Consultancy > AS/400 > AS/400 Operating System
AS/400 Family
The AS/400 operating system is OS/400, later renamed i5/OS.
The AS/400 (iSeries – IBM i) operating system is “proprietary”, i.e. produced and implemented solely by IBM.
Developed and managed by IBM, it forms a whole with the DB2/400 database integrated into the system.
Broadly speaking, the AS/400 operating system consists of two parts: the “machine interface” part and the command management code.
The MI is a layer of software designed to interface with the machine hardware.
The commands to obtain the machine control functions (spool, work, telecommunications, etc.) interface with the MI and not directly with the hardware.
This allows you to separate the type of hardware from the actual operating system.
Paradoxically, with the proper MI for a PC hardware setup, you could run the AS/400 operating system on a personal computer.
Access to MI is almost completely closed to programmers. This makes the structure very robust because it prevents you from “tinkering” with the “core” functions of the system.
The closed and proprietary structure of the system allows the AS/400 to be largely immune to viruses and hacker attacks.
Even operating system updates are risk-free due to the closed structure that prevents conflicts between software from different vendors.
From an operational point of view, the system management functions are performed via command line in a way similar to Windows’ “power shell” (although, historically, it would be more accurate to say that Windows’ power shell is similar to the command line of AS/400).
Command input is assisted, that is, it is always possible to use a prompt that breaks down the command in its parameters by controlling the syntax and providing both general help with the command and help with individual parameters, enumerating the possible options for each field.
The commands are always structured according to a sequence like “verb” + “object” with contracted names.
For example, to get a display of the prints (spool) of the user, you have to type the command: WRKSPLF username (WRK + SPLF = Work + Spooling File).
In the example above, the request is to manage (work) the prints of the user “mariorossi”.
By pressing F4, instead of enter, the command prompt will be displayed (see below).
Where you can change the parameters of the command to display, for example, prints from a certain printer only.
After confirming, here is the final result:
Each line represents a print, which can be displayed, deleted, etc.
This example shows the typical operating mode to get all kinds of functions on AS/400.
Other example commands:
WRKACTJOB = WORK with ACTIVE WORK (manage Active jobs on the system)
WRKUSRPRF = WORK with USER PROFILE (manage User Profiles)
DLTF = DELETE FILE (delete a Data Table)
CRTOUTQ = CREATE OUT QUEUE (Create a print queue)
WRKLIB = WORK LIBRARY (manage the contents of a Library)
This list is a tiny extract from the AS/400’s general command list that consists of thousands of commands for each type of operation.
If you prefer to use a graphical interface to the essential approach of the command line interface, you can use the “Operations Navigator” program offered by “System i Access”.
The system functions are listed in the left pane.
Since the “Print Output” function is selected, the right pane lists the same prints as shown in the previous image in graphic format.
A first way to continue our in-depth look at the AS/400 operating system is to consult the basic operations manual of the system, available at the following link for version 7.5 of the operating system, the latest on the market at the date of writing this text: https://www.ibm.com/docs/en/ssw_ibm_i_75/pdf/rzal2pdf.pdf
More broadly, you can consult the Information Center for “IBM i” (AS/400) at the following link: https://www.ibm.com/docs/en/i/7.5
The Information Center allows you to consult the vast online documentation for AS/400 systems offered by IBM allowing you to also carry out targeted research on individual topics.