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Stored-program computer
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<h2 id="description">Description</h2> <p>In principle, stored-program computers have been designed with various architectural characteristics. A computer with a <a href="/facts/Von_Neumann_architecture/te0yulFa">von Neumann architecture</a> stores program data and instruction data in the same memory, while a computer with a <a href="/facts/Harvard_architecture/n9YMly7Q">Harvard architecture</a> has separate memories for storing program and data.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> However, the term <i>stored-program computer</i> is sometimes used as a synonym for the von Neumann architecture.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a><a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> <a href="/facts/Jack_Copeland/KhP2twFs">Jack Copeland</a> considers that it is "historically inappropriate, to refer to electronic stored-program digital computers as 'von Neumann machines'".<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> Hennessy and Patterson wrote that the early Harvard machines were regarded as "reactionary by the advocates of stored-program computers".<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <h2 id="history">History</h2> <p>The concept of the stored-program computer can be traced back to the 1936 theoretical concept of a <a href="/facts/Universal_Turing_machine/2klpb1qQ">universal Turing machine</a>.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> Von Neumann was aware of this paper, and he impressed it on his collaborators.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p><p>Many early computers, such as the <a href="/facts/Atanasoff%E2%80%93Berry_computer/JJg9kmv3">Atanasoff–Berry computer</a>, were not reprogrammable. They executed a single hardwired program. As there were no program instructions, no program storage was necessary. Other computers, though programmable, stored their programs on <a href="/facts/Punched_tape/8HI7dThI">punched tape</a>, which was physically fed into the system as needed, as was the case for the <a href="/facts/Zuse_Z3/JNPXGqDp">Zuse Z3</a> and the <a href="/facts/Harvard_Mark_I/0d0yAVjb">Harvard Mark I</a>, or were only programmable by physical manipulation of switches and plugs, as was the case for the <a href="/facts/Colossus_computer/pbkHLPwp">Colossus computer</a>. </p><p>In 1936, <a href="/facts/Konrad_Zuse/yrvbaEg3">Konrad Zuse</a> anticipated in two patent applications that machine instructions could be stored in the same storage used for data.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> </p><p>In 1948, the <a href="/facts/Manchester_Baby/tpkAwQnc">Manchester Baby</a>, built at <a href="/facts/University_of_Manchester/PwJzEj8h">University of Manchester</a>,<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> is generally recognized as world's first electronic computer that ran a stored program—an event on 21 June 1948.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a><a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a> However the Baby was not regarded as a full-fledged computer, but more a <a href="/facts/Proof_of_concept/1YzUH8LJ">proof of concept</a> predecessor to the <a href="/facts/Manchester_Mark_1/S8wpt6U5">Manchester Mark 1</a> computer, which was first put to research work in April 1949. On 6 May 1949 the <a href="/facts/EDSAC/nyK6xJ7B">EDSAC</a> in Cambridge ran its first program, making it another electronic digital stored-program computer.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> It is sometimes claimed that the <a href="/facts/IBM_SSEC/hofkk46I">IBM SSEC</a>, operational in January 1948, was the first stored-program computer;<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> this claim is controversial, not least because of the hierarchical memory system of the SSEC, and because some aspects of its operations, like access to relays or tape drives, were determined by plugging.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> The first stored-program computer to be built in continental Europe was the <a href="/facts/MESM/aUodDQRK">MESM</a>, completed in the <a href="/facts/Computer_systems_in_the_Soviet_Union/He6w7j97">Soviet Union</a> in 1950.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> </p> <h3>The first stored-program computers</h3> <p>Several computers could be considered the first stored-program computer, depending on the criteria.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> </p> <ul><li><a href="/facts/IBM_SSEC/hofkk46I">IBM SSEC</a>, was designed in late 1944 and became operational in January 1948 but was <a href="/facts/Electromechanical/0D5gkXko">electromechanical</a><a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a></li> <li>In April 1948, modifications were completed to <a href="/facts/ENIAC/EcfmM1Y0">ENIAC</a> to function as a stored-program computer, with the program stored by setting dials in its function tables, which could store 3,600 decimal digits for instructions. It ran its first stored program on 12 April 1948 and its first production program on 17 April<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a><a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> This claim is disputed by some computer historians.<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a></li> <li><a href="/facts/APEXC/DpwJ3nKH">ARC2</a>, a relay machine developed by <a href="/facts/Andrew_Donald_Booth/5Rnt1oKI">Andrew Booth</a> and <a href="/facts/Kathleen_Booth/EqozPTAr">Kathleen Booth</a> at <a href="/facts/Birkbeck,_University_of_London/0xSxtEUk">Birkbeck, University of London</a>, officially came online on 12 May 1948.<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> It featured the first <a href="/facts/Drum_memory/yul0r8nG">rotating drum storage device</a>.<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a><a class="footnote-ref" id="fnref:28" href="#fn:28"><sup>28</sup></a></li> <li><a href="/facts/Manchester_Baby/tpkAwQnc">Manchester Baby</a>, a developmental, fully electronic computer that successfully ran a stored program on 21 June 1948. It was subsequently developed into the <a href="/facts/Manchester_Mark_1/S8wpt6U5">Manchester Mark 1</a>, which ran its first program in early April 1949.</li> <li><a href="/facts/Electronic_Delay_Storage_Automatic_Calculator/nyK6xJ7B">Electronic Delay Storage Automatic Calculator</a>, EDSAC, which ran its first programs on 6 May 1949, and became a full-scale operational computer that served a user community beyond its developers.</li> <li><a href="/facts/EDVAC/6DHxuu2d">EDVAC</a>, conceived in June 1945 in <i><a href="/facts/First_Draft_of_a_Report_on_the_EDVAC/CQBHmxoe">First Draft of a Report on the EDVAC</a></i>, but not delivered until August 1949. It began actual operation (on a limited basis) in 1951.</li> <li><a href="/facts/BINAC/HcSpFW5J">BINAC</a>, delivered to a customer on 22 August 1949. It worked at the factory but there is disagreement about whether or not it worked satisfactorily after being delivered. If it had been finished at the projected time, it would have been the first stored-program computer in the world. It was the first stored-program computer in the U.S.<a class="footnote-ref" id="fnref:29" href="#fn:29"><sup>29</sup></a></li> <li>In 1951, the <a href="/facts/Ferranti_Mark_1/Q6hK6sI0">Ferranti Mark 1</a>, a cleaned-up version of the Manchester Mark 1, became the first commercially available electronic digital computer.</li> <li>The <a href="/facts/Bull_Gamma_3/aLaNFovc">Bull Gamma 3</a> (1952) and <a href="/facts/IBM_650/l5mCAMIF">IBM 650</a> (1953) were the first mass produced commercial computers, respectively selling about 1200 and 2000 units.</li> <li><a href="/facts/Manchester_University_Transistor_Computer/VUeMAx0c">Manchester University Transistor Computer</a>, is generally regarded as the first transistor-based stored-program computer having become operational in November 1953.<a class="footnote-ref" id="fnref:30" href="#fn:30"><sup>30</sup></a><a class="footnote-ref" id="fnref:31" href="#fn:31"><sup>31</sup></a></li></ul> <h3>Telecommunication</h3> <p>The concept of using a stored-program computer for switching of telecommunication circuits is called <a href="/facts/Stored_program_control/FXtRRPlr">stored program control</a> (SPC). It was instrumental to the development of the first <a href="/facts/Electronic_switching_system/rqHUmBML">electronic switching systems</a> by <a href="/facts/American_Telephone_and_Telegraph/BfsX7eX2">American Telephone and Telegraph</a> (AT&T) in the <a href="/facts/Bell_System/GspEoeEF">Bell System</a>,<a class="footnote-ref" id="fnref:32" href="#fn:32"><sup>32</sup></a> a development that started in earnest by c. 1954 with initial concept designs by <a href="/facts/Erna_Schneider_Hoover/74d3kqxs">Erna Schneider Hoover</a> at <a href="/facts/Bell_Labs/fKP5Gk0H">Bell Labs</a>. The first of such systems was installed on a trial basis in <a href="/facts/Morris,_Illinois/JMY4L5Qk">Morris, Illinois</a> in 1960.<a class="footnote-ref" id="fnref:33" href="#fn:33"><sup>33</sup></a> The storage medium for the program instructions was the <a href="/facts/Flying-spot_store/t6CjGEHW">flying-spot store</a>, a <a href="/facts/Photographic_plate/LbTmHKJb">photographic plate</a> read by an optical scanner that had a speed of about one microsecond access time.<a class="footnote-ref" id="fnref:34" href="#fn:34"><sup>34</sup></a> For temporary data, the system used a barrier-grid electrostatic <a href="/facts/Storage_tube/42gU6bXG">storage tube</a>. </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Stored_program_control/FXtRRPlr">Stored program control</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Allison, Joanne (1997), Stored-program Computers, archived from the original on 27 September 2011, retrieved 24 August 2011 <a href="https://web.archive.org/web/20110927012816/http://www.computer50.org/mark1/stored.html" target="_blank">https://web.archive.org/web/20110927012816/http://www.computer50.org/mark1/stored.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>William F. Gilreath; Phillip A. Laplante (2003). Computer Architecture: A Minimalist Perspective. Springer. p. 24. ISBN 978-1-4020-7416-5. <a href="978-1-4020-7416-5" target="_blank">978-1-4020-7416-5</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Edwin D. Reilly (2003). Milestones in computer science and information technology. Greenwood Publishing Group. p. 245. ISBN 978-1-57356-521-9. <a href="978-1-57356-521-9" target="_blank">978-1-57356-521-9</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Murdocca, Miles J.; Vincent P. Heuring (2000). Principles of Computer Architecture. Prentice-Hall. p. 5. ISBN 0-201-43664-7. <a href="0-201-43664-7" target="_blank">0-201-43664-7</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Daniel Page (2009). A Practical Introduction to Computer Architecture. Springer. p. 148. ISBN 978-1-84882-255-9. <a href="978-1-84882-255-9" target="_blank">978-1-84882-255-9</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Mark Balch (2003). Complete digital design: a comprehensive guide to digital electronics and computer system architecture. McGraw-Hill Professional. p. 149. ISBN 978-0-07-140927-8. Retrieved 18 May 2011. <a href="978-0-07-140927-8" target="_blank">978-0-07-140927-8</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Daniel Page (2009). A Practical Introduction to Computer Architecture. Springer. p. 153. ISBN 978-1-84882-255-9. <a href="978-1-84882-255-9" target="_blank">978-1-84882-255-9</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Ivor Grattan-Guinness (2003). Companion encyclopedia of the history and philosophy of the mathematical sciences. JHU Press. p. 705. 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ISBN 978-0-262-16147-3. <a href="978-0-262-16147-3" target="_blank">978-0-262-16147-3</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Olley, A. (2010). "Existence Precedes Essence - Meaning of the Stored-Program Concept" (PDF). History of Computing. Learning from the Past. IFIP WG 9.7 International Conference, HC 2010. IFIP Advances in Information and Communication Technology. Vol. 325. pp. 169–178. doi:10.1007/978-3-642-15199-6_17. ISBN 978-3-642-15198-9. <a href="978-3-642-15198-9" target="_blank">978-3-642-15198-9</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Graham, Loren R. (1993). Science in Russia and the Soviet Union: A Short History. Cambridge University Press. p. 256. ISBN 9780521287890. <a href="9780521287890" target="_blank">9780521287890</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> <li id="fn:21"><p>Edwin D. Reilly (2003). Milestones in computer science and information technology. Greenwood Publishing Group. p. 245. ISBN 978-1-57356-521-9. <a href="978-1-57356-521-9" target="_blank">978-1-57356-521-9</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></p></li> <li id="fn:22"><p>Emerson W. Pugh; Lyle R. Johnson; John H. Palmer (1991). IBM's 360 and Early 370 Systems. MIT Press. p. 15. ISBN 978-0-262-51720-1. <a href="978-0-262-51720-1" target="_blank">978-0-262-51720-1</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></p></li> <li id="fn:23"><p>Thomas Haigh; Mark Priestley; Crispen Rope (2016). ENIAC in Action:Making and Remaking the Modern Computer. MIT Press. pp. 153, 157, 164, 174, 194. ISBN 978-0-262-03398-5. <a href="978-0-262-03398-5" target="_blank">978-0-262-03398-5</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></p></li> <li id="fn:24"><p>Haigh, Thomas (2014). 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Fundamentals of Digital Switching Systems. Plenum Press. ISBN 0-306-41224-1. <a href="0-306-41224-1" target="_blank">0-306-41224-1</a> <a href="#fnref:32" class="footnote-back-ref">↩</a></p></li> <li id="fn:33"><p>Joel, A. E. (October 1958). "An Experimental Electronic Switching System" (PDF). Bell Laboratories Record. 36 (10): 359–363. Retrieved 13 October 2022. <a href="https://worldradiohistory.com/Archive-Bell-Laboratories-Record/50s/Bell-Laboratories-Record-1958-10.pdf#page=5" target="_blank">https://worldradiohistory.com/Archive-Bell-Laboratories-Record/50s/Bell-Laboratories-Record-1958-10.pdf#page=5</a> <a href="#fnref:33" class="footnote-back-ref">↩</a></p></li> <li id="fn:34"><p>"Electronic Central Office". Long Lines. Vol. 40, no. 5. December 1960. p. 16. <a href="https://www.telephonecollectors.info/index.php/browse/document-repository/catalogs-manuals/bell-system-we/pubs-docs/12290-60dec-longlines-att-r/file" target="_blank">https://www.telephonecollectors.info/index.php/browse/document-repository/catalogs-manuals/bell-system-we/pubs-docs/12290-60dec-longlines-att-r/file</a> <a href="#fnref:34" class="footnote-back-ref">↩</a></p></li> </ol>