Editing SPICE (section)

== Origins ==
SPICE was developed at the Electronics Research Laboratory of the [[University of California, Berkeley]] by Laurence Nagel with direction from his research advisor, Prof. [[Donald Pederson]]. SPICE1 is largely a derivative of the CANCER program,<ref>{{cite journal |last1= Nagel |first1= L. W. |last2= Rohrer |first2= R. A. |title= Computer Analysis of Nonlinear Circuits, Excluding Radiation |journal= IEEE Journal of Solid-State Circuits |volume= 6 |date= August 1971 |issue= 4 |pages= 166–182 |doi= 10.1109/JSSC.1971.1050166 |bibcode= 1971IJSSC...6..166N}}</ref> which Nagel had worked on under Prof. Ronald Rohrer. CANCER is an acronym for "Computer Analysis of Nonlinear Circuits, Excluding Radiation".<ref>[http://www.designers-guide.org/Perspective/life-of-spice.pdf Life of SPICE] {{webarchive |url=https://web.archive.org/web/20120204190147/http://www.designers-guide.org/Perspective/life-of-spice.pdf |date=February 4, 2012 }}</ref> At these times many circuit simulators were developed under contracts with the [[United States Department of Defense]] that needed the ability to evaluate the [[radiation hardness]] of a circuit. When Nagel's original advisor, Prof. Rohrer, left Berkeley, Prof. Pederson became his advisor. Pederson insisted that CANCER, a proprietary program, be rewritten enough that restrictions could be removed and the program could be put in the [[public domain]].<ref>{{cite journal |last= Perry |first= T. |title= Donald O. Pederson |journal= IEEE Spectrum |date= June 1998 |pages= 22–27 |doi= 10.1109/6.681968 |volume= 35 |s2cid= 51633338 |url= <!-- http://www.designers-guide.org/dop1998.pdf -->}}</ref>

SPICE1 was first presented at a conference in 1973.<ref name=spice1/> SPICE1 is coded in [[FORTRAN]] and to construct the circuit equations uses [[nodal analysis]], which has limitations in representing inductors, floating voltage sources and the various forms of controlled sources.<ref name="vladimirescu94">{{cite book |last1=Vladimirescu |first1=Andrei |title=The SPICE Book |date=1994 |publisher=John Wiley & Sons, Inc. |location=New York}}</ref> SPICE1 has relatively few circuit elements available and uses a fixed-timestep [[transient analysis]]. The real popularity of SPICE started with SPICE2 in 1975.<ref name=spice2/> SPICE2, also coded in FORTRAN, is a much-improved program with more circuit elements, variable timestep transient analysis using either the trapezoidal (second order [[Adams-Moulton method]]) or the Gear integration method (also known as [[Backward differentiation formula|BDF]]), equation formulation via [[modified nodal analysis]] (avoiding the limitations of nodal analysis),<ref>{{cite journal |last1=Ruehli |first1=A. |last2=Brennan |first2=P. |title=The modified nodal approach to network analysis |journal=IEEE Transactions on Circuits and Systems |date=June 1975 |volume=22 |issue=6 |pages=504–509 |doi=10.1109/TCS.1975.1084079}}</ref> and an innovative FORTRAN-based memory allocation system.<ref>{{cite web |url=https://ltwiki.org/index.php?title=Recollections_of_the_%22The_Father_of_SPICE%22_Larry_Nagel |title=Recollections of the "The Father of SPICE" Larry Nagel |publisher=ltwiki.org |access-date=2024-02-21}}</ref> 
Ellis Cohen led development from version 2B to the industry standard SPICE 2G6, the last FORTRAN version, released in 1983.<ref>{{cite web |url=http://www.omega-enterprises.net/The%20Origins%20of%20SPICE.html |title=The Origins of SPICE |first1=Laurence W. |last1=Nagel |publisher=omega-enterprises.net |access-date=2024-02-21}}</ref><ref name=pederson84>Pederson, D.O. January 1984. "A Historical Review of Circuit Simulation." IEEE Transactions on Circuits and Systems, vol pp103-111.</ref> SPICE3 was developed by Thomas Quarles (with [[A. Richard Newton]] as advisor) in 1989. It is written in [[C (programming language)|C]], uses the same netlist syntax, and added [[X Window System]] plotting.<ref>Quarles, Thomas L., ''Analysis of Performance and Convergence Issues for Circuit Simulation'', Memorandum No. UCB/ERL M89/42, University of California, Berkeley, April 1989.</ref>

As an early [[public domain software]] program with [[source code]] available,<ref>[http://www.allaboutcircuits.com/textbook/reference/chpt-7/history-of-spice/ history-of-spice] {{webarchive |url=https://web.archive.org/web/20161009084508/http://www.allaboutcircuits.com/textbook/reference/chpt-7/history-of-spice/ |date=October 9, 2016 }} on allaboutcircuits.com. "The origin of SPICE traces back to another circuit simulation program called CANCER. Developed by professor Ronald Rohrer of U.C. Berkeley along with some of his students in the late 1960s, CANCER continued to be improved through the early 1970s. When Rohrer left Berkeley, CANCER was re-written and re-named to SPICE, released as version 1 to the public domain in May of 1972. Version 2 of SPICE was released in 1975 (version 2g6—the version used in this book—is a minor revision of this 1975 release). Instrumental in the decision to release SPICE as a public-domain computer program was professor Donald Pederson of Berkeley, who believed that all significant technical progress happens when information is freely shared. I for one thank him for his vision."</ref> SPICE was widely distributed and used. Its ubiquity became such that "to SPICE a circuit" remains synonymous with circuit simulation.<ref>{{cite web |last=Pescovitz |first=David |date=2002-05-01 |title=1972: The release of SPICE, still the industry standard tool for integrated circuit design |url=http://www.coe.berkeley.edu/labnotes/0502/history.html |url-status=dead |archive-url=https://web.archive.org/web/20150709211311/http://www.coe.berkeley.edu/labnotes/0502/history.html |archive-date=2015-07-09 |access-date=2007-03-10 |website=Lab Notes: Research from the Berkeley College of Engineering}}</ref> SPICE source code was from the beginning distributed by UC Berkeley for a nominal charge (to cover the cost of magnetic tape). The license originally included distribution restrictions for countries not considered friendly to the US, but the source code is currently covered by the [[BSD license]].

The birth of SPICE was named an [[List of IEEE milestones|IEEE Milestone]] in 2011; the entry mentions that SPICE "evolved to become the worldwide standard integrated circuit simulator".<ref>{{cite web |url=http://www.ieeeghn.org/wiki/index.php/Milestones:List_of_IEEE_Milestones |title=List of IEEE Milestones |work=IEEE Global History Network |publisher=IEEE |access-date=4 August 2011}}</ref> Nagel was awarded the 2019 IEEE Donald O. Pederson Award in Solid-State Circuits for the development of SPICE.<ref>[https://sscs.ieee.org/membership/awards/donald-o-pederson-solid-state-circuits-award/ Donald O. Pederson Solid-State Circuits Award], [[IEEE Solid-State Circuits Society]], June 2018</ref>