Editing IBM 704 (section)

{{Short description|Vacuum-tube computer system (1954)}}
[[File:IBM Electronic Data Processing Machine - GPN-2000-001881.jpg|thumb|280px|An IBM 704 computer at [[National Advisory Committee for Aeronautics|NACA]] in 1957]]
[[Image:IBM_704_mainframe.gif|right|thumb|280px|An IBM 704 computer, with [[IBM 727]] tape drives and [[IBM 780]] CRT display]]
[[File:Unità centrale - Museo scienza tecnologia Milano D1260 foto.jpg|thumb|280px|IBM 704 at the [[Museo Nazionale Scienza e Tecnologia Leonardo da Vinci]], Milan]]

The '''IBM 704''' is the model name of a large [[digital computer|digital]] [[mainframe computer]] introduced by [[IBM]] in 1954. Designed by [[John Backus]] and [[Gene Amdahl]], it was the first mass-produced computer with hardware for [[floating-point arithmetic]].<ref>{{Cite web |date=February 2001 |title=The IBM 704 |url=https://www.columbia.edu/cu/computinghistory/704.html |access-date=September 20, 2024 |website=columbia.edu |publisher=[[Columbia University]]}}</ref><ref name="IBM Archives">{{cite web 
  |url= http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP704.html
  |archive-url= https://web.archive.org/web/20050114203037/http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP704.html
  |url-status= dead
  |archive-date= January 14, 2005
  |title= 704 Data Processing System
  |author=<!--Staff writer(s); no by-line.--> 
  |date= 23 January 2003
  |website= IBM Archives – Exhibits – IBM Mainframes – Mainframes reference room – Mainframes product profiles
  |publisher= IBM 
  |access-date=2016-08-18
}}</ref> The IBM 704 ''Manual of operation'' states:<ref>{{cite web 
  |url= http://bitsavers.org/pdf/ibm/704/24-6661-2_704_Manual_1955.pdf
  |title= IBM Electronic Data-Processing Machines TYPE 704
  |author=<!--Staff writer(s); no by-line.--> 
  |date=1955 
  |website= IBM 704 Manual of Operation
  |publisher= International Business Machines Corporation
  |access-date=2017-12-28
}}</ref> 
<blockquote>
The type 704 Electronic Data-Processing Machine is a large-scale, high-speed electronic calculator controlled by an internally stored program of the single address type.
</blockquote>

The 704 at that time was thus regarded as "pretty much the only computer that could handle complex math".<ref>{{cite web 
  |url= https://www.theregister.co.uk/2015/02/26/my_aunt_was_a_human_assembler_at_nasa/
  |title= Assemblers were once people: My aunt did it for NASA
  |last1= Pesce
  |first1= Mark 
  |date= 26 Feb 2015
  |website= Software – Developer
  |publisher= The Register
  |access-date= 2016-08-18
}}</ref> The 704 was a significant improvement over the earlier [[IBM&nbsp;701]] in terms of architecture and implementation. Like the 701, the 704 used [[vacuum-tube]] logic circuitry, but increased the instruction size from [[18-bit computing|18 bits]] to [[36-bit computing|36 bits]], the same as the memory's word size. Changes from the 701 include the use of [[magnetic-core memory]] instead of [[Williams tube]]s, floating-point arithmetic instructions, 15-bit addressing and the addition of three [[index register]]s. To support these new features, the instructions were expanded to use the full 36-bit word. The new [[instruction set]], which is not compatible with the 701, became the base for the [[IBM 700/7000 series#Later scientific architecture (704/709/7090/7094)|"scientific architecture" subclass]] of the [[IBM 700/7000 series]] computers.

The 704 could execute up to 12,000 floating-point additions per second.<ref name="IBM Archives" /> IBM produced 123 type 704 systems between 1955 and 1960.<ref>{{cite web 
  |url= https://www.ibm.com/ibm/history/history/year_1954.html
  |title= History of IBM Timeline
  |author=<!--Staff writer(s); no by-line.--> 
  |date= 23 January 2003
  |publisher= IBM
  |access-date= 2019-07-04
}}</ref>