Editing Workplace OS (section)

==Overview==
===Objective===
By 1990, IBM acknowledged the software industry to be in a state of perpetual crisis. This was due to the chaos from the inordinate complexity of software engineering inherited by its legacy of [[procedural programming]] practices since the 1960s. Large software projects were too difficult, fragile, expensive, and time-consuming to create and maintain; they required too many programmers, who were too busy with fixing bugs and adding incremental features to create new applications. Different operating systems were alien to each other, each of them running their own proprietary applications. IBM envisioned "life after maximum entropy" through "operating systems unification at last"<ref name="Life After Maximum Entropy"/> and wanted to lay a new worldview for the future of computing.

IBM sought a new world view of a unified foundation for computing, based upon the efficient reuse of common work. It wanted to break the traditional monolithic software development cycle of producing [[Software testing#Alpha testing|alphas]], then [[Software testing#Beta testing|betas]], then testing, and repeating over the entire operating system — instead, compartmentalizing the development and quality assurance of individual unit objects.<ref name="OWCPE book"/>{{rp|19}} This new theory of unifying existing legacy software and the new way of building all new software, was nicknamed the Grand Unified Theory of Systems or GUTS.<ref name="OWCPE book"/>{{rp|20}}

Coincidentally, Apple already had a two-year-old secret prototype of its [[microkernel]]-based [[object-oriented operating system]] with application frameworks, named [[Taligent#Pink system|Pink]].<ref name="OWCPE book"/>{{rp|20}} The theory of GUTS was expanded by Pink, yielding Workplace OS.

===Architecture===
IBM described its new [[microkernel]] architecture as scalable, modular, portable, client/server distributed, and open and fully licensable both in binary and [[source code]] forms.<ref name="OWCPE book"/>{{rp|376–377}} This microkernel-based unified architecture was intended to allow all software to become scalable both upward into [[supercomputing]] space and downward into mobile and embedded space.<ref name="OWCPE book"/>{{rp|18–19}}

Leveraged upon a single microkernel, IBM wanted to achieve its grand goal of unification by simplifying complex development models into reusable objects and frameworks, and all while retaining complete backward compatibility with legacy and heritage systems.<ref name="OWCPE book"/>{{rp|3}} Multiple-library support would allow developers to progressively migrate select source code objects to 64-bit mode, with side-by-side selectable 32-bit and 64-bit modes. IBM's book on Workplace OS says, "Maybe we can get to a 64-bit operating system in our lifetime."<ref name="OWCPE book"/>{{rp|19}} IBM intended shareable objects to eventually reduce the footprint of each personality, scaling them down to a handheld computing profile.

At the base of Workplace OS is a [[Fork (software development)|fork]] of the [[Mach kernel|Mach 3.0]] microkernel (release mk68) originally developed by [[Carnegie Mellon University]] and heavily modified by the [[Open Software Foundation]]'s Research Institute. Officially named "IBM Microkernel",<ref name="Why did Taligent fail"/><ref name="Half an operating system"/><ref name="Transforming Your Business"/>{{rp|14–15}}<ref name="Inside Taligent Technology"/>{{rp|119}} it provides five core features: IPC, virtual memory support, processes and threads, host and processor sets, and I/O and interrupt support.<ref name="Small Kernels Hit It Big"/>

On top of the IBM Microkernel is a layer of shared services (originally called Personality Neutral Services or PNS<ref name="OWCPE book"/>{{rp|3}}) to cater to some or all of the personalities above them. Shared services are endian-neutral,<ref name="Life After Maximum Entropy"/><ref name="OWCPE book"/>{{rp|24}} have no user interface, and can serve other shared services.<ref name="OWCPE book"/>{{rp|379}}<ref name="Life After Maximum Entropy"/> ''Byte'' summarizes that shared services "can include not only low-level file system and device-driver services but also higher-level networking and even database services. [Workplace OS's 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 driver]]s." This layer contains the file systems, the scheduler, network services, and security services. IBM first attempted a device driver model completely based in userspace to maximize its dynamic configuration, but later found the need to blend it between [[user space and kernel space|userspace and kernelspace]],<ref name="Small Kernels Hit It Big"/> while keeping as much as possible in userspace.<ref name="OWCPE book"/>{{rp|176}} The Adaptive Driver Architecture (ADD) was designed for the creation of layered device drivers, which are easily portable to other hardware and operating system platforms beyond Workplace OS,<ref name="OWCPE book"/>{{rp|174}} and which consist of about 5000-8000 lines of device-specific code each.<ref name="OWCPE book"/>{{rp|378}} Some shared services are common only to select personalities, such as MMPM serving multimedia only to Windows 3.1 and OS/2 personalities, and which is alien or redundant to other markets.<ref name="Life After Maximum Entropy"/>

Atop the shared services, another layer of userspace servers called personalities provide [[DOS]], [[Microsoft Windows|Windows]], [[OS/2]] (Workplace OS/2), and [[UNIX]] (WPIX) environments.<ref name="Life After Maximum Entropy"/> The further hope was to support [[OS/400]], [[AIX operating system|AIX]], [[Taligent | Taligent OS]], and [[MacOS]] personalities.<ref name="Dimpfel">{{cite interview | interviewer=Stuart J. Johnson | first=Lois | last=Dimpfel | magazine=InfoWorld | page=106 | date=November 22, 1993 | title=Big Blue's Dimpfel has high hopes for Workplace OS | url=https://books.google.com/books?id=ATsEAAAAMBAJ&dq=comdex+1992+workplace+os&pg=PT1 | access-date=September 20, 2017}}</ref> Personalities provide environment subsystems to applications.<ref name="Small Kernels Hit It Big"/> Any one personality can be made dominant for a given version of the OS, providing the desktop user with a single [[GUI]] environment to accommodate the secondary personalities. In 1993, IBM intended one release version to be based upon the OS/2 Workplace Shell<ref name="OS/2 PPC"/> and another to be based upon the UNIX [[Common Desktop Environment]] (CDE).<ref name="Windows NT and Workplace OS"/>

IBM explained the branding: "Workplace OS is the [[codename]] for a collection of operating system components including, among others, the IBM Microkernel and the OS/2 personality. Workplace OS/2 is the specific codename for the OS/2 personality. Workplace OS/2 will operate with the IBM Microkernel and can be considered OS/2 for the PowerPC."<ref name="Just Good Old OS/2"/> For the 1995 final preview release, IBM continued, "When we stopped using the name 'Workplace' and started calling the product 'OS/2 for the PowerPC', you might have thought that the 'Workplace' was dead. But the 'Workplace' is far from dead. It has simply been renamed for prime time."<ref name="OWCPE book"/>{{rp|1,375}} Workplace OS/2 was intended to define the future of OS/2, as a 32-bit clean platform and free of internal legacy, with perfect compatibility for source code of OS/2 applications and drivers. IBM originally wanted to prove new development models on Workplace OS/2 and backport them into OS/2 2.1 for x86 until the two platforms were unified{{mdash}}especially the IBM Microkernel, a new graphics subsystem, fully 32-bit system code with a [[flat memory model]],<ref name="Graphics Subsystem">{{cite web | title=The OS/2 Graphics Subsystem in the Workplace OS Family | first=Kelvin | last=Lawrence | publisher=[[IBM]] | work=Developer Connection News | via=EDM/2 | url=http://www.edm2.com/index.php/The_OS/2_Graphics_Subsystem_in_the_Workplace_OS_Family | access-date=August 17, 2022}}</ref> Taligent, and [[OpenDoc]].<ref name="Advancing"/>

IBM intended for Workplace OS to run on several processor architectures, including [[PowerPC]], [[ARM architecture|ARM]], and [[x86]]<ref name="Dimpfel"/><ref name="WorkplaceMicrokernelandOS"/>{{rp|22}} which would range in size from handheld [[Personal digital assistant|PDA]]s<ref name="IBM shows Workplace OS"/><ref name="Advancing">{{cite magazine | title=Workplace: Advancing the State of the Art | first1=Miles | last1=Barel | first2=Jeri | last2=Dube | magazine=Innovations | issue=2 | series=Developer Connection News | volume=5 | date=1994 | publisher=[[IBM]] | via=EDM/2 | url=http://www.edm2.com/index.php/Workplace:_Advancing_the_State_of_the_Art | access-date=August 17, 2022}}</ref> to [[workstation]]s to large 64-bit servers and supercomputers.<ref name="OWCPE book"/> IBM saw the easy portability of the Workplace OS as creating a simple migration path to move its existing x86 (DOS and OS/2) customer base onto a new wave of [[Common Hardware Reference Platform|standard reference]] PowerPC-based systems, such as the [[IBM PC Series#PC Power Series|PC Power Series]] and the [[Power Macintosh]]. Creating a unique but open and industry-standard reference platform of [[open-source software|open-source]] microkernel, IBM hedged its company-wide operating system strategy by aggressively attempting to recruit other operating system vendors to adopt its microkernel as a basis for their proprietary operating systems.