Workplace OS

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Workplace OS
Written inC
Working stateHistoric
Source modelProprietary
Marketing targetCorporate
PlatformsIA-32, PowerPC, ARM
Kernel typeMicrokernel
Default user interfaceWorkplace Shell

Workplace OS is IBM's experimental operating system of the 1990s. Starting development in 1991, the ambitious goal of Workplace OS was to unify and simplify the computing industry by migrating it to a common microkernel operating system base and PowerPC hardware base. The platform was intended to improve software portability and maintenance costs by aggressively recruiting all vendors to port their existing operating systems to run as concurrent personalities on Workplace OS. Committing IBM to a new strategic direction for the entire company, the project was intended also as a trendsetter toward PowerPC hardware platforms, to compete with the dominant Intel.

With protracted development spanning four years and $2 billion (or 0.6% of IBM's revenue for that period), the project suffered from feature creep and the second-system effect. In October 1995, the product was commercially introduced for a few models of IBM PowerPC hardware and the entire project was immediately discontinued.[1] In 1996, a second and final version was released that also supported x86 and ARM processors.[1]:22

A University of California case study described the Workplace OS project as "one of the most significant operating systems software investments of all time" and "one of the largest operating system failures in modern times".[1]:22


We have not closed discussion on [Mac OS support]. We're talking with Apple about including the Macintosh OS as one of the personalities in the microkernel.

—Lois Dimpfel, IBM's Director of Personal Operating Systems, in November 1993[2]

At the base of Workplace OS is a version of the Mach 3.0 microkernel (release mk68) originally developed by Carnegie Mellon University and heavily modified by the Open Software Foundation's Research Institute. This microkernel provides five core features: IPC, virtual memory support, processes and threads, host and processor sets, and I/O and interrupt support.[3]

On top of the Workplace OS microkernel, IBM placed Personality Neutral Services (PNS) to cater to all personalities above it. Byte summarizes that "PNSes can include not only low-level file system and device-driver services but also higher-level networking and even database services. [Lead architect Paul Giangarra] believes that locating such application-oriented services close to the microkernel will improve their efficiency by reducing the number of function calls and enabling the service to integrate its own device drivers." This layer contains the file system, the scheduler, and network and security services. IBM attempted a device driver model completely based in userspace to maximize its dynamic configuration, but found the need to blend it between userspace and kernelspace.[3]

Above the PNS, the operating system personalities run in the form of user-space servers that execute DOS, OS/2, and UNIX—with further intentions to support Microsoft Windows, OS/400, AIX, Taligent, and MacOS personalities.[2] Personalities provide environment subsystems to applications.[3] Any one personality can be made dominant for a given version of the OS, providing a single graphical environment to accommodate the secondary personalities. IBM planned one version to be based upon the OS/2 Workplace Shell[4] and another to be based upon the UNIX Common Desktop Environment (CDE).[5]

IBM had planned for Workplace OS to run on several processor architectures, including PowerPC, ARM, and x86 computers, and ranging in size from PDAs[6] to workstations to large servers. IBM saw the easy portability of the Mach-based Workplace OS as creating a simple migration path to move its existing x86 (DOS and OS/2) customer base onto PowerPC-based systems. IBM hedged its operating system strategy by aggressively trying to recruit other computer companies to adopt its microkernel as a basis for their own operating systems.


The project was conceived in January 1991, with an internal presentation of IBM's new strategy for operating system products. This included a chart called the Grand Unification Theory of Operating Systems, abbreviated as GUTS. The first small team began work in late 1991 with a prototype in mid 1992.[1] The initial internal-development versions of Workplace OS ran on x86-based hardware and provided a BSD Unix derived personality and a DOS personality.

At Comdex of 1992, IBM successfully demonstrated a Mach-based system running OS/2, DOS, 16-bit Windows, and Unix applications.[1] In 1992, IBM persuaded Taligent to replace its own internally developed microkernel with the IBM microkernel. Ostensibly, this would have allowed Taligent's operating system (implemented as a Workplace OS personality) to execute side-by-side with DOS and OS/2 operating system personalities.

By January 1994, the IBM Power Personal Systems Division had still not yet begun testing its PowerPC hardware with any of its three intended launch operating systems: definitely AIX and Windows NT, and hopefully also Workplace OS.[7] Software demonstrations showed limited personality support, with the dominant one being the OS/2 Workplace Shell desktop, and the DOS and UNIX personalities achieving only fullscreen text mode support with crude hotkey switching between the environments.[5] Byte reported that the multiple personality support promised in Workplace OS's conceptual ambitions was more straightforward, foundational, and robust than that of the already-shipping Windows NT. The magazine said "IBM is pursuing multiple personalities, while Microsoft appears to be discarding them" while conceding that "it's easier to create a robust plan than a working operating system with robust implementations of multiple personalities".[5]

In April 1994, Byte reported that, under lead architect Paul Giangarra,[5] IBM had staffed more than "400 people working to bring [Workplace OS] up on Power Personal hardware".[7]

In October 1995, IBM made the first commercial release of Workplace OS featuring Version 1 of the PowerPC kernel with the OS/2 personality and a new UNIX personality. The UNIX personality was offered as a holdover due to IBM's inability to port AIX as a Workplace personality due to incompatible endianness, but was abandoned. Many vendors and universities had adopted this microkernel for research.[1] In 1996, a second version was released that also supported x86 and ARM processors.[1]:22


The Workplace OS project was finally canceled in October 1995 due to myriad factors: poor performance; low acceptance of the PowerPC Reference Platform, upon which the initial offering ran; poor quality of the PowerPC 620 platform; extensive cost overruns; lack of AIX, Windows, or OS/400 kernel personalities; and the ultimately resulting low customer demand. Upon cancellation, IBM closed both the Workplace OS project and the Power Personal Division responsible for low-end PowerPC processors.[1] The other long-term effect was that IBM decided to stop developing new operating systems, and committed heavily to using Windows and Linux.

In 1997, a case study of the history of the development of Workplace OS was performed by the University of California with key details verified by IBM personnel. These researchers concluded that IBM had relied throughout the project's history upon multiple false assumptions and overly grandiose ambitions, and had failed to apprehend the inherent difficulty of implementing a kernel with multiple personalities. IBM considered the system mainly as its constituent components and not as a whole, in terms of system performance, system design, and corporate personnel organization.[1]:22 IBM had not properly researched and proven the concept of generalizing all these operating system personalities before starting the project.[1]:21 IBM believed that all the resultant performance issues would be mitigated by eventual deployment upon PowerPC hardware.[1]:22 The Workplace OS product suffered the second-system effect, including feature creep.[1]:21 The report described the Workplace OS project as "one of the most significant operating systems software investments of all time" and "one of the largest operating system failures in modern times".[1]:22

See also[edit]


  1. ^ a b c d e f g h i j k l m Fleisch, Brett D; Allan, Mark (September 23, 1997). "Workplace Microkernel and OS: A Case Study". John Wiley & Sons, Ltd. Archived from the original on August 24, 2007. Retrieved March 25, 2013.
  2. ^ a b Dimpfel, Lois (November 22, 1993). "Big Blue's Dimpfel has high hopes for Workplace OS". InfoWorld (Interview). Interviewed by Stuart J. Johnson. p. 106. Retrieved September 20, 2017.
  3. ^ a b c Varhol, Peter D. (January 1994). "Small Kernels Hit It Big". Byte. Archived from the original on March 7, 2006. Retrieved September 20, 2017.
  4. ^ "OS/2 Warp, PowerPC Edition". OS/2 Museum. Retrieved September 21, 2017.
  5. ^ a b c d "Windows NT and Workplace OS: Plug It In Article". Byte. January 1994. Archived from the original on May 29, 2006. Retrieved September 20, 2017.
  6. ^ Fitzgerald, Michael (July 4, 1994). "IBM shows Workplace OS for handhelds". Computerworld: 28. Retrieved September 20, 2017.
  7. ^ a b Thompson, Tom; Ryan, Bob (April 1994). "Apple, IBM Bring PowerPC To The Desktop". Byte. Archived from the original on April 14, 2005. Retrieved September 20, 2017.