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24-571: A desire to commercialize the technologies developed for LOCUS inspired the creation of the Locus Computing Corporation which went on to include ideas from LOCUS in various products, including OSF/1 AD and, finally, the SCO – Tandem UnixWare NonStop Clusters product. The LOCUS system was created at UCLA between 1980 and 1983, initial implementation was on a cluster of PDP-11 /45s using 1 and 10 megabit ring networks , by 1983

48-495: A copy of Windows. PC-Interface was a popular Lan-based Cross-Platform Integration Toolkit for Unix, providing MS-DOS/Windows/Macintosh and Unix integration using Unix as the file system. It supported AIX, Santa Cruz Operation Inc, UnixWare and Motorola 9000 and many other Unixes and came with one Mac and one MS-DOS/Windows client. Gregory I. Thiel Locus Computing Corporation was formed in 1982 by Gerald J. Popek , Charles S. Kline and Gregory I. Thiel to commercialize

72-510: A particular file system. All accesses to files a file system would need to be coordinated with the appropriate CSS. As with other SSI systems LOCUS sometimes found it necessary to break the illusion of a single system, notably to allow some files to be different on a per-node basis. For example, it was possible to build a LOCUS cluster containing both PDP-11/45 and VAX 750 machines, but instruction sets used were not identical, so two versions of each object program would be needed The solution

96-600: The PS/2 and System/370 ranges. The single-system image capabilities of LOCUS were incorporated under the name of AIX TCF (transparent computing facility). Locus was commissioned by Intel to produce a multiprocessor version of OSF/1 for the Intel Paragon a massively parallel NoRMA (No Remote Memory Access) system. The system was known as OSF/1 AD , where AD stood for "Advanced Development". To allow inter processor process migration and communication between

120-488: The PS/2 and System/370 ranges. The single-system image capabilities of LOCUS were incorporated under the name of AIX TCF (transparent computing facility). Locus was commissioned by Intel to produce a multiprocessor version of OSF/1 for the Intel Paragon a massively parallel NoRMA (No Remote Memory Access) system. The system was known as OSF/1 AD , where AD stood for "Advanced Development". To allow inter processor process migration and communication between

144-467: The 8086 instruction set used by DOS. Merge was later modified to use the virtual 8086 mode provided by Intel 80386 processors. It was sold for Microport SVR3 and later SCO Unix and UnixWare . In the late 1980, the main commercial competitor of Merge was VP/IX developed by Interactive Systems Corporation and Phoenix Technologies . Around 1994, Merge included an innovative socket API that used Intel ring 2 for virtualization. Although this

168-467: The 8086 instruction set used by DOS. Merge was later modified to use the virtual 8086 mode provided by Intel 80386 processors. It was sold for Microport SVR3 and later SCO Unix and UnixWare . In the late 1980, the main commercial competitor of Merge was VP/IX developed by Interactive Systems Corporation and Phoenix Technologies . Around 1994, Merge included an innovative socket API that used Intel ring 2 for virtualization. Although this

192-580: The NonStop Clusters code as open source software , porting it to Linux as the OpenSSI project. Merge was a system developed by Locus in late 1984 for the AT&;T 6300+ computer, which allowed DOS (and hence DOS applications) to be run under the native UNIX SVR2 operating system. The 6300+ used an Intel 80286 processor and included special-purpose circuitry to allow virtualization of

216-406: The NonStop Clusters code as open source software , porting it to Linux as the OpenSSI project. Merge was a system developed by Locus in late 1984 for the AT&T 6300+ computer, which allowed DOS (and hence DOS applications) to be run under the native UNIX SVR2 operating system. The 6300+ used an Intel 80286 processor and included special-purpose circuitry to allow virtualization of

240-408: The course of the project Locus was acquired by Platinum Technology Inc, who transferred the team working on NonStop Clusters to Tandem. Tandem were later bought by Compaq . The UnixWare product was acquired from SCO by Caldera Systems / Caldera International , who discontinued commercialization of the NonStop Clusters product in favor of the simpler Reliant HA system. Compaq then decided to release

264-408: The course of the project Locus was acquired by Platinum Technology Inc, who transferred the team working on NonStop Clusters to Tandem. Tandem were later bought by Compaq . The UnixWare product was acquired from SCO by Caldera Systems / Caldera International , who discontinued commercialization of the NonStop Clusters product in favor of the simpler Reliant HA system. Compaq then decided to release

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288-421: The data of files could be stored on more than one node and LOCUS would keep the various copies up to date. This provided particularly good access times for files that were read more often than they were written, the normal case for directories for example. In order to ensure that all access was made to the most recent version of any file LOCUS would nominate one node as the "current synchronization site" (CSS) for

312-730: The individual nodes of the Paragon system they re-worked the TCF technology from LOCUS as Transparent Network Computing, or TNC, inventing the concept of the VPROC (virtual process) an analogy of the VNODE (virtual inode) from the SunOS virtual file system . Locus was commissioned by Tandem Computers to include their TNC technology in a highly available single-system image clustering system based on SCO UnixWare , UnixWare NonStop Clusters . During

336-471: The individual nodes of the Paragon system they re-worked the TCF technology from LOCUS as Transparent Network Computing, or TNC, inventing the concept of the VPROC (virtual process) an analogy of the VNODE (virtual inode) from the SunOS virtual file system . Locus was commissioned by Tandem Computers to include their TNC technology in a highly available single-system image clustering system based on SCO UnixWare , UnixWare NonStop Clusters . During

360-445: The new image. Processes could use pipes for inter node communication, including named pipes , The LOCUS system was designed to be able to cope with network partitioning - one or more nodes becoming disconnected from the rest of the system. As the file system was replicated the disconnected nodes could continue to access files. When the nodes were reconnected any files modified by the disconnected nodes would be merged back into

384-418: The process would be run. LOCUS was designed to work with heterogeneous nodes, (e.g., a mix of VAX 750s and PDP 11/45s) and could decide to execute a process on a different node if it needed a particular instruction set. As an optimization a run call was added which was equivalent to a combined fork and exec, thus avoiding the overhead of copying the process memory image to another node before overwriting it by

408-412: The system was running on 17 VAX-11/750s using a 10 megabit Ethernet . The system was Unix compatible and provided both a single root view of the file system and a unified process space across all nodes. The development of LOCUS was supported by an ARPA research contract, DSS-MDA-903-82-C-0189. In order to allow reliable and rapid access to the cluster wide filesystem LOCUS used replication ,

432-494: The system would find that /bin/who was actually a hidden directory and run the command /bin/who/45 . Another user on a VAX node who typed /bin/who would run the command /bin/who/vax . LOCUS provided remote access to I/O devices. LOCUS provided a single process space. Processes could be created on any node on the system. Both the Unix fork and exec calls would examine an advice list which determined on which node

456-404: The system. For some file types (for example mailboxes) the system would perform the merge automatically, for others the user would be informed (by mail) and tools were provided to allow access to the different versions of the file. Locus Computing Corporation Locus Computing Corporation was formed in 1982 by Gerald J. Popek , Charles S. Kline and Gregory I. Thiel to commercialize

480-586: The technologies developed for the LOCUS distributed operating system at UCLA . Locus was notable for commercializing single-system image software and producing the Merge package which allowed the use of DOS and Windows 3.1 software on Unix systems. Locus was acquired by Platinum Technology Inc in 1995. Locus was commissioned by IBM to produce a version of the AIX UNIX based operating system for

504-429: The technologies developed for the LOCUS distributed operating system at UCLA . Locus was notable for commercializing single-system image software and producing the Merge package which allowed the use of DOS and Windows 3.1 software on Unix systems. Locus was acquired by Platinum Technology Inc in 1995. Locus was commissioned by IBM to produce a version of the AIX UNIX based operating system for

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528-489: Was the fastest network access of any Windows virtualization system then on the market, it did not increase sales enough to make Locus independent. This socket API was designed and developed by Real Time, Inc. of Santa Barbara. Locus eventually joined the Microsoft WISE program which gave them access to Windows source code, which allowed later versions of Merge to run Windows Shrink wrapped applications without

552-426: Was the fastest network access of any Windows virtualization system then on the market, it did not increase sales enough to make Locus independent. This socket API was designed and developed by Real Time, Inc. of Santa Barbara. Locus eventually joined the Microsoft WISE program which gave them access to Windows source code, which allowed later versions of Merge to run Windows Shrink wrapped applications without

576-468: Was to replace the files that needed to be different on a per node basis by special hidden directories. These directories would then contain the different versions of the file. When a user accessed one of these hidden directories the system would check the user's context and open the appropriate file. For example, if the user was running on one of the PDP-11/45's and typed the command /bin/who then

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