Locus Computing Corporation

Locus Computing Corporation was an American software company formed in 1982 by Gerald J. Popek, Charles S. Kline, and Gregory I. Thiel to commercialize technology developed through the LOCUS distributed operating-system project at the University of California, Los Angeles. The company worked at the intersection of Unix, distributed computing, operating-system virtualization, multiprocessing, and high-availability clustering. Locus's principal technical contribution was the commercialization of a single-system image approach. This model sought to make a collection of networked or clustered computers appear to users and applications as one coherent system rather than as a set of separately administered machines. The company's work extended concepts associated with distributed process management, shared system resources, and transparent access across nodes. These capabilities were adapted for several major computer-industry partners and platforms. The company developed AIX variants for IBM's PS/2 and System/370 product lines. In that work, elements of Locus technology were incorporated into IBM's AIX Transparent Computing Facility, commonly identified as AIX TCF. Locus also produced OSF/1 AD, an advanced-development multiprocessor version of OSF/1 for Intel's Paragon massively parallel computer. To support process migration and communication across Paragon nodes, Locus reworked its technology into Transparent Network Computing, or TNC, and introduced the virtual-process, or VPROC, concept. Locus was also known for Merge, a virtualization and compatibility product that allowed DOS software, and later selected Windows software, to run on Unix systems. The product began in the mid-1980s for the AT&T 6300+ and was subsequently adapted for Unix environments including Microport SVR3, SCO Unix, and UnixWare. Merge addressed an important market problem: organizations that wanted Unix's multiuser operating environment but still depended on the large installed base of DOS and Windows applications. Locus later participated in Microsoft's WISE program, which gave it access to Windows source code and supported later efforts to run packaged Windows applications. Another important offering was PC-Interface, a LAN-based cross-platform integration toolkit. It used Unix as a file-system and integration hub while providing client connectivity for MS-DOS, Windows, Macintosh, and Unix systems. The toolkit supported a range of Unix platforms, including AIX, SCO Unix, UnixWare, and Motorola 9000 systems. Locus applied its TNC technology to high-availability clustering through a project commissioned by Tandem Computers. The resulting UnixWare NonStop Clusters work aimed to provide a single-system image for clustered Unix systems. During that project, Locus was acquired by Platinum Technology Inc. in 1995, and Platinum transferred the team working on NonStop Clusters to Tandem. Later developments in the technology's lineage included the release of related clustering code as open-source software and its porting to Linux under the OpenSSI project, although those later projects were not products of an independent Locus Computing Corporation. The company's history reflects the evolution of enterprise computing from proprietary minicomputers and workstation Unix toward distributed systems, heterogeneous client integration, parallel processing, and high-availability clusters. Locus ultimately ceased to operate as an independent company after its acquisition by Platinum Technology.

Locus Computing Corporation emerged from the academic and engineering work behind the LOCUS distributed operating system at UCLA. Gerald J. Popek, Charles S. Kline, and Gregory I. Thiel founded the company in 1982 with the objective of turning that research into commercial software. The company's core idea was that distributed computers could be presented as a coordinated system, reducing the administrative and operational distinction between individual machines. The company initially developed products for the Unix ecosystem. Its best-known application-compatibility product, Merge, began in the mid-1980s for the AT&T 6300+ computer. The system allowed DOS programs to run within a native Unix SVR2 environment, taking advantage of hardware support for virtualization on the 80286-based machine. As Intel processors evolved, Locus adapted Merge to use the virtual-8086 capabilities of the 80386. The product was subsequently sold for Microport SVR3 and later for SCO Unix and UnixWare. Merge addressed the practical difficulty of adopting Unix while retaining access to DOS and Windows software. In the late 1980s it competed with products such as VP/IX from Interactive Systems Corporation and Phoenix Technologies. Later versions included a specialized socket interface intended to improve networking performance for virtualized Windows environments. Locus also joined Microsoft's WISE program, gaining access to Windows source code and using that relationship to support later versions capable of running packaged Windows applications without requiring a separate copy of Windows in the same manner as earlier releases. Locus's distributed-systems technology was also commercialized through partnerships with larger computer manufacturers. IBM commissioned the company to create AIX versions for the PS/2 and System/370 ranges. The single-system image capabilities derived from LOCUS were incorporated as the AIX Transparent Computing Facility. This work placed Locus technology inside IBM's Unix strategy and demonstrated its applicability beyond a standalone software product. Intel commissioned Locus to create OSF/1 AD, an advanced-development multiprocessor version of OSF/1 for the Intel Paragon massively parallel computer. Supporting process migration and communication among Paragon nodes required Locus to rework its earlier transparent-computing concepts. The resulting Transparent Network Computing technology introduced the VPROC, or virtual process, as a process-management counterpart to the virtual inode concept used in Unix file systems. Locus also built PC-Interface, a LAN-based cross-platform integration toolkit. It connected MS-DOS, Windows, Macintosh, and Unix clients while using Unix as the principal file-system environment. The product supported several Unix families, including AIX, SCO Unix, UnixWare, and Motorola 9000 systems, and represented another attempt to make heterogeneous computing environments operate as an integrated whole. The company's distributed and clustering expertise later supported a project for Tandem Computers. Locus contributed TNC technology to UnixWare NonStop Clusters, a high-availability clustering system intended to provide a unified system image across nodes running SCO UnixWare. Before the project was completed as an independent Locus effort, Platinum Technology acquired Locus in 1995. Platinum transferred the NonStop Clusters team to Tandem. Tandem was later acquired by Compaq, while the UnixWare product lineage moved through SCO and Caldera. Compaq eventually released related NonStop Clusters code as open source and ported it to Linux through the OpenSSI project. Locus therefore occupies a notable place in the history of commercial distributed Unix software. It linked university operating-system research with products for application compatibility, enterprise integration, parallel computing, and high availability. Its corporate life ended with the 1995 acquisition, but concepts and personnel associated with its technology continued to influence later clustering and distributed-system work.

1. 1995Acquisition by Platinum Technology

   Platinum Technology acquired Locus, ending the company's independent corporate existence.

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2. 1984Merge is developed for the AT&T 6300+

   Locus created Merge to run DOS applications under Unix on the AT&T 6300+, establishing one of the company's most recognizable product lines.

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3. 1982Locus Computing Corporation is formed

   Gerald J. Popek, Charles S. Kline, and Gregory I. Thiel founded Locus to commercialize UCLA's LOCUS distributed operating-system technology.

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4. AIX Transparent Computing Facility work

   IBM commissioned Locus to produce AIX versions for the PS/2 and System/370, incorporating Locus single-system image capabilities.

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5. Transparent Network Computing is developed for Intel Paragon

   Locus adapted its distributed-computing technology for OSF/1 AD on Intel's Paragon massively parallel system.

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Locus positioned its technology around making heterogeneous, distributed, or clustered computing environments behave more like unified systems. Its products combined Unix infrastructure with application compatibility, cross-platform file and network integration, parallel processing, and high availability.

• MergeUnix virtualization and application compatibility1984

  Merge was Locus's principal compatibility product. First developed for the AT&T 6300+ in the mid-1980s, it allowed DOS programs to execute within a Unix environment. Later versions used Intel 80386 virtual-8086 support and were sold for Microport SVR3, SCO Unix, and UnixWare. The product was later extended toward Windows application compatibility and included networking-related virtualization technology.

• PC-InterfaceCross-platform LAN integration toolkit

  PC-Interface was a LAN-based integration toolkit connecting Unix systems with MS-DOS, Windows, and Macintosh clients. It used Unix as the central file-system environment and supported multiple Unix platforms, including AIX, SCO Unix, UnixWare, and Motorola 9000 systems.

• AIX Transparent Computing FacilityDistributed Unix operating-system technology

  Produced for IBM's AIX implementations on the PS/2 and System/370 ranges, this technology incorporated Locus's single-system image capabilities into IBM Unix environments.

• OSF/1 ADMassively parallel Unix operating-system software

  OSF/1 AD, meaning Advanced Development, was a multiprocessor version of OSF/1 developed for Intel's Paragon. Locus adapted its distributed-system technology to support communication and process migration among the system's nodes.

• UnixWare NonStop ClustersHigh-availability Unix clustering

  This clustering technology was developed for Tandem Computers on the SCO UnixWare platform. It used Transparent Network Computing concepts to provide a high-availability, single-system image across multiple nodes. The project was affected by Locus's acquisition by Platinum Technology, which transferred the working team to Tandem.

• 1995Locus accepts acquisition by Platinum TechnologyM&A

  Locus had developed distributed Unix, virtualization, and clustering technology but was acquired before its UnixWare NonStop Clusters work reached a fully independent commercial outcome.

  What changed. Platinum Technology Inc. acquired Locus Computing Corporation and transferred the NonStop Clusters team to Tandem Computers.

  Aftermath. Locus ceased operating as an independent company. Related technology later continued through Tandem, Compaq, and subsequent open-source work associated with OpenSSI.

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• 1995Platinum Technology acquires Locus Computing Corporation

  Platinum Technology Inc. acquired Locus, ending its existence as an independent company. The team working on UnixWare NonStop Clusters was subsequently transferred to Tandem Computers.

  M&ALeadership change
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• 1984Locus develops Merge for DOS and Windows compatibility on Unix

  Locus developed Merge as a compatibility and virtualization environment that enabled DOS software to run under Unix and later supported selected Windows applications.

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• 1982Locus Computing Corporation is founded to commercialize LOCUS technology

  Gerald J. Popek, Charles S. Kline, and Gregory I. Thiel formed Locus to bring UCLA-developed distributed operating-system technology to commercial markets.

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• Locus technology is adapted for IBM AIX systems

  IBM commissioned Locus to produce AIX versions for the PS/2 and System/370 lines, incorporating single-system image capabilities under the AIX Transparent Computing Facility designation.

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• Locus develops OSF/1 AD for Intel Paragon

  Locus produced a multiprocessor OSF/1 variant for Intel's Paragon massively parallel system and adapted its technology into Transparent Network Computing.

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1. Locus Computing Corporation