Editing VAX (section)

== VAX-based systems ==
{{See also|List of VAX computers}}
[[File:SPEC-1 VAX 05.jpg|thumb|The SPEC-1 VAX, a VAX 11/780 used for [[benchmark (computing)|benchmarking]], showing internals]]

The first VAX-based system was the [[VAX-11/780]], a member of the [[VAX-11]] family. The high-end [[VAX 8600]] replaced the VAX-11/780 in October 1984 and was joined by the entry-level [[MicroVAX]] minicomputers and the [[VAXstation]] workstations in the mid-1980s. The MicroVAX was superseded by the [[VAX 4000]], the VAX 8000 was superseded by the [[VAX 6000]] in the late 1980s and the mainframe-class [[VAX 9000]] was introduced. In the early 1990s, the [[Fault tolerance|fault-tolerant]] [[VAXft]] was introduced, as were the [[DEC Alpha|Alpha]] compatible [[VAX 7000/10000]]. A variant of various VAX-based systems were sold as the [[VAXserver]].

=== SIMACS ===
''[[System Industries]]'' developed an ability to give more than one DEC CPU, but not at the same time, write access to a shared disk. They implemented an enhancement named [[SIMACS]] (simultaneous machine access),<ref>{{cite web |url=http://www.atnf.csiro.au/observers/memos/d95f80~1.pdf |title=Computing Requirements for AT Software Development |last1=Wand |first1=R. |last2=Kesteven |first2=M. |last3=Rayner |first3=P. |date=February 24, 1984}}</ref><ref name=SIMACS.HC84>{{cite magazine |last1=Joshi |first1=Prem |last2=Delacroix |first2=Jacques |date=September 1984 |title=New Flexibility For Multiple VAX/VMS |magazine=[[HARDCOPY]] |pages=64–68}}</ref> which allowed their special disk controller to set a [[Semaphore (computing)|semaphore flag]] for disk access, allowing multiple WRITES to the same files; the disk is shared by multiple DEC systems. ''SIMACS'' also existed on PDP-11 [[RSTS/E|RSTS]] systems.

=== Canceled systems ===
Canceled systems include the ''BVAX'', a high-end [[emitter-coupled logic]] (ECL) based VAX, and two other ECL-based VAX models: ''Argonaut'' and ''Raven''.<ref>{{cite web |title=Who are the Computer Architects? |url=http://www.cs.clemson.edu/~mark/architects.html |author=Mark Smotherman |date=July 19, 2008 |access-date=September 30, 2008}}</ref> Raven was canceled in 1990.<ref>{{cite web |url=http://simh.trailing-edge.com/semi/raven.html |website=Computer History and Simulation |title=Raven |last=Supnik |first=Bob |date=2007 |access-date=March 1, 2019}}</ref> A VAX named ''Gemini'' was also canceled, which was a fall-back in case the LSI-based ''Scorpio'' failed. It never shipped.

=== Clones ===
A number of VAX clones, both authorized and unauthorized, were produced. Examples include:

* [[Systime Computers Ltd]] of the United Kingdom produced clones of early VAX models such as the Systime 8750 (equivalent to the VAX 11/750).<ref>{{cite web |url=http://www.chilton-computing.org.uk/inf/literature/inf_reports/p001.htm |title=RAL Informatics Report 1984-85 |access-date=October 15, 2007}}</ref>
* Norden Systems produced the ruggedized, Military-specification MIL VAX series.<ref name="vaxvmsat20"/>
* The Hungarian Central Research Institute for Physics (KFKI) produced a series of clones of early VAX models, the TPA-11/540, 560 and 580.<ref>{{cite web |url=http://hampage.hu/tpa/e_index.html |title=The TPA story |access-date=October 15, 2007}}</ref>
* The SM 52/12<ref>{{cite journal |last1=Dujnic |first1=J. |last2=Fristacky |first2=N. |last3=Molnar |first3=L. |last4=Plander |first4=I. |last5=Rovan |first5=B. |year=1999 |title=On the history of computer science, computer engineering, and computer technology development in Slovakia |journal=IEEE Annals of the History of Computing |volume=21 |issue=3 |pages=38–48 |doi=10.1109/85.778981}}</ref> from [[Czechoslovakia]], developed at VUVT [[Žilina]] (today [[Slovakia]]) and produced from 1986 at ZVT [[Banská Bystrica]] (today [[Slovakia]]).
* The East German [[VEB Robotron]] [[Robotron K&nbsp;1840|K&nbsp;1840]] (SM 1710) is a clone of the VAX-11/780 and [[Robotron K 1820]] (SM 1720) is a copy of the MicroVAX II.
* The ''SM-1700'' is a Soviet clone of the VAX-11/730, ''SM-1702'' was a clone of MicroVAX II and ''SM-1705'' was a clone of VAX-11/785.<ref>{{cite journal|author1=Laimutis Telksnys|author2=Antanas Zilinskas|title=Computers in Lithuania|journal=IEEE Annals of the History of Computing|volume=21|number=3|pages=31–37|date=July 1999|url=http://www.computer.org/csdl/mags/an/1999/03/00778980.pdf|doi=10.1109/85.778980|s2cid=16240778}}</ref> These systems ran a variety of clone operating systems - [[DEMOS]] (based on BSD Unix), [[OpenVMS#Influence|MOS VP]] (based on VAX/VMS) or MOS VP RV (based on VAXELN).<ref>{{cite journal|url=http://www.swsys.ru/index.php?page=article&id=1480#|journal=Software Systems Journal|volume=1988|issue=3|title=Basic software for 32-bit SM computer models|author1=Prokhorov N.L.|author2=Gorskiy V.E.|language=Russian|access-date=2021-09-15}}</ref>
* The NCI-2780 Super-mini, also sold as Taiji-2780, is a clone of the VAX-11/780 developed by North China Institute of Computing Technology in Beijing.<ref>{{cite book|url=https://books.google.com/books?id=E0LoOH-GqagC&q=%22NCI-2780%22&pg=PA96|title=Technology transfer to China|author=[[U.S. Congress]], [[Office of Technology Assessment]]|publisher=[[U.S. Government Printing Office]]|date=July 1987|page=96|isbn=9781428922914|id=OTA-USC-340}}</ref><ref>{{cite book|chapter-url=https://books.google.com/books?id=u7HItO03SlwC&q=%22NCI-2780%22&pg=PA244|title=Space Commercialization: Launch Vehicles and Programs|editor1=F. Sharokhi|editor2=J. S. Greenberg|editor3=T. Al-Saud|chapter=Satellite Launch and TT&C Systems of China and Their Roles in International Cooperation|author1=Xia Nanyin|author2=Chan Laixing|year=1990|page=244|publisher=[[American Institute of Aeronautics and Astronautics]]|isbn=0-930403-75-4}}</ref>