IBM AS/400
While enterprise computing was fragmenting among a multitude of incompatible systems, IBM was secretly preparing a machine that would shake up the established conventions. The AS/400 would be born in 1988 in the Rochester, Minnesota laboratories, far from the major research centers of the American East Coast. This particular gestation partly explains why this architecture developed such unique characteristics.
Frank Soltis's team had been working since 1978 on the System/38, a computer with pioneering concepts but modest commercial success. The Rochester engineers had chosen a radically different path from that explored by the creators of UNIX, VMS, or the future designers of Windows NT. Their approach remained so confidential that IBM did not share all the secrets of this architecture with its other divisions.
When the AS/400 was unveiled on June 21, 1988, the announcement surprised by its scope. Six processor models were offered simultaneously, accompanied by more than 1,000 ready-to-use applications. This immediate software availability constituted a record in the computer industry. The promised performance was impressive: memory was multiplied by 24, storage by 48, and computing power tenfold compared to previous generations.
The real innovation lay in the internal architecture. The AS/400 was based on a technology-independent machine interface called TIMI. Programs no longer communicated directly with the processor but with a virtual machine. This abstraction enabled a technical tour de force in 1995: IBM replaced the 48-bit CISC processors with 64-bit RISC PowerPC chips without any existing application requiring the slightest modification. All programs continued to function as if nothing had happened.
The system organized everything as objects. Files, programs, printers, users: each element had a precise description of its authorized uses and function. This object-oriented design, unusual for the time, strengthened security and simplified management. An administrator could manipulate any system component with the same standardized commands.
Integration constituted the other pillar of this architecture. Where systems laboriously assembled databases, security, communications, and backup tools from different vendors, the AS/400 natively incorporated all these functions into its operating system. DB2/400 managed data, security controlled every access, communication protocols were integrated. This unity drastically simplified daily administration.
Memory management revolutionized usual practices. The "single-level store" created a unique 64-bit address space, approximately 18 quintillion bytes. Programs and their data received permanent addresses in this gigantic space. No more juggling between main memory and secondary storage: the system automatically handled placing objects in the right location according to their usage.
The 1990s saw the AS/400 evolve to adapt to new needs. In 1994, the Advanced Series integrated Lotus Notes and Internet access. Portable models appeared, as well as versions intended for small organizations. Reliability improved by a factor of 20 between 1988 and 1992, while performance progressed by 30% each year.
Commercial success accompanied technical excellence. 250,000 systems from previous lines (System/34, /36, and /38) were already installed at launch. In 1992, IBM delivered the 200,000th AS/400 to Heineken brewery. These figures testified to massive adoption in companies worldwide.
The machine's identity evolved through IBM's acquisitions and marketing strategies. AS/400e, then eServer iSeries, eServer i5, System i5, System i, and finally IBM i in 2008. This last name emphasized the system's new capabilities, now able to simultaneously execute IBM i, AIX, and Linux on the same POWER hardware.
The development environment progressively modernized. The Integrated Language Environment replaced the old programming model by improving modular program performance. RPG and COBOL, the platform's historical languages, coexisted with C/400, Pascal, and Java. The command-line interface, recognizable by its mnemonics like WRKOBJ ("work with object"), survived all changes while enriching itself with modern graphical interfaces.
This exceptional longevity reveals the relevance of a different vision of enterprise computing. While most manufacturers developed modular systems assembling heterogeneous components, IBM Rochester prioritized integration, consistency, and ease of use. The AS/400 proves that an alternative approach to dominant standards can survive and prosper for more than three decades.