AS400 FAQs, Interview Questions and Answers

What is a library in AS/400 ?
Ans:Library in AS/400 is an object that serves as a repository for other objects.

Name few IBM supplied libraries ?
Ans:GPL, QTEMP, QUSRTOOL, QSYS, QRPG & QCBL.

What is a library list ?
Ans:Library list that indicates libraries used for the process and the order in which it has to be
searched. System identifies it in *LIBL.

How many libraries can be there in a library list ?
Ans:Total 40 (15 system and 25 application).
DDS - Data Description Specification.
Source Physical File contains the source for the various objects created. This file has a specific structure.
RPG, CLP, DSPF, PRTF, etc.
A-spec
UNIQUE, PFILE, REFFLD


What is the difference between Physical and Logical files ?
Ans:Physical file contains data, where as Logical file serves as a access path to database.

What does the keyword UNIQUE mean ?
Ans:Records with duplicate key values are not allowed.

What is FCFO, FIFO, LIFO in Database environment ?
Ans:These are file level keywords which are used to access the records in the order
FCFO : First Changed First Out
FIFO : First In First Out
LIFO : Last In Fist Out

How many record formats can you have in a Physical file and in a Logical file ?
Ans:Physical file can contain only one record format, Logical file can contain more than one record format.

What is Multi-format logical file ?
Ans:Logical which uses fields from two or more physical files.

What is keyword PFILE specifies ?
Ans:PFILE is used define the Physical file being referenced.

What is a Join Logical File, Can it be used for Update ?
Ans:Logical file that combines more than one physical file.
Update is not possible through JLF.

Is it possible to join the same file to itself ?
Ans:Yes.

What does SDA stands for ?
Ans:Screen Design Aid.

What is the symbol used for defining a new field in SDA?
Ans:'+'.

What is the symbol used for shifting fields in SDA?
Ans:'<' , '>'.

What is the symbol used for copying & moving new field in SDA?
Ans:Copying : '-' & '=='.
Moving : '-' & '='.

What is the symbol used to get name & length of a field in SDA?
Ans:'?' .
*DATE, *TIME.

How can a screen field that has changed since the last output operation be detected ?
Ans:Attach the MDT attribute to the field, to detect whether field has been changed as a result of user input.

What are the different types of specification available in RPG/400 ?
Ans:Control Spec.( H )
File Spec.( F )
Extension Spec.( E )
Line counter Spec.( L )
Input Spec.( I )
Calculation Spec.( C )
Output Spec.( O )

Is it necessary to define all formats ? Which are mandatory and which are Optional ?
Ans:No, all are Optional.

What is the use of E specification in RPG ?
Ans:Extension Specs describes all record address files, arrays and tables.

In which specification can a report layout be defined ?
Ans:O Specification.

How many files can be defined in F specs ?
Ans:A maximum of 50 files.

Can an indexed file be accessed in arrival seQuence in RPG program ?
Ans:Yes.

In which specification Data Structures can be defined?
Ans:I - Spec.

When is a TAG statement used in RPG ?
Ans:It is used as a Label.

Source: aired.in