IBM OS/2

IBM OS/2. It was a family of computer operating systems initially created through a joint development agreement between IBM and Microsoft. Intended to succeed the DOS operating system, it introduced advanced features like a protected-mode GUI and preemptive multitasking. The partnership dissolved acrimoniously, leading IBM to continue development alone, positioning it as a competitor to Microsoft Windows and Unix in the corporate market.

History and development

The project originated in the mid-1980s as a collaborative effort between IBM and Microsoft, aimed at creating a successor to DOS for the Intel 80286 and later processors. Key figures included Bill Gates at Microsoft and a team at IBM led by executives in Boca Raton, Florida. The collaboration fractured over strategic differences, notably regarding the future of Microsoft Windows and the Intel 80386 processor. Following the split in 1990, IBM assumed full control, with subsequent versions developed at its Austin, Texas laboratory. The project was closely tied to the development of the IBM PS/2 line of personal computers and its Micro Channel architecture. Later development was influenced by the Taligent project and technology from Microsoft Windows NT.

Technical overview

OS/2 was engineered as a protected-mode operating system, initially for the Intel 80286 but later fully exploiting the Intel 80386. Its kernel was a hybrid kernel design, supporting true preemptive multitasking and multithreading. A key architectural feature was the presentation of a consistent API known as the Workplace OS in later versions. The system included a robust object-oriented programming framework and supported multiple file systems, including its native HPFS, which offered advantages over the FAT file system. It provided a virtual DOS environment superior to that of contemporary Microsoft Windows, allowing seamless execution of DOS applications. The Graphical user interface, initially the Presentation Manager, evolved significantly.

Software and compatibility

A wide range of software was developed for the platform, including the Lotus SmartSuite office applications and the Database Manager based on IBM DB2. Its strong DOS and early Microsoft Windows 3.x compatibility, via a subsystem, was a major selling point. Notable native applications included the IBM WebExplorer browser and client software for IBM LAN Server. The system also ran software from the Unix world through optional packages like the Open32 toolkit. Development tools were available from IBM, Watcom, and Borland, supporting languages like C++ and Rexx. The platform hosted early versions of Java (programming language) and the OpenDoc compound document architecture.

Market reception and legacy

OS/2 achieved notable success in certain vertical markets, particularly in banking, where it powered many ATM machines, and in branches of the United States government. It faced intense competition from Microsoft Windows, especially after the successful launch of Windows 95. Despite technical acclaim, it struggled with marketing, developer support, and the overwhelming dominance of the Wintel platform. Its legacy is evident in several IBM products; key components of its codebase and architecture were integrated into IBM Workplace, and its networking stack influenced IBM LAN Server. The object-oriented concepts explored in the Workplace OS project informed later work at IBM. Many of its advanced features, such as preemptive multitasking, later became standard in Microsoft Windows NT.

Versions and derivatives

The first version, OS/2 1.0, released in 1987, was a text-based system. Version 2.0, a major 32-bit release for the Intel 80386, introduced the object-oriented Workplace Shell. OS/2 Warp 3.0, launched in 1994, included integrated TCP/IP networking. The final major version was OS/2 Warp 4 (Merlin), released in 1996. Specialized derivatives included OS/2 Warp Server for network servers and OS/2 for PowerPC, which was canceled. The technology also lived on in IBM's eComStation and later ArcaOS, which are modern commercial distributions. Elements of the operating system were also utilized in the IBM 4690 OS for point-of-sale systems and embedded versions deployed in the Paris Métro and on the Boeing 777 aircraft.

Category:IBM operating systems Category:Discontinued operating systems