Editing ES EVM (section)

== Development ==
In 1966, the Soviet economists suggested creating a unified series of mutually compatible computers. Due to the success of the IBM System/360 in the United States, the economic planners decided to use the IBM design, although some prominent Soviet computer scientists had criticized the idea and suggested instead choosing one of the Soviet indigenous designs, such as [[BESM]] or [[Minsk family of computers|Minsk]]. The first works on the cloning began in 1968; production started in 1972. In addition, after 1968, other Comecon countries joined the project.

With the exception of only a few hardware pieces, the ES EVM machines were recognized in the Western countries as independently designed, based on legitimate Soviet patents.<ref>{{Cite web|url=http://computer-museum.ru/histussr/es_hist.htm|title = Исторический обзор семейства ЕС ЭВМ}}</ref> Unlike the hardware, which was quite original, mostly created by [[reverse engineering]], much of the software was based on slightly modified and localized IBM code. In 1974–1976, IBM had contacted the Soviet authorities and expressed interest in ES EVM development; however, after the Soviet Army entered [[Afghanistan]], in 1979, all contacts between IBM and ES developers were interrupted, due to the U.S. embargo on technological cooperation with the USSR.

Due to the [[CoCom]] restrictions, much of the software localization was done through [[disassembler|disassembling]] the IBM software, with some minimal modification. The most common [[operating system]] was [[OS ES]] ({{langx|ru|ОС ЕС}}), a modified version of [[OS/360]]; the later versions of OS ES were very original and different from the IBM OSes, but they also included a lot of original IBM code. There were even anecdotal rumors among the Soviet programmers, that this supposedly Soviet operating system contained some [[Easter egg (software)|secret command]] which outputs the [[The Star-Spangled Banner|American national anthem]]. Today some of the Russian institutions that worked on ES EVM are cooperating with IBM to continue legacy support for both actual IBM mainframes and the ES EVM systems.{{Update inline|date=January 2023|reason=Presumably, any ongoing cooperation between IBM and Russia regarding mainframes has ceased due to the 2022 Ukraine war sanctions}}

ES EVM machines were developed in [[Moscow]], at the [[Scientific Research Center for Electronic Computer Machinery]] (NITsEVT); in [[Yerevan]], [[Armenia]], at [[Yerevan Computer Research and Development Institute]]; and later in [[Minsk]], at the [[Scientific Research Institute of Electronic Computer Machines]] (NIIEVM); and in [[Penza]], at the [[Penza Scientific Research Institute of Computer Machinery]]. They were manufactured in Minsk, at the [[Minsk Production Group for Computing Machinery]] (MPOVT); and in Penza, at the [[Penza Electronic Computer Factory]]. Some models had been also produced in other countries of the [[Eastern Bloc]], such as [[Bulgaria]], [[Hungary]], [[Poland]], [[Czechoslovakia]], [[Romania]], and [[East Germany]]; some peripheral devices were also produced in [[Cuba]]. The former German chancellor [[Angela Merkel]], used one of East Germany's ES EVM computers in 1986 for her PhD dissertation.<ref>{{Cite web|title=Angela Merkel - Harvard University Commencement Address (English)|url=https://www.americanrhetoric.com/speeches/angelamerkelharvardcommencementenglish.htm|access-date=2020-09-15|website=www.americanrhetoric.com}}</ref>

ES EVM computers were assigned to four subseries or generations ({{langx|ru|ряд|translit=ryad}}), known as Ryad 1, Ryad 2, Ryad 3 and Ryad 4, this nomenclature gave rise to the common name for the whole project.