AS/400 system is based on Layered machine architecture. It is the physical server built by IBM in the 1980s. It allows the user to move their application to new hardware at any time. It is object-oriented i.e. everything on the system is an object and the data is stored in files.
It is mostly used for business applications such as ERP, Banks, transportation & logistics, finance, and manufacturing industries, etc especially where safety, stability, and reliability are kept of utmost importance.
It has an integrated DB2 database management system. We can use different programming languages on the AS/400 system such as RPG, COBOL, CL, SQL, Assembly language, C, C++, Java, PHP, Python, REXX, Pascal, Perl, BASIC, PL/I, Smalltalk, EGL, etc.
Several CASE tools are available for AS/400 systems such as Accelerator for IBM i, Synon, LANSA, IBM Rational Business Developer Extension, etc.
The AS400 developer mostly uses RPG (Report Program Generator) programming language along with CL (Control Language) and SQL DB2. In the future, the AS/400 developers would be using Java, XML, etc on this system.
AS/400 systems are now enhanced to work well with the web application within distributed networks.
One interesting point is that Nobody can Hack an AS/400.
There are several terminal emulators that exist which provide access to the AS/400 systems such as Mocha TN5250 and 5250 emulators, IBM i ACS (Access Client Solutions), etc.
History and Evolution
Please have a look into the brief history of the AS/400 systems to the IBM i systems.
- The AS/400 system is called Application Server/400.
- The AS/400 system was introduced by IBM in 1988.
- The AS/400 system was the successor to the System/36 and System/38 platforms.
- The AS/400 system runs the OS/400 operating system.
- The AS/400 system is Technology Independent Machine Interface (TIMI).
- The AS/400 system is platform-independent instruction set architecture i.e. compiled with machine language instruction.
- In 1994, For all the new models the name being used was AS/400 Advanced Series.
- Later In 1997, the name being used for the system was AS/400e (e stands for e-business).
- Later In 2000, IBM renamed the AS/400 system to eServer iSeries.
- Later In 2004, the iSeries changed to eServer i5 and OS/400 to i5/OS.
- The AS/400 system was renamed System i in 2006.
- Further in 2008, System i merged with System p and become IBM Power Systems.
- At the same time, the i5/OS was renamed IBM i.
Nowadays IBM i system uses ILE (Integrated Language Environment) programming environment which allows us to create single programs from different modules from different ILE compatible languages such as (C, C++, RPG, CL, COBO, etc).