Editing System bus (section)

==Background scenario==
Many of the computers were based on the ''[[First Draft of a Report on the EDVAC]]'' report published in 1945. In what became known as the [[Von Neumann architecture]], a central control unit and [[arithmetic logic unit]] (ALU, which he called the central arithmetic part) were combined with [[computer memory]] and [[input/output|input and output]] functions to form a [[stored program computer]].<ref>{{cite web |title= First Draft of a Report on the EDVAC |author= John von Neumann |date= June 30, 1945 |url= http://qss.stanford.edu/~godfrey/vonNeumann/vnedvac.pdf |access-date= May 27, 2011 |url-status= dead |archive-url= https://web.archive.org/web/20130314123032/http://qss.stanford.edu/~godfrey/vonNeumann/vnedvac.pdf |archive-date= March 14, 2013 |author-link= John von Neumann }} Introduction and editing by Michael D. Godfrey, Stanford University, November 1992.</ref> The ''Report'' presented a general organization and  theoretical model of the computer, however, not the implementation of that model.<ref>{{cite journal |title= The Computer as von Neumann Planned It |author1= Michael D. Godfrey |author2= D. F. Hendry |year= 1993 |journal= IEEE Annals of the History of Computing |volume= 15 |number= 1 |pages= 11–21 |url= http://qss.stanford.edu/~godfrey/vonNeumann/edv-an.pdf |doi= 10.1109/85.194088 |s2cid= 569933 |url-status= dead |archive-url= https://web.archive.org/web/20110825104605/http://qss.stanford.edu/~godfrey/vonNeumann/edv-an.pdf |archive-date= 2011-08-25 }}</ref>
Soon designs integrated the control unit and ALU into what became known as the [[central processing unit]] (CPU).

Computers in the 1950s and 1960s were generally constructed in an ad-hoc fashion.
For example, the CPU, memory, and input/output units were each one or more cabinets connected by cables. Engineers used the common techniques of standardized bundles of wires and extended the concept as [[backplane]]s were used to hold [[printed circuit board]]s in these early machines. 
The name "bus" was already used for "[[busbar|bus bars]]" that carried electrical power to the various parts of electric machines, including early mechanical calculators.<ref>{{US Patent |3470421}} "Continuous Bus Bar for Connector Plate Back Panel Machine Wiring" Donald L. Shore et al., Filed August 30, 1967, issued September 30, 1969.</ref>
The advent of [[integrated circuit]]s vastly reduced the size of each computer unit, and buses became more standardized.<ref>{{US Patent |3462742}} "Computer System Adapted to be Constructed of Large Integrated Circuit Arrays" Henry S. Miller et al., Filed December 21, 1966, issued August 19, 1969.</ref>
Standard modules could be interconnected in more uniform ways and were easier to develop and maintain.