Merge was originally developed to run DOS under UNIX System V Release 2 on an AT&T 6300 Plus personal computer. Development of the virtual machine began in late 1984, and AT&T announced the availability of the machine on 9 October 1985,[1] referring to the bundled Merge software as Simultask.[2] (The PC 6300 Plus shipped with MS-DOS in 1985 though, because its Unix System V distribution was not ready until the end of March 1986.)[3] Merge was developed by engineers at Locus Computing Corporation, with collaboration from AT&T hardware and software engineers, particularly on aspects of the system that were specific to the 6300 Plus (in contrast to a standard IBM PC/AT).
The AT&T 6300 Plus contained an Intel 80286 processor, which did not include the support for 8086 virtual machines (virtual 8086 mode) found in the 80386 and later processors in the x86 family. On the 80286, the DOS program had to run in real mode. The 6300 Plus was designed with special hardware on the bus that would suppress and capture bus cycles from the DOS program if they were directed toward addresses not assigned for direct access by the DOS virtual machine.[4] Various system registers, such as the programmable interrupt controller (PIC), and the video controller, had to be emulated in software for the DOS process, and a watchdog timer was implemented to recover from DOS programs that would clear the interrupt flag and then hang for too long. The hardware used the non-maskable interrupt (NMI) to take control back to the emulation code.[5]
Later, Merge was enhanced to make use of the virtual 8086 mode provided by the 80386 processor; that version was offered with Microport SVR3 starting in 1987,[citation needed] and subsequently with SCO Unix. There was also a Merge/286 version that ran on an unmodified PC/AT (without any special I/O trapping hardware); it ran as long as the PC program was reasonably well-behaved, though a malicious or crashing program could take the unprotected UNIX kernel down on those machines. Even so, the notoriously ill-behaved Microsoft Flight Simulator would run on the PC/AT simultaneously with Unix.[citation needed] These later versions were marketed directly by Locus as well as through some OEM and ISV channels. A product-evaluation version with user manual appeared in January 1987, with retail Version 1.0 of Merge/386 shipping in October of that year.
Locus eventually joined the MicrosoftWISE[9] program which gave them access to Microsoft Windows source code, which allowed later versions of Merge to run Windows shrink wrapped applications without a copy of Windows.[10]
On 12 April 1995, Platinum Technology announced an agreement in principle to acquire Locus Computing Corporation for approximately US$33 million, about 1/4 of which was attributed to the Merge technology and product.[citation needed] The acquisition went through, and Platinum went on to develop the SCO Merge 4 version with Windows 95 support, which was released in 1998.[11]
The Merge technology was bought by a company called DASCOM in 1999, which was in turn bought by IBM. A company called TreLOS was spun off in 2000 that continued the development of the virtual machine software and created Win4Lin. TreLOS later merged into NeTraverse, Inc.
^Petrosky, Mary (1985-10-14). "6300 Plus Launched By AT&T". InfoWorld. Vol. 7, no. 41. Popular Computing, Inc. pp. 1, 8. ISSN 0199-6649. from the original on 2020-02-10. Retrieved 2020-02-10.
^Welch, Mark J. (1986-06-30). "Another Unix Project to Run DOS on 80386". InfoWorld. Vol. 8, no. 26. Popular Computing, Inc. p. 3. ISSN 0199-6649. from the original on 2020-02-10. Retrieved 2020-02-10. […] Locus previously developed Merge 286, now used by AT&T's Simultask program to run one MS-DOS program under Unix on the 80286-based 6300 Plus, according to Judi Uttal, director of marketing for Locus. […]
^"Even without Unix, Byers Like AT&T's PC 6300". InfoWorld. News. Vol. 8, no. 2. Morristown, NJ, USA: Popular Computing, Inc. 1986-01-13. p. 13. ISSN 0199-6649. from the original on 2020-02-10. Retrieved 2020-02-09.
^Prestinario, Jerry A. (1986-12-15). "Simultask Response". InfoWorld. Review Responses. Vol. 8, no. 50. Popular Computing, Inc. p. 71. ISSN 0199-6649. from the original on 2020-02-10. Retrieved 2020-02-10. […] A recent Review Response stated that no special hardware is required to run Simultask [and therefore it could run on any 80286 computer]. Every PC 6300 Plus comes standard with special circuitry on the motherboard. This hardware is activated with Simultask to prevent programs from interfering with one another when they are running simultaneously. This is necessary because many MS-DOS programs have complete control of the hardware. Simultask uses this circuitry to ensure that, no matter what one program does, other programs that are running simultaneously will not be affected. Other computers can't provide this assurance. […]
^"U.S. Patent: Dual Operating System Computer". from the original on 2020-02-10. Retrieved 2020-02-10.
^Rosen, Kenneth H.; Rosinski, Richard R.; Farber, James M. (1990). UNIX System V release 4: an introduction for new and experienced users. Berkeley, USA: Osborne McGraw-Hill. p. 934. ISBN978-0-07-881552-2.
^. January 1995. Archived from the original on 2008-03-30. Retrieved 2009-11-26.
^. 1995-05-09. Archived from the original on 2010-12-04. Retrieved 2009-11-26.
^Magee, Mike (1998-02-19). . Archived from the original on 2014-02-22.
merge, software, other, types, merge, performed, software, merge, computer, science, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, article, includes, list, gene. For other types of merge performed by software see Merge Computer science This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article includes a list of general references but it lacks sufficient corresponding inline citations Please help to improve this article by introducing more precise citations August 2012 Learn how and when to remove this message This article needs to be updated Please help update this article to reflect recent events or newly available information August 2012 Learn how and when to remove this message Merge is a software system which allows a user to run DOS Windows 3 1 on SCO UNIX in an 8086 virtual machine MergeDeveloper s Locus Computing CorporationInitial release9 October 1985 38 years ago 1985 10 09 Operating systemSCO UNIXPlatformIntel 8086 Contents 1 History 2 See also 3 References 4 External linksHistory editMerge was originally developed to run DOS under UNIX System V Release 2 on an AT amp T 6300 Plus personal computer Development of the virtual machine began in late 1984 and AT amp T announced the availability of the machine on 9 October 1985 1 referring to the bundled Merge software as Simultask 2 The PC 6300 Plus shipped with MS DOS in 1985 though because its Unix System V distribution was not ready until the end of March 1986 3 Merge was developed by engineers at Locus Computing Corporation with collaboration from AT amp T hardware and software engineers particularly on aspects of the system that were specific to the 6300 Plus in contrast to a standard IBM PC AT The AT amp T 6300 Plus contained an Intel 80286 processor which did not include the support for 8086 virtual machines virtual 8086 mode found in the 80386 and later processors in the x86 family On the 80286 the DOS program had to run in real mode The 6300 Plus was designed with special hardware on the bus that would suppress and capture bus cycles from the DOS program if they were directed toward addresses not assigned for direct access by the DOS virtual machine 4 Various system registers such as the programmable interrupt controller PIC and the video controller had to be emulated in software for the DOS process and a watchdog timer was implemented to recover from DOS programs that would clear the interrupt flag and then hang for too long The hardware used the non maskable interrupt NMI to take control back to the emulation code 5 Later Merge was enhanced to make use of the virtual 8086 mode provided by the 80386 processor that version was offered with Microport SVR3 starting in 1987 citation needed and subsequently with SCO Unix There was also a Merge 286 version that ran on an unmodified PC AT without any special I O trapping hardware it ran as long as the PC program was reasonably well behaved though a malicious or crashing program could take the unprotected UNIX kernel down on those machines Even so the notoriously ill behaved Microsoft Flight Simulator would run on the PC AT simultaneously with Unix citation needed These later versions were marketed directly by Locus as well as through some OEM and ISV channels A product evaluation version with user manual appeared in January 1987 with retail Version 1 0 of Merge 386 shipping in October of that year In the late 1980s the main commercial competitor of Merge was VP IX developed by Interactive Systems Corporation and Phoenix Technologies 6 AT amp T s Simultask 2 0 was based on VP IX 7 8 In 1992 Univel UnixWare 1 0 Personal Edition came with DOS Merge 3 0 and Novell s DR DOS 6 0 Locus eventually joined the Microsoft WISE 9 program which gave them access to Microsoft Windows source code which allowed later versions of Merge to run Windows shrink wrapped applications without a copy of Windows 10 On 12 April 1995 Platinum Technology announced an agreement in principle to acquire Locus Computing Corporation for approximately US 33 million about 1 4 of which was attributed to the Merge technology and product citation needed The acquisition went through and Platinum went on to develop the SCO Merge 4 version with Windows 95 support which was released in 1998 11 The Merge technology was bought by a company called DASCOM in 1999 which was in turn bought by IBM A company called TreLOS was spun off in 2000 that continued the development of the virtual machine software and created Win4Lin TreLOS later merged into NeTraverse Inc The SCO Group distributes NeTraverse Merge 5 3 which supports their current products SCO OpenServer 5 x and UnixWare 7 12 See also editPopek and Goldberg virtualization requirements Dr Popek was one of the founders of Locus Windows Interface Source Environment WISE References edit Petrosky Mary 1985 10 14 6300 Plus Launched By AT amp T InfoWorld Vol 7 no 41 Popular Computing Inc pp 1 8 ISSN 0199 6649 Archived from the original on 2020 02 10 Retrieved 2020 02 10 Welch Mark J 1986 06 30 Another Unix Project to Run DOS on 80386 InfoWorld Vol 8 no 26 Popular Computing Inc p 3 ISSN 0199 6649 Archived from the original on 2020 02 10 Retrieved 2020 02 10 Locus previously developed Merge 286 now used by AT amp T s Simultask program to run one MS DOS program under Unix on the 80286 based 6300 Plus according to Judi Uttal director of marketing for Locus Even without Unix Byers Like AT amp T s PC 6300 InfoWorld News Vol 8 no 2 Morristown NJ USA Popular Computing Inc 1986 01 13 p 13 ISSN 0199 6649 Archived from the original on 2020 02 10 Retrieved 2020 02 09 Prestinario Jerry A 1986 12 15 Simultask Response InfoWorld Review Responses Vol 8 no 50 Popular Computing Inc p 71 ISSN 0199 6649 Archived from the original on 2020 02 10 Retrieved 2020 02 10 A recent Review Response stated that no special hardware is required to run Simultask and therefore it could run on any 80286 computer Every PC 6300 Plus comes standard with special circuitry on the motherboard This hardware is activated with Simultask to prevent programs from interfering with one another when they are running simultaneously This is necessary because many MS DOS programs have complete control of the hardware Simultask uses this circuitry to ensure that no matter what one program does other programs that are running simultaneously will not be affected Other computers can t provide this assurance U S Patent Dual Operating System Computer Archived from the original on 2020 02 10 Retrieved 2020 02 10 Computerworld Computerworld IDG Enterprise 1987 10 26 pp 81 ISSN 0010 4841 Retrieved 2020 02 09 PC Mag PC Magazine Ziff Davis Inc 1989 04 11 pp 152 ISSN 0888 8507 Retrieved 2020 02 09 Rosen Kenneth H Rosinski Richard R Farber James M 1990 UNIX System V release 4 an introduction for new and experienced users Berkeley USA Osborne McGraw Hill p 934 ISBN 978 0 07 881552 2 Windows Interface Source Environment WISE January 1995 Archived from the original on 2008 03 30 Retrieved 2009 11 26 Locus announces availability of Merge 3 2 for SCO OpenServer Release 5 1995 05 09 Archived from the original on 2010 12 04 Retrieved 2009 11 26 Magee Mike 1998 02 19 SCO runs Windows 95 apps on Unix Archived from the original on 2014 02 22 Xinuos Inc Products Merge Merge 5 www sco com Retrieved 2022 04 04 External links edit MergePro for SCO OpenServer and UnixWare O Gara Maureen 2003 12 20 Can CA save Linux from the great Satan SCO Computerworld New Zealand IDG Communications ISSN 0113 1494 CMPWNZ Archived from the original on 2016 03 03 Retrieved from https en wikipedia org w index php title Merge software amp oldid 1187051496 3 0, wikipedia, wiki, book, books, library,
