans:Extension Specs describes all record address files, arrays and tables.

35.What is the use of L specs in RPG?

Ans:Line counter specification can be used to describe printer file to indicate the length of the form and number of lines per page.

36.In which specification the report layout can be defined?

Ans:O Specification.

37.How many files can be defined in F specs?

Ans:50

38.How many printer files can be defined in F specs ?

Ans:8

39.A program variable coded in an Embedded SQL statement is referred to as?

Ans:Host Variable

40.Which of the CL command can be used to determine which logical files are dependent on a specific file?

Ans:DSPDBR

41.What does DFU program you to do on a record?

Ans:Insert, Update Delete & File Enquiry.

42.When are the Unique Constraints executed?

Ans:During Insert.

43.When are the Referential Constraints executed?

Ans:Insert, Update & Delete.

44.How many triggers can be associated with a file?

Ans:6(Maximum)

45.Why is the Declare cursor statement is used for?

Ans:To define & name the cursor & specify rows to be fetched.

46.What do we can do with the Embedded SQL statements?

Ans:We can Insert/Update/Delete records, fetch records, fetch values from records into variables.

47.Which CL command is used to trap error messages during program execution?

Ans:MONMSG

48.Which CL command can be used at program execution to redirect the file named in an RPG program?

Ans:OVRDBF

49.What is *ISO date format?

Ans:YYYY-MM-DD for other formats refer to IBM manual or ERIS document.

50.What are the important factors in Error message subfile ?

Ans:We must define error message record format (SFLMSG). And a Program Queue. (PGMQ) and Record format is associated to a line number.

51.How to define to define a Hidden filed in DSPF ?

Ans:Define a filed in a DSPF of use HIDDEN.(H)

52.How To get the cursor position?

Ans:With the help of RTNCSRLOC keyword, here we need to define a field to get row and column. Length of variable should be 5,0 fixed We can specify *FILED for filed *REC for Record on which a key is pressed.

53.What is OVERLAY?

Ans:It allows a record format to be displayed on screen retaining the previous displayed record formats.

54.What key word is used when screen is re-display?

Ans:RSTDSP is a parameter to be specified at compile time for display file.

55.Command Attention key and Command Function Key ?

Ans:With the help of Command attention key we can pass only the indicator status to program not the data from screen. While command function key passes indicator status as well as a data from screen to program.

56.How to validate input values in Display file ?

Ans:With the help of Validity check key words VALUE, RANGE, COMP

57.How can see logical file based on which physical file and vice versa

Ans:DSPDBR

58.How can u check no of records in a file

Ans:DSPFD

59.How do u compile RPGLE program

Ans:Either thru 15 or crtrpgmod

60.Is module executable

Ans:No You need to create an RPG prog to run the module.

61.What is SFLPAG and SFLSIZ ?

Ans:

SFLPAG : it is an attribute which specifies the number of records that can be displayed in a screen.
SFLSIZ : it is an attribute which specifies the number of records can be stored in the subfile.

62.What are the three line types in RLU ?

Ans:Report line, Filler line & Sample line.

63.What is the function of RLU ?

Ans:To design & prototype a report.

64.List some of the commonly used commands for debugging

Ans:STRDBG(for batch jobs), STRISDB.

65.Define the RCVF command?

Ans:RCVF command used to receive the records either from the data base file or device file.

66.Define the purpose of the %SST function?

Ans:To extract the information from the specified string.

67.Define the purpose of the *CAT function?

Ans:To concatenate the two strings into a one string.

68.Define the purpose of the *BCAT function?

Ans:To concatenate the two strings by placing a single blank in a resultant.

69.Describe the difference between the DOWxx and DOUxx operations?

Ans:

DOWxx : If the condition becomes true, then only the group of instructions allowed executing.

DOUxx : Irrespective of condition, it will execute at least one time.

70.What is the difference between Packed decimal and Zoned decimal?

Ans:

Packed decimal : One digit occupies 1 byte.

Zoned decimal : One digit occupies 2 bytes.

71.What is default data type (if you define decimals ‘0’) in Physical file?

Ans:Packed decimal

72.What is default data type for the fields(sub fields) defined in data structures in RPG?

Ans:Zoned decimal

73.What is the difference between GOTO & EXSR?

Ans:EXSR is a conditional branching while a GOTO is an unconditional branching.

74.Difference between CA & CF?

Ans:CA: – It does not retains the value into the buffer memory. CF: – It retains the value into the buffer memory.

75.What does EXFMT does?

Ans:Write & Read.

76.What is term CUA , SAA?

Ans:

Common User Access
System Application Architecture

77. Define a Job Queue?

Job queues are queues of batch jobs waiting to be processed.

78. Define a Output Queue?

Output queues are queues of jobs waiting to be printed.

79. What is acronym of RPG?

Report Program Generator

80. What is the native language of AS/400?

RPG/400

81. Why RPG/400 is famous?

* Easy to code and analyze.
* Supports externally described files.

82. How do you use exceptional write in C specs?

Using EXCPT opcode.

83. What does the opcode FREE do?

The FREE operation removes a program from the list of activated programs, frees static storage and ensures program initialization (first cycle processing) the next time program is called. It does not close file or unlock data area.

84. What does opcode POST do?

Puts information in INFDS.

85.A Query can be displayed without saving it?

Ans:True

86.Which are the Query selection criteria, which can be given in a Query?

Ans:LIST

87.To add a file to the ‘File Selection’ option of a Query, the function key to be pressed is?

Ans:F9

88.A query can be run in which mode?

Ans:Batch & Interactive

89.What is the values SQLCOD when there is an error in fetching the records specified in the select statement?

Ans:-ve value

90.A file cannot have more than 1 unique key?

Ans:False

91.DLCOBJ command is mandatory for removing lock on any object?

Ans:False

92.What is a Journal?

Ans:A Journal is an object used primarily to record changes to data in a PF.

93.Which are the DB2 tools to protect Integrity of the database?

Ans:Journaling & Commitment Control, Referential Integrity Embedded SQL & Object/Record Locks.

94.How many types of display are available on As/400 for user interaction?

A.The 4 Types they are Entry, Menu, Information & List Display.

95.Which is the Primary Editor of As/400?

A.Source Entry Utility (SEU).

96.What are the basic features of SEU?

Prompt depending upon type, shows right hand side date & left hand side the line number.

97.What are the different methods to access SEU?

Use the Start Source Entry Utility command (STRSEU) Option 8 from STRPGMMNU Through Program Development Manager (PDM)

98.Which are the member types which SEU supports?

RPG, CL, PF, LF, PRTF & DSPF.

99.In which Specs Arrays, Tables & Constants are defined?

A.In I Specs.

100.What is a Spool File?

A.Printed output items placed in an output queue are known as spooled files.