AS400 Interview Questions

What does ‘AS’ in AS400 stands for?

Application system.

What is ‘LPAR’?

OS/400 Version 4, introduced a feature LPAR (Logical PARtitioning) which facilitates running multiple operating systems simultaneously on one IBM System i unit ensuring that one OS doesn’t interfere other’s system resources/memory.

What is library is AS400? What are the types of library?

When we execute a command or call a program, the  AS/400  must know where to find the command or program and the answer is library. A Library is a collection of objects. QSYS is the only library that contains other library. QSYS is the root library where the entire user defined/ system defined library is created. System supplied libraries begin with the letter “Q” or “#”.

Library list types:

System library: All IBM supplied library e.g. QSYS, QHLPSYS, QUSRSYS…

Product Library: Whenever Ibm product is used it is added to the library automatically and is removed itself when the job completes.

Current Library: Current library is the working library i.e. all the work done by you is stored in current library.

User Library: Non-IBM supplied i.e. created by the user.

Which library gets first loaded into the system when we login?


Is QGPL a user library or system library?

It’s a user library.

How can we see all the objects and its sizes in a library?

By using the command DSPLIB.


It gives you the information of all objects that resides in the library with it size.

Display Library

Library  . . . . . . :   IROBO1          Number of objects  . :   8

Type . . . . . . . . :   PROD            Library ASP number . :   1

Create authority . . :   *EXCLUDE        Library ASP device . :   *SYSBAS

Type options, press Enter.

5=Display full attributes   8=Display service attributes

Opt  Object      Type      Attribute               Size  Text

PRINT1PGM   *PGM      RPGLE                 131072  rpgle program for pri

ACCOUNT     *FILE     PF                     49152  ACCOUNT RELATED INFOR

PRINT1      *FILE     PRTF                    4096  PRINTER DDS RLU GENER

QCLSRC      *FILE     PF                      8192  Sources CL-Programs

QDDSSRC     *FILE     PF                      8192  DDS-Sourcen

QRPGLESRC   *FILE     PF                     69632

QRPGLESRC2  *FILE     PF                     65536

QRPGSRC     *FILE     PF                      8192  SOURCE PHYSICAL FILE


F3=Exit   F12=Cancel   F17=Top   F18=Bottom

What is source physical file?

Source physical file is a file which contains the sources of different types of objects. There can be up to 32768 members. Source physical file is an object. But the source member is not an object. When we compile the member, the object is created for that source. Command used is CRTSRCPF.


How to see all members of a file?

By using the command shown below:


How to see all record formats used in a file?

By using the command shown below:


How to change the record size of a physical file?

By using the command below:


We change the highlighted part to change the size of a file.

Change Physical File (CHGPF)

Type choices, press Enter.

Physical file  . . . . . . . . .                 Name

Library  . . . . . . . . . . .     *LIBL       Name, *LIBL, *CURLIB

System . . . . . . . . . . . . .   *LCL          *LCL, *RMT, *FILETYPE

Source file  . . . . . . . . . .   *NONE         Name, *NONE

Library  . . . . . . . . . . .                 Name, *LIBL, *CURLIB

Member size:

Initial number of records  . .   *SAME         1-2147483646, *NOMAX, *SAME

Increment number of records  .   *SAME         0-32767, *SAME

Maximum increments . . . . . .   *SAME         0-32767, *SAME