OS400 is an object-based operating system. If we are familiar with Windows in folders, files, txt and others, not with OS400 specifically. Basically, OS400 is based on UNIX, so we can still find objects based on the path. But the basis of OS400 is object based. Where all OS400 operations can be accessed based on these objects. OS400 objects are stored in a Library that is used as a place to hold objects (or in Windows it is known as a folder).
On the database side OS400 is the same. For example when creating a database on OS400, when creating a Schema, tables and so on it is stated to be object based if we are going to access it using a green screen or TN5250 terminal for OS400. If we create a DB2 OS400 database. When creating a MYDB schema, in OS400 an object named MYDB will be created with the * LIB (Library) object type. Likewise if we will create a table in the MYDB database schema, for example with the name MYTABLE, then on OS400 an object * FILE will be created with the name MYTABLE, and so on.
This is what I think is the advantage of OS400, we have various ways to manage the DB2 database that runs on OS400. We can use DB2 Admin or directly use the green screen access to the object.
The following OS400 objects are often used daily by me:
- *LIB – Library (where all objects are stored except for other libraries – there are no libraries in the library except the QSYS library).
- *FILE – File (object file in the form of a database or other type of data)
- *PGM – Program (compile program results such as CLP, RPGLE, C ++, cobol and others)
- *DTAARA – Data area (a kind of data reservoir that can be used by many jobs that are running)
- *JRN – Journal (object journal as a place to collect the results of recording system or database activities)
- *JOBD – Job Description (predefine the job as an attribute parameter when a job will be run)
- *JOBQ – Job Queue (job holding place that will run)
- *OUTQ – Output Queue (where the output from a processing output is stored)
- *SBSD – Subsystem Description (predefine a subsystem that runs on the system)
- *LIND – Line Description (object related to the configuration of the ethernet card or CMN that is on OS400)
The following objects on OS400:

To see in more detail these objects, visit the official IBM website.
If there is anything you want to ask, just type in comments.