Rational Software#RealTime

{{Short description|Defunct software company}}

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{{Update|part=article|date=July 2023}}{{Infobox company

| name = Rational Software

| logo = File:RationalSoftware.png

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| fate = Acquired by IBM

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| foundation = {{Start date|1981}}

| founder = Paul Levy and Mike Devlin

| defunct = {{End date|2003|02|20}}

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| key_people = Mike Devlin (previous CEO)

| industry = Application development tools

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| homepage = {{URL|https://www.ibm.com/software/uk/rational/}}

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}}{{About-distinguish|the software company that specializes in software architecture solutions|Rational Systems}}

Rational Machines is an enterprise founded by Paul Levy and Mike Devlin in 1981 to provide tools to expand the use of modern software engineering practices, particularly explicit modular architecture and iterative development. It changed its name in 1994 to Rational Software, and was sold for US$2.1 billion (equivalent to current US${{Format price|{{Inflation|US|2100000000|2003}}}}{{Inflation-fn|US}}) to IBM on February 21,{{cite web | url=https://www.lexpert.ca/big-deals/ibm-acquires-rational-software/343838 | title=IBM Acquires Rational Software }} 2003.