4 Facts About OS/400 

  • The OS/400 was designed to run on AS/400 hardware.
  •  OS/400 was divided into System Licensed Internal Code (SLIC) and Extended Control Program Facility (XPF) controlled by the Technology Independent Machine Interface (TIMI). 
  • Since its release in 1988, the OS/400 has had name changes and developed into better versions which have added value to its AS/400 mainframe. 
  • The OS/400 is still a competitive operating system and still runs on some mid-range computers. 

What is OS/400: Explained

The operating system OS/400 was designed to run on AS/400 hardware and have both been upgraded and names changed over the years. Although OS/400 has continuously been upgraded and revised, it is still a competitive software because its compatibility feature enables users to access programs created on OS/400 years ago on an IBM mainframe today.

The OS/400 is perfectly designed to help companies in Enterprise Resource Planning (ERP) processes. Therefore, it’s widely used by firms seeking to integrate its planning, Purchase inventory, manage its sales, marketing, and finance.

How to use OS/400

OS/400 was divided into System Licensed Internal Code (SLIC) and Extended Control Program Facility (XPF) controlled by the Technology Independent Machine Interface (TIMI). TIMI was a hardware abstraction layer that split the hardware-dependent and hardware-independent system on OS/400. Therefore, a user can run an operating system and application software on separate hardware without re-compiling.

OS/400 uses the Report Program Generator (RPG) programming language developed in 1959 for IBM computers. Below is a tutorial on operating the OS/400 computer system. 

When you start your computer, the OS/400 system will display the Menu on the screen with a list of its custom options depending on your computer settings. Below the menu options are the command line that enables you to type in instructions that the system will read and respond to. After the command line, you get to the Function Keys, which provide a shortcut while executing some functions, for example, the F3-exit, F4-prompt, and F12-cancel. Finally, you will see an information area down the screen which displays messages depending on the current operation. 

Now, the GO command tutorial will help you navigate through the menu options quickly. If you want to use the GO command, you will first type the word “go” on the command line followed by the Menu you wish to. For example: if you need the program menu, you will type “go program”, and the system will directly show the options on that menu. Additionally, you can use the number option tutorial to navigate through menus by typing the number of menu options you need on the command line. Lastly, you can quickly access the menu option by typing the Menu title you need on the command. You can use the F12 key on every step above to cancel your choice and get back to the main menu.

Another tutorial is how you can remove, change or re-number your menu options. Starting on removing the OS/400 menu, you will click on the option number, then replace it with a zero (0) and press ENTER. The second step is changing the menu option number. Place your cursor right after the option number, switch to your desired figure, and press ENTER. Finally, you can re-number the menu options by pressing the F4 function key, automatically doing the process. 

The Difference Between OS/400 vs UNIX

  1. OS/400 is an object-based system with an Integrated Database Management System (IDBMS), while UNIX is a text-based operating system with a Relationship Database System (RDB). Although it might be challenging for beginners to use the Object-based system, OS/400 is much more reliable and secure, making it the best data protection than UNIX.
  2. OS/400 uses Single-level storage, while UNIX supports the UNIX file system. The OS/400 system takes the entire storage as a single two-dimensional plane of addresses. Pages may be in primary storage (RAM) or secondary storage (disk). Contrary, the UNIX file system organize and store large files in a small unit, making it easy to manage. Therefore, UNIX operating system performs better than OS/400 in file management. 
  3.  OS/400 controls its hardware using the System Licenced Internal Code (SLIC) while UNIX uses the Unix Kernel. Both the hardware layers are good, but if you are looking for a more secure and complete file recovery system, the SLIC system in OS/400 is the best. This is because it is enabled with Technology Independent Machine Interface (TIMI), which allows the operating system and application programs to take advantage of advances in hardware and software without recompilation. 
  4. OS/400 uses the RPG programming language, while UNIX uses the C programming language. The C programming language made UNIX exceptional and ran on numerous platforms. Unlike the RPG, the C programming system was portable, making UNIX more convenient than the OS/400. 

OS/400 Release History

OS/400 (later renamed to i5/OS and IBM i) was introduced on June 21, 1988, and officially released on August 26, 1988, to run on the AS/400 (later renamed to iSeries, System i, and Power Systems) mainframe. IBM’s chief scientist for the AS/400 computers was Frank Gerald Soltis, a US computer scientist with a pioneering contribution in TIMI and single-level storage architecture.

Frank Soltis
Frank Gerald Soltis

Since its release in 1988, the OS/400 has had name changes and developed into better versions which have added value to its AS/400 mainframe. The OS/400 is still a competitive operating system and still runs on some mid-range computers. Here is its development over the years. 

V1R1 (August 26, 1988)

it was the first released version of OS/400 and was initially called Release 1. 

V1R1M2 (November 25, 1988)

It was an upgrade on the system/36 to Release 5 Modification Level 1 and System/38 to release 8 modification level 0

V1R2 (October 27, 1989)

It was also called the Release 2 version and had enhancements on the IBM cloud storage system. 

V1R3 (September 28, 1990)

It is commonly known as IBM SanFrancisco V1R3 and was developed with the Formerly Independent software Vendors to better the experience of corporate developers. 

V2R1 (May 24, 1991) 

It was built with special features such as the BookManager, EREP, and High-Level Assembler.

V2R1M1 (March 06, 1992)

This version had new compiler options and sub-options such as ARCH (11), allowing users to navigate the OS/400 system quickly. It also had the new macros, the hardware model, and feature built-ins.

V2R2 (September 18, 1992)

It was an upgrade of the V2R1 version and was developed with an advanced Base Control Program (BCP) and the workload manager (WLM).

V2R3 (December 17, 1993)

It had advanced features compared to V2R2, such as the BCP (MVSTM) and Cryptographic services enhancements. 

V3ROM5 (May 04, 1994)

This version had advancements in the DFSMS software, such as new copy services, DFSMSdfp utility functions, and DFSMD Object Access Method (OAM).

V3R1 (December 22, 1996)

It was an improved version of IBM Enterprise COBOL, which could use its function to integrate COBOL businesses. 

V3R2 (June 21, 1996)

It was developed to act promptly on PL/I V3R2 with a system to support NOMAP and NOMAPIN.

V3R6 (December 22, 1995)

This version was also called Tivoli Enterprise Console V3R6, which was the system that supported the Tivoli framework-based management to run on IBM mainframe. 

V3R7 (November 08, 1996)

This version had advancements in the software terms and ordering information. It had Application development ToolSet Plus and changes to ValuPak and Growthpak.

V4R1 (August 29, 1997)

It had changes in order structure such as the Lotus (R) Enhancedpak and had the OS/400 user charges removed.

V4R2 (February 27, 1998)

It was an extension of the TCP/IP intranet and was developed with special features to boost the E-Business feature. 

V4R3 (September 11, 1998)

This version enhanced the server Basepak to make it user-friendly and provide additional functions. 

V4R4 (May 21, 1999)

It was an upgrade on Function Printing Utilities (AFP/U) and had changes in Backup Recovery and Media Services (BRMS).

V4R5 (July 28, 2000)

This version was developed with an advanced Enhanced Extreme Support Personalized (ESP) and could allow users to monitor system performance remotely.

V5R1 (May 25, 2001)

It was created to provide a complete package for e-business and had the InfoPrint server that allowed an electronic output management system.

V5R2 (August 30, 2002)

It was the last version developed under OS/400 system. It had the DBCS Printer support and advanced Cryptographic support. 

V5R3 (June 11, 2004)

It was the first release after the OS/400 was renamed to i5/OS system. It had an advanced Job scheduler and the DB2 Query Manager.

V5R4/ 5.4 (14 February 2006)

It was designed on the i5/OS software and had simplified IT infrastructure and advanced security and compliance. 

V6R1/ 6.1 (March 21, 2008)

It was the last version developed under i5/OS software. It had the advanced International Components for Unicode Based sort support (IUC-Based). 

V6.1.1 (October 23, 2009)

The first developed version after i5/OS has been renamed IBM i software. It was developed with the IBM Tivoli Directory Integrator, which had the Real-time synchronization of data. 

V7.1 (April 23, 2010)

It was a version with major advancements in Technology Refreshments (TR) and improvement in language version media. 

V7.2 (May 02, 2014)

It upgraded the V7.1 and had enhancements on IBM QRadar integration and the SAML V2.0 single sign-on. 

V7.3 (April 15, 2016)

The latest release of IBM i is 7.3, launched in April, 2016. This version was developed with the new LogCollector Tool, which has improved the command-line interface. Also, it is integrated with IBM Business Process Manager. It is developed with new trigger attributes, including CREATE and ALTER TRIGGER. It also had advancements in HTTP functions in QSY2. 

Photoshop 1.0 splash screen
OS/400 release history

OS/400: End of development

Although OS/400 had its latest version released two years ago under the IBM i software, its mainframe was September 30, 2013. It has since been succeeded by IBM Power Systems, which is still used today.

IBM OS/400 Guide: History, Origin, and More  FAQs (Frequently Asked Questions) 

What is IBM OS/400?

IBM OS/400 was an operating system designed for AS/400 computers. 

When was IBM OS/400 launched?

It was released on June 21, 1988.

Who created IBM OS/400?

The author of IBM OS/400 was IBM’s Chief Scientist, Frank Gerald Soltis.

What is the IBM OS/400 called now?

It is currently called the IBM i software. 

Does IBM still support OS/400?

The last version to be released under the OS/400 software was no longer supported as of April 30, 2009. However, all the data stored on the OS/400 system is present on the latest IBM i version, which IBM still supports. Therefore, OS/400 could still be supported by IBM under the IBM i software. 

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